├── .gitignore
├── misc
    └── sfe.png
├── include
    ├── she.hpp
    └── she
    │   ├── defs.hpp
    │   ├── exceptions.hpp
    │   ├── serializations.hpp
    │   ├── random.hpp
    │   ├── plaintext.hpp
    │   ├── key.hpp
    │   └── ciphertext.hpp
├── tests
    ├── test_exceptions.cpp
    ├── serialization_formats.hpp
    ├── test_serializations.cpp
    ├── test_workflow.cpp
    ├── test_plaintext.cpp
    ├── test_random.cpp
    ├── test_key.cpp
    ├── test_ciphertext.cpp
    └── test_homomorphic_operations.cpp
├── .travis.yml
├── benchmarks
    ├── utils.hpp
    └── pir.cpp
├── src
    ├── plaintext.cpp
    ├── random.cpp
    ├── key.cpp
    └── ciphertext.cpp
├── Makefile
├── README.md
└── LICENSE


/.gitignore:
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1 | build
2 | 


--------------------------------------------------------------------------------
/misc/sfe.png:
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https://raw.githubusercontent.com/bogdan-kulynych/libshe/HEAD/misc/sfe.png


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/include/she.hpp:
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1 | #pragma once
2 | 
3 | #include "she/plaintext.hpp"
4 | #include "she/ciphertext.hpp"
5 | #include "she/key.hpp"


--------------------------------------------------------------------------------
/include/she/defs.hpp:
--------------------------------------------------------------------------------
 1 | #pragma once
 2 | 
 3 | #include <string>
 4 | 
 5 | 
 6 | namespace she
 7 | {
 8 | 
 9 | const unsigned int INTEGER_SERIALIZATION_BASE = 62;
10 | const std::string RANDOM_DEVICE = "/dev/urandom";
11 | 
12 | } // namespace she
13 | 


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/tests/test_exceptions.cpp:
--------------------------------------------------------------------------------
 1 | #define BOOST_TEST_DYN_LINK
 2 | #define BOOST_TEST_MODULE ExceptionsModule
 3 | #include <cstddef>
 4 | #include <boost/test/unit_test.hpp>
 5 | 
 6 | #include "she/exceptions.hpp"
 7 | 
 8 | using she::precondition_not_satisfied;
 9 | 
10 | 
11 | BOOST_AUTO_TEST_SUITE(ExceptionsSuite)
12 | 
13 | BOOST_AUTO_TEST_CASE(precondition_not_satisfied_construction_and_accessors)
14 | {
15 |     try {
16 |         ASSERT(true == false, "Obviously not.");
17 |     } catch (const precondition_not_satisfied & e) {
18 |         BOOST_CHECK_EQUAL(e.what(), "Obviously not. (true == false)");
19 |     }
20 | }
21 | 
22 | BOOST_AUTO_TEST_SUITE_END()
23 | 
24 | 


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/include/she/exceptions.hpp:
--------------------------------------------------------------------------------
 1 | #pragma once
 2 | 
 3 | #include <exception>
 4 | #include <string>
 5 | #include <sstream>
 6 | 
 7 | 
 8 | namespace she
 9 | {
10 | 
11 | class precondition_not_satisfied : public std::exception
12 | {
13 |  public:
14 |     precondition_not_satisfied(const std::string & msg) noexcept : _msg(msg) {};
15 |     const char * what() const noexcept { return _msg.c_str(); }
16 | 
17 |  private:
18 |     std::string _msg;
19 | };
20 | 
21 | } // namespace she
22 | 
23 | 
24 | #define ASSERT( condition, msg ) { \
25 |     if (!(condition)) { \
26 |         std::stringstream ss; \
27 |         ss << msg << " (" << #condition << ")"; \
28 |         throw she::precondition_not_satisfied(ss.str()); \
29 |     } }
30 | 


--------------------------------------------------------------------------------
/tests/serialization_formats.hpp:
--------------------------------------------------------------------------------
 1 | #include <boost/mpl/list.hpp>
 2 | 
 3 | #include <boost/archive/xml_oarchive.hpp>
 4 | #include <boost/archive/xml_iarchive.hpp>
 5 | #include <boost/archive/text_oarchive.hpp>
 6 | #include <boost/archive/text_iarchive.hpp>
 7 | 
 8 | using boost::archive::xml_oarchive;
 9 | using boost::archive::xml_iarchive;
10 | using boost::archive::text_oarchive;
11 | using boost::archive::text_iarchive;
12 | 
13 | 
14 | template <class InputArchive, class OutputArchive>
15 | struct Format {
16 |     using iarchive = InputArchive;
17 |     using oarchive = OutputArchive;
18 | };
19 | 
20 | using Formats = boost::mpl::list< Format<xml_iarchive, xml_oarchive>,
21 |                                   Format<text_iarchive, text_oarchive> >;
22 | 


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/tests/test_serializations.cpp:
--------------------------------------------------------------------------------
 1 | #define BOOST_TEST_DYN_LINK
 2 | #define BOOST_TEST_MODULE SerializationsModule
 3 | #include <cstddef>
 4 | #include <boost/test/unit_test.hpp>
 5 | 
 6 | #include <gmpxx.h>
 7 | 
 8 | #include "she/serializations.hpp"
 9 | #include "serialization_formats.hpp"
10 | 
11 | using std::stringstream;
12 | 
13 | 
14 | BOOST_AUTO_TEST_SUITE(SerializationsSuite)
15 | 
16 | BOOST_AUTO_TEST_CASE_TEMPLATE(mpz_class_serialization, Format, Formats)
17 | {
18 |     mpz_class z = mpz_class(1) << 10000;
19 |     mpz_class restored_z;
20 | 
21 |     stringstream ss;
22 |     {
23 |         typename Format::oarchive oa(ss);
24 |         oa << BOOST_SERIALIZATION_NVP(z);
25 |     }
26 |     {
27 |         typename Format::iarchive ia(ss);
28 |         ia >> BOOST_SERIALIZATION_NVP(restored_z);
29 |     }
30 | 
31 |     BOOST_CHECK(z == restored_z);
32 | }
33 | 
34 | BOOST_AUTO_TEST_SUITE_END()


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/include/she/serializations.hpp:
--------------------------------------------------------------------------------
 1 | #pragma once
 2 | 
 3 | #include <cstddef>
 4 | #include <string>
 5 | 
 6 | #include <boost/serialization/nvp.hpp>
 7 | #include <boost/serialization/split_free.hpp>
 8 | 
 9 | #include <gmpxx.h>
10 | 
11 | #include "defs.hpp"
12 | 
13 | 
14 | namespace boost { namespace serialization {
15 | 
16 | template<class Archive>
17 | void save(Archive & ar, const mpz_class & value, const unsigned int version)
18 | {
19 |     std::string repr = value.get_str(she::INTEGER_SERIALIZATION_BASE);
20 |     ar & BOOST_SERIALIZATION_NVP(repr);
21 | }
22 | 
23 | template<class Archive>
24 | void load(Archive & ar, mpz_class & value, const unsigned int version)
25 | {
26 |     std::string repr;
27 |     ar & BOOST_SERIALIZATION_NVP(repr);
28 |     value.set_str(repr, she::INTEGER_SERIALIZATION_BASE);
29 | }
30 | 
31 | }} // namespace boost::serialization
32 | 
33 | BOOST_SERIALIZATION_SPLIT_FREE(mpz_class)
34 | 


--------------------------------------------------------------------------------
/include/she/random.hpp:
--------------------------------------------------------------------------------
 1 | #pragma once
 2 | 
 3 | #include <cstddef>
 4 | #include <vector>
 5 | #include <utility>
 6 | #include <map>
 7 | 
 8 | #include <gmpxx.h>
 9 | 
10 | 
11 | namespace she
12 | {
13 | 
14 | class CSPRNG
15 | {
16 |  public:
17 |     CSPRNG() noexcept;
18 | 
19 |     mpz_class get_bits(unsigned int bits) const noexcept;
20 |     mpz_class get_range_bits(unsigned int bits) const noexcept;
21 |     mpz_class get_range(const mpz_class & upper_bound) const noexcept;
22 | 
23 |  private:
24 |     mutable gmp_randclass _generator;
25 | };
26 | 
27 | 
28 | class PseudoRandomStream
29 | {
30 |  public:
31 |     PseudoRandomStream(unsigned int size, unsigned int seed);
32 | 
33 |     const mpz_class & next() const noexcept;
34 |     const void reset() const noexcept;
35 |     static void reset_cache() noexcept { cached_values.clear(); }
36 | 
37 |  private:
38 |     unsigned int _size;
39 |     unsigned int _seed;
40 |     mutable gmp_randclass _generator;
41 | 
42 |     mutable size_t _current_value;
43 | 
44 |     using keys_t = std::pair<unsigned int, unsigned int>;
45 |     using values_t = std::vector<mpz_class>;
46 | 
47 |     static std::map<keys_t, values_t> cached_values;
48 | };
49 | 
50 | } // namespace she
51 | 


--------------------------------------------------------------------------------
/.travis.yml:
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 1 | language: cpp
 2 | 
 3 | compiler:
 4 | - g++
 5 | 
 6 | env:
 7 |   global:
 8 |     secure: UCL6P2+jglTd/qzlnx2gZ/mlS5W7AAtC8W5vePE+SmXVuVJLDEA96PJmKCi2t5MuYUhimJFZ4UsbTkQ7yZU7SjHeDN1YhOcK1dih0hPU9ml+Wcuplj4P3jL0UBFQmXbglup2VO3xjoxdEHCTlhQTm5WGg0M1n+Lx/P+n8vvixCk=
 9 | 
10 | before_install:
11 | - sudo add-apt-repository -y ppa:boost-latest/ppa
12 | - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
13 | - sudo apt-get update -qq
14 | 
15 | install:
16 | # GCC 4.9
17 | - sudo apt-get install -qq g++-4.9 libstdc++-4.9-dev
18 | - export CC="gcc-4.9"
19 | - export CXX="g++-4.9"
20 | - export GCOV="gcov-4.9"
21 | 
22 | # lcov 1.11
23 | - wget http://ftp.de.debian.org/debian/pool/main/l/lcov/lcov_1.11.orig.tar.gz
24 | - tar xf lcov_1.11.orig.tar.gz
25 | - sudo make -C lcov-1.11/ install
26 | 
27 | # Boost, GMP
28 | - sudo apt-get install -qq boost1.55 libgmp-dev
29 | 
30 | # Coveralls
31 | - gem install coveralls-lcov
32 | 
33 | script:
34 | - make tests
35 | - make
36 | 
37 | after_success:
38 | - ${GCOV} --version
39 | - lcov --version
40 | - make coverage GCOV=${GCOV}
41 | - coveralls-lcov --repo-token ${COVERALLSTOKEN} build/coverage.info
42 | 
43 | cache:
44 | - apt
45 | 
46 | notifications:
47 |   email:
48 |     on_failure: change
49 | 
50 |   webhooks:
51 |     urls:
52 |       - https://webhooks.gitter.im/e/08d9936d9d017472517e
53 |     on_success: change
54 |     on_failure: always
55 |     on_start: false
56 | 


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/benchmarks/utils.hpp:
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 1 | #include <ctime>
 2 | #include <map>
 3 | #include <string>
 4 | #include <chrono>
 5 | #include <iostream>
 6 | 
 7 | 
 8 | using chrono_t = std::chrono::duration<double>;
 9 | std::map<std::string, chrono_t> _timer_global;
10 | 
11 | 
12 | #define START_TIMER( section, group ) \
13 |         _timer_global.emplace(std::pair<std::string, chrono_t>(group, {})); \
14 |         std::string _timer_group = group; \
15 |         std::cout << "> " << section << std::endl; \
16 |         std::chrono::time_point<std::chrono::system_clock> _timer_start, _timer_end; \
17 |         _timer_start = std::chrono::system_clock::now();
18 | 
19 | #define END_TIMER() \
20 |         _timer_end = std::chrono::system_clock::now(); \
21 |         chrono_t elapsed_seconds = _timer_end - _timer_start; \
22 |         _timer_global[_timer_group] += elapsed_seconds; \
23 |         std::cout << "< Seconds: " << elapsed_seconds.count() << std::endl; \
24 |         std::cout << std::endl;
25 | 
26 | #define TIMER_STATS() \
27 |         chrono_t _total_seconds {}; \
28 |         for (const auto & entry : _timer_global) { \
29 |             const auto & group = entry.first; \
30 |             const auto & elapsed_seconds = entry.second; \
31 |             std::cout << "Group " << group << ". "; \
32 |             std::cout << "Seconds: " << elapsed_seconds.count() << std::endl; \
33 |             _total_seconds += elapsed_seconds; \
34 |         } \
35 |         std::cout << "-----" << std::endl; \
36 |         std::cout << "Total seconds: " << _total_seconds.count() << std::endl; \
37 |         std::cout << std::endl;


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/src/plaintext.cpp:
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 1 | #include <cmath>
 2 | 
 3 | #include "she.hpp"
 4 | #include "she/exceptions.hpp"
 5 | 
 6 | using std::min;
 7 | using std::max;
 8 | using std::vector;
 9 | 
10 | 
11 | namespace she
12 | {
13 | 
14 | PlaintextArray & PlaintextArray::operator^=(const PlaintextArray & other) noexcept
15 | {
16 |     const size_t n = min(_elements.size(), other._elements.size());
17 | 
18 |     // Do bit-wise XOR
19 |     for (size_t i = 0; i < n; ++i) {
20 |         _elements[i] = _elements[i] ^ other._elements[i];
21 |     }
22 | 
23 |     // If sizes don't match pad with zeros from the right
24 |     for (size_t i = n; i < other._elements.size(); ++i) {
25 |         _elements.push_back(other._elements[i]);
26 |     }
27 | 
28 |     return *this;
29 | }
30 | 
31 | PlaintextArray & PlaintextArray::operator&=(const PlaintextArray & other) noexcept
32 | {
33 |     const size_t n = min(_elements.size(), other._elements.size());
34 | 
35 |     // Do bit-wise AND
36 |     for (size_t i = 0; i < n; ++i) {
37 |         _elements[i] = _elements[i] & other._elements[i];
38 |     }
39 | 
40 |     // If sizes don't match pad with ones from the right
41 |     for (size_t i = n; i < other._elements.size(); ++i) {
42 |         _elements.push_back(other._elements[i]);
43 |     }
44 | 
45 |     return *this;
46 | }
47 | 
48 | PlaintextArray & PlaintextArray::extend(const PlaintextArray & other) noexcept
49 | {
50 |     for (const auto & element : other._elements) {
51 |         _elements.push_back(element);
52 |     }
53 | 
54 |     return *this;
55 | }
56 | 
57 | bool PlaintextArray::operator==(const PlaintextArray & other) const noexcept
58 | {
59 |     return _elements == other._elements;
60 | }
61 | 
62 | } // namespace she


--------------------------------------------------------------------------------
/src/random.cpp:
--------------------------------------------------------------------------------
 1 | #include <random>
 2 | 
 3 | #include "she/random.hpp"
 4 | #include "she/defs.hpp"
 5 | 
 6 | using std::out_of_range;
 7 | using std::random_device;
 8 | using std::make_pair;
 9 | using std::map;
10 | using std::pair;
11 | using std::vector;
12 | 
13 | 
14 | namespace she
15 | {
16 | 
17 | CSPRNG::CSPRNG() noexcept : _generator(gmp_randinit_default)
18 | {
19 |     // Generate 64-bit seed
20 |     random_device dev(RANDOM_DEVICE);
21 |     mpz_class seed32 = dev();
22 |     _generator.seed(seed32 << 32 | dev());
23 | }
24 | 
25 | mpz_class
26 | CSPRNG::get_bits(unsigned int bits) const noexcept
27 | {
28 |     return _generator.get_z_bits(bits);
29 | }
30 | 
31 | mpz_class
32 | CSPRNG::get_range_bits(unsigned int bits) const noexcept
33 | {
34 |     return _generator.get_z_range(mpz_class(1) << bits);;
35 | }
36 | 
37 | mpz_class
38 | CSPRNG::get_range(const mpz_class & upper_bound) const noexcept
39 | {
40 |     return _generator.get_z_range(upper_bound);
41 | }
42 | 
43 | 
44 | PseudoRandomStream::PseudoRandomStream(unsigned int size, unsigned int seed) :
45 |   _size(size),
46 |   _seed(seed),
47 |   _generator(gmp_randinit_default),
48 |   _current_value(0)
49 | {
50 |     _generator.seed(seed);
51 | }
52 | 
53 | map<PseudoRandomStream::keys_t, PseudoRandomStream::values_t> PseudoRandomStream::cached_values = {};
54 | 
55 | const mpz_class & PseudoRandomStream::next() const noexcept
56 | {
57 |     keys_t context{_size, _seed};
58 |     auto it = PseudoRandomStream::cached_values.find(context);
59 | 
60 |     if (it != cached_values.end()) {
61 |         if (it->second.size() <= _current_value) {
62 |             it->second.push_back(_generator.get_z_bits(_size));
63 |         }
64 |     } else {
65 |         cached_values[context] = vector<mpz_class>{_generator.get_z_bits(_size)};
66 |     }
67 | 
68 |     return cached_values[context][_current_value++];
69 | }
70 | 
71 | const void PseudoRandomStream::reset() const noexcept
72 | {
73 |     _current_value = 0;
74 | }
75 | 
76 | }
77 | 


--------------------------------------------------------------------------------
/tests/test_workflow.cpp:
--------------------------------------------------------------------------------
 1 | #define BOOST_TEST_DYN_LINK
 2 | #define BOOST_TEST_MODULE WorkflowModule
 3 | #include <cstddef>
 4 | #include <boost/test/unit_test.hpp>
 5 | 
 6 | #include <boost/archive/text_oarchive.hpp>
 7 | #include <boost/archive/text_iarchive.hpp>
 8 | 
 9 | #include <sstream>
10 | #include <vector>
11 | 
12 | #include "she.hpp"
13 | 
14 | using std::vector;
15 | using std::stringstream;
16 | 
17 | using boost::archive::text_oarchive;
18 | using boost::archive::text_iarchive;
19 | 
20 | using she::ParameterSet;
21 | using she::PrivateKey;
22 | using she::CompressedCiphertext;
23 | using she::EncryptedArray;
24 | using she::PlaintextArray;
25 | 
26 | 
27 | BOOST_AUTO_TEST_SUITE(WorkflowSuite)
28 | 
29 | BOOST_AUTO_TEST_CASE(sfe_simulation)
30 | {
31 |     stringstream ss1;
32 |     stringstream ss2;
33 | 
34 |     PrivateKey * sk;
35 | 
36 |     // ----------- CLIENT ----------------------------------------------
37 |     {
38 |         const auto params = ParameterSet::generate_parameter_set(22, 1, 42);
39 | 
40 |         // Generate private key
41 |         sk = new PrivateKey(params);
42 | 
43 |         // Encrypt plaintext
44 |         const vector<bool> plaintext = {1, 0, 1, 0};
45 |         const auto compressed_ciphertext = sk->encrypt(plaintext);
46 | 
47 |         text_oarchive oa1(ss1);
48 |         oa1 << compressed_ciphertext;
49 |     }
50 | 
51 |     // ----------- SERVER ----------------------------------------------
52 | 
53 |     {
54 |         CompressedCiphertext received_compressed_ciphertext;
55 |         text_iarchive ia1(ss1);
56 |         ia1 >> received_compressed_ciphertext;
57 | 
58 |         // Expand the ciphertext to perform operations
59 |         const auto ciphertext = received_compressed_ciphertext.expand();
60 | 
61 |         // Execute some algorithm
62 |         const vector<bool> another_plaintext = {1, 1, 1, 1};
63 |         const auto response = ciphertext ^ PlaintextArray(another_plaintext);
64 | 
65 |         // Serialize result
66 |         text_oarchive oa2(ss2);
67 |         oa2 << response;
68 |     }
69 | 
70 |     // ----------- CLIENT ----------------------------------------------
71 | 
72 |     {
73 |         EncryptedArray received_response;
74 |         text_iarchive ia2(ss2);
75 |         ia2 >> received_response;
76 | 
77 |         const auto decrypted_response = sk->decrypt(received_response);
78 |         const vector<bool> expected_result = {0, 1, 0, 1};
79 | 
80 |         BOOST_CHECK(decrypted_response == expected_result);
81 |     }
82 | }
83 | 
84 | BOOST_AUTO_TEST_SUITE_END()
85 | 


--------------------------------------------------------------------------------
/include/she/plaintext.hpp:
--------------------------------------------------------------------------------
 1 | #pragma once
 2 | 
 3 | #include <cstddef>
 4 | #include <memory>
 5 | 
 6 | #include <boost/operators.hpp>
 7 | #include <boost/serialization/nvp.hpp>
 8 | #include <boost/serialization/access.hpp>
 9 | #include <boost/serialization/vector.hpp>
10 | #include <boost/serialization/split_free.hpp>
11 | 
12 | #include "serializations.hpp"
13 | 
14 | 
15 | namespace she
16 | {
17 | 
18 | class EncryptedArray;
19 | 
20 | class PlaintextArray : boost::equality_comparable<PlaintextArray
21 |                      , boost::xorable<PlaintextArray
22 |                      , boost::andable<PlaintextArray
23 |                      > > >
24 | {
25 |  friend class EncryptedArray;
26 |  public:
27 |     // Construct from plaintext
28 |     PlaintextArray(const std::vector<bool> & plaintext) noexcept : _elements(plaintext) {}
29 | 
30 |     // Empty ctor for deserialization purposes
31 |     PlaintextArray() noexcept {};
32 | 
33 |     // Convert to bits
34 |     operator const std::vector<bool>() const { return _elements; };
35 |     operator std::vector<bool>() { return _elements; };
36 | 
37 |     // Element-wise addition (XOR)
38 |     PlaintextArray & operator^=(const PlaintextArray &) noexcept;
39 | 
40 |     // Element-wise multiplication (AND)
41 |     PlaintextArray & operator&=(const PlaintextArray &) noexcept;
42 | 
43 |     // Homomorphic equality comparison
44 |     const PlaintextArray equal(const std::vector<PlaintextArray> &) const noexcept;
45 |     const EncryptedArray equal(const std::vector<EncryptedArray> &) const noexcept;
46 | 
47 |     // Homomorphic select function
48 |     const PlaintextArray select(const std::vector<PlaintextArray> &) const noexcept;
49 |     const EncryptedArray select(const std::vector<EncryptedArray> &) const noexcept;
50 | 
51 |     // Extend array
52 |     PlaintextArray & extend(const PlaintextArray & other) noexcept;
53 | 
54 |     // EncryptedArray compatibility
55 |     unsigned int degree() const noexcept { return 0; }
56 |     unsigned int max_degree() const noexcept { return 0; }
57 | 
58 |     // Ciphertext size
59 |     size_t size() const noexcept { return _elements.size(); }
60 | 
61 |     // Encrypted bits
62 |     const std::vector<bool>& elements() const noexcept { return _elements; }
63 |     std::vector<bool>& elements() noexcept { return _elements; }
64 | 
65 |     // Representation comparison
66 |     bool operator==(const PlaintextArray &) const noexcept;
67 | 
68 |  private:
69 |     friend class boost::serialization::access;
70 | 
71 |     std::vector<bool> _elements;
72 | 
73 |     template<class Archive>
74 |     void serialize(Archive & ar, unsigned int const version) const
75 |     {
76 |         ar & BOOST_SERIALIZATION_NVP(_elements);
77 |     }
78 | };
79 | 
80 | } // namespace she


--------------------------------------------------------------------------------
/tests/test_plaintext.cpp:
--------------------------------------------------------------------------------
  1 | #define BOOST_TEST_DYN_LINK
  2 | #define BOOST_TEST_MODULE PlaintextModule
  3 | #include <cstddef>
  4 | #include <boost/test/unit_test.hpp>
  5 | 
  6 | #include "she.hpp"
  7 | #include "serialization_formats.hpp"
  8 | 
  9 | using std::stringstream;
 10 | using std::vector;
 11 | 
 12 | using she::PlaintextArray;
 13 | 
 14 | 
 15 | BOOST_AUTO_TEST_SUITE(PlaintextArraySuite)
 16 | 
 17 | BOOST_AUTO_TEST_CASE(plaintext_array_construction_accessors_and_comparison)
 18 | {
 19 |     const vector<bool> raw_plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 20 | 
 21 |     const PlaintextArray a1(raw_plaintext);
 22 | 
 23 |     BOOST_CHECK_EQUAL(a1.degree(), 0);
 24 |     BOOST_CHECK_EQUAL(a1.size(), raw_plaintext.size());
 25 | 
 26 |     const PlaintextArray a2(raw_plaintext);
 27 | 
 28 |     BOOST_CHECK_EQUAL(a2.degree(), 0);
 29 | 
 30 |     BOOST_CHECK(a1 == a2);
 31 |     BOOST_CHECK(!(a1 != a2));
 32 | }
 33 | 
 34 | BOOST_AUTO_TEST_CASE(plaintext_array_implicit_conversions)
 35 | {
 36 |     vector<bool> raw_plaintext = { 1, 0, 1, 0 };
 37 | 
 38 |     const PlaintextArray array = raw_plaintext;
 39 |     BOOST_CHECK(array == raw_plaintext);
 40 | }
 41 | 
 42 | // FIXME: The commented code doesn't compile, but it should
 43 | BOOST_AUTO_TEST_CASE_TEMPLATE(plaintext_array_serialization, Format, Formats)
 44 | {
 45 |     const vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 46 |     const PlaintextArray array(plaintext);
 47 | 
 48 |     PlaintextArray restored_array;
 49 | 
 50 |     // stringstream ss;
 51 |     // {
 52 |     //     typename Format::oarchive oa(ss);
 53 |     //     oa << BOOST_SERIALIZATION_NVP(array);
 54 |     // }
 55 |     // {
 56 |     //     typename Format::iarchive ia(ss);
 57 |     //     ia >> BOOST_SERIALIZATION_NVP(restored_array);
 58 |     // }
 59 | 
 60 |     // BOOST_CHECK(array == restored_array);
 61 | }
 62 | 
 63 | BOOST_AUTO_TEST_CASE(plaintext_arrays_extend_empty)
 64 | {
 65 |     PlaintextArray array;
 66 |     const auto plaintext = PlaintextArray({1, 1, 1, 1});
 67 |     array.extend(plaintext);
 68 | 
 69 |     BOOST_CHECK(array.elements() == plaintext.elements());
 70 | }
 71 | 
 72 | BOOST_AUTO_TEST_CASE(plaintext_arrays_extend)
 73 | {
 74 |     const auto expected_result = PlaintextArray({1, 1, 0, 0, 0, 0, 1, 1});
 75 | 
 76 |     PlaintextArray array({1, 1, 0, 0});
 77 |     const auto plaintext = PlaintextArray({0, 0, 1, 1});
 78 |     array.extend(plaintext);
 79 | 
 80 |     BOOST_CHECK(array.elements() == expected_result.elements());
 81 | }
 82 | 
 83 | BOOST_AUTO_TEST_CASE(plaintext_arrays_concat)
 84 | {
 85 |     const vector< vector<bool>> raw_plaintext_inputs = {
 86 |         {0, 1, 0, 1},
 87 |         {1, 0, 1, 0},
 88 |         {0, 0, 0, 0},
 89 |         {1, 1, 1, 1}
 90 |     };
 91 | 
 92 |     vector<PlaintextArray> plaintext_inputs;
 93 |     for (const auto & raw_plaintext_input : raw_plaintext_inputs) {
 94 |         plaintext_inputs.push_back(PlaintextArray(raw_plaintext_input));
 95 |     }
 96 | 
 97 |     const auto expected_result = PlaintextArray({0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1});
 98 | 
 99 |     BOOST_CHECK(concat(plaintext_inputs) == expected_result);
100 | }
101 | 
102 | BOOST_AUTO_TEST_SUITE_END()


--------------------------------------------------------------------------------
/tests/test_random.cpp:
--------------------------------------------------------------------------------
  1 | #define BOOST_TEST_DYN_LINK
  2 | #define BOOST_TEST_MODULE RandomModule
  3 | #include <cstddef>
  4 | #include <boost/test/unit_test.hpp>
  5 | 
  6 | #include <gmpxx.h>
  7 | 
  8 | #include "she/random.hpp"
  9 | 
 10 | using std::vector;
 11 | using std::abs;
 12 | 
 13 | using she::CSPRNG;
 14 | using she::PseudoRandomStream;
 15 | 
 16 | 
 17 | BOOST_AUTO_TEST_SUITE(CSPRNG_Suite)
 18 | 
 19 | BOOST_AUTO_TEST_CASE(generator_construction)
 20 | {
 21 |     const CSPRNG generator;
 22 | }
 23 | 
 24 | BOOST_AUTO_TEST_CASE(generator_get_bits)
 25 | {
 26 |     const CSPRNG generator;
 27 | 
 28 |     const size_t iterations = 15;
 29 |     const int bits = 100;
 30 | 
 31 |     for (size_t i = 0; i < iterations; ++i) {
 32 |         const auto output = generator.get_bits(bits);
 33 |         const auto output_bits = static_cast<int>(mpz_sizeinbase(output.get_mpz_t(), 2));
 34 |         // BOOST_CHECK_EQUAL(output_bits, bits);
 35 |     }
 36 | }
 37 | 
 38 | BOOST_AUTO_TEST_CASE(generator_get_range_bits)
 39 | {
 40 |     const CSPRNG generator;
 41 | 
 42 |     const size_t iterations = 30;
 43 |     const int bits = 100;
 44 | 
 45 |     for (size_t i = 0; i < iterations; ++i) {
 46 |         const auto output = generator.get_range_bits(bits);
 47 |         const auto output_bits = static_cast<int>(mpz_sizeinbase(output.get_mpz_t(), 2));
 48 |         BOOST_CHECK_LT(output_bits, bits + 1);
 49 |     }
 50 | }
 51 | 
 52 | BOOST_AUTO_TEST_CASE(generator_get_range)
 53 | {
 54 |     const CSPRNG generator;
 55 | 
 56 |     const size_t iterations = 15;
 57 |     const int bits = 100;
 58 |     mpz_class upper_bound = mpz_class(1) << bits;
 59 | 
 60 |     for (size_t i = 0; i < iterations; ++i) {
 61 |         mpz_class output = generator.get_range(upper_bound);
 62 |         BOOST_CHECK(output <= upper_bound);
 63 |     }
 64 | }
 65 | 
 66 | BOOST_AUTO_TEST_SUITE_END()
 67 | 
 68 | 
 69 | BOOST_AUTO_TEST_SUITE(PseudoRandomStreamSuite)
 70 | 
 71 | BOOST_AUTO_TEST_CASE(prf_stream_construction)
 72 | {
 73 |     const PseudoRandomStream prf_stream(100, 42);
 74 | }
 75 | 
 76 | BOOST_AUTO_TEST_CASE(prf_stream_output_generation)
 77 | {
 78 |     const int bits = 100;
 79 |     const unsigned int seed = 42;
 80 |     const PseudoRandomStream prf_stream(bits, seed);
 81 |     const auto prf_stream_outputs = { prf_stream.next(), prf_stream.next(), prf_stream.next() };
 82 | 
 83 |     for (const auto & prf_stream_output : prf_stream_outputs)
 84 |     {
 85 |         const auto output_bits = static_cast<int>(mpz_sizeinbase(prf_stream_output.get_mpz_t(), 2));
 86 |         // BOOST_CHECK_EQUAL(output_bits, bits);
 87 |     }
 88 | }
 89 | 
 90 | BOOST_AUTO_TEST_CASE(prf_stream_determinism)
 91 | {
 92 |     const int bits = 100;
 93 |     const unsigned int seed = 42;
 94 |     const PseudoRandomStream nostradamus(bits, seed), pythia(bits, seed), paul_the_octopus(bits, seed + 1);
 95 | 
 96 |     const size_t iterations = 5;
 97 | 
 98 |     for (size_t i = 0; i < iterations; ++i) {
 99 |         const auto pythia_output = pythia.next();
100 |         BOOST_CHECK(nostradamus.next() == pythia_output);
101 |         BOOST_CHECK(pythia_output != paul_the_octopus.next());
102 |     }
103 | }
104 | 
105 | BOOST_AUTO_TEST_CASE(prf_stream_cache_reset)
106 | {
107 |     const PseudoRandomStream nostradamus(10, 10), pythia(10, 10);
108 | 
109 |     const mpz_class & nostradamus_output_reference = nostradamus.next();
110 |     const mpz_class nostradamus_output_copy = mpz_class(nostradamus_output_reference);
111 | 
112 |     const mpz_class pythia_output = mpz_class(pythia.next());
113 | 
114 |     BOOST_CHECK(nostradamus_output_reference == pythia_output);
115 |     BOOST_CHECK(nostradamus_output_copy == pythia_output);
116 | 
117 |     PseudoRandomStream::reset_cache();
118 | 
119 |     BOOST_CHECK(nostradamus_output_reference != pythia_output);
120 |     BOOST_CHECK(nostradamus_output_copy == pythia_output);
121 | }
122 | 
123 | BOOST_AUTO_TEST_SUITE_END()
124 | 


--------------------------------------------------------------------------------
/Makefile:
--------------------------------------------------------------------------------
  1 | SHELL              := /bin/bash
  2 | 
  3 | BOOSTDIR           := /usr/local/lib
  4 | PREFIX             := /usr/local
  5 | 
  6 | CXXFLAGS           := -Wall -fPIC -std=c++11 -pedantic
  7 | 
  8 | INCDIR             := include
  9 | SRCDIR             := src
 10 | BUILDDIR           := build
 11 | TESTDIR            := tests
 12 | BENCHDIR           := benchmarks
 13 | 
 14 | LIBS               := -L$(BOOSTDIR) -lboost_serialization -lstdc++ -lgmp
 15 | TESTLIBS           := -L$(BOOSTDIR) -lboost_unit_test_framework
 16 | INC                := -I$(INCDIR)
 17 | 
 18 | LIBSOURCES         := $(wildcard $(SRCDIR)/*.cpp)
 19 | TESTSOURCES        := $(wildcard $(TESTDIR)/*.cpp)
 20 | BENCHSOURCES       := $(wildcard $(BENCHDIR)/*.cpp)
 21 | LIBOBJECTS         := $(patsubst %.cpp,$(BUILDDIR)/%.o, $(LIBSOURCES))
 22 | TESTOBJECTS        := $(patsubst %.cpp,$(BUILDDIR)/%.o, $(TESTSOURCES))
 23 | BENCHOBJECTS       := $(patsubst %.cpp,$(BUILDDIR)/%.o, $(BENCHSOURCES))
 24 | TESTTARGETS        := $(patsubst %.cpp,$(BUILDDIR)/%, $(TESTSOURCES))
 25 | BENCHTARGETS       := $(patsubst %.cpp,$(BUILDDIR)/%, $(BENCHSOURCES))
 26 | 
 27 | LIBTARGET          := $(BUILDDIR)/libshe.so
 28 | 
 29 | TESTOPTS           := --log_level=test_suite
 30 | COVERAGEFILE       := $(BUILDDIR)/coverage.info
 31 | GCOV               := gcov
 32 | 
 33 | 
 34 | define \n
 35 | 
 36 | 
 37 | endef
 38 | 
 39 | # Messages
 40 | 
 41 | LINK     := > Link
 42 | COMPILE  := > Cmpl
 43 | EXEC     := > Exec
 44 | 
 45 | .PHONY: all
 46 | all: library
 47 | 
 48 | # Library
 49 | 
 50 | .PHONY: library
 51 | library: CXXFLAGS += -O3
 52 | library: $(LIBTARGET)
 53 | 
 54 | $(LIBTARGET): $(LIBOBJECTS)
 55 | 	@echo "$(LINK): $^"
 56 | 	@$(CXX) $(LDFLAGS) -shared $^ $(LIBS) -o $@
 57 | 
 58 | $(LIBOBJECTS): $(BUILDDIR)/%.o: %.cpp
 59 | 	@echo "$(COMPILE): $^"
 60 | 	@mkdir -p $(BUILDDIR)/$(SRCDIR)
 61 | 	@$(CXX) $(CXXFLAGS) $(INC) -c $^ -o $@
 62 | 
 63 | # Tests
 64 | 
 65 | .PHONY: tests
 66 | tests: CXXFLAGS += -O0 -DDEBUG -g --coverage
 67 | tests: LDFLAGS = --coverage
 68 | tests: $(LIBSOURCES)
 69 | tests: $(TESTSOURCES)
 70 | tests: $(TESTTARGETS)
 71 | 
 72 | $(TESTTARGETS): $(LIBOBJECTS)
 73 | $(TESTTARGETS): $(BUILDDIR)/%: $(BUILDDIR)/%.o
 74 | 	@echo "$(LINK): $^"
 75 | 	@$(CXX) $(LDFLAGS) $^ $(TESTLIBS) $(LIBS) -o $@
 76 | 	$(foreach exe,$@,@echo "$(EXEC): $(exe)" && ./$(exe) $(TESTOPTS)${\n})
 77 | 
 78 | $(TESTOBJECTS): $(BUILDDIR)/%.o: %.cpp
 79 | 	@echo "$(COMPILE): $^"
 80 | 	@mkdir -p $(BUILDDIR)/$(TESTDIR)
 81 | 	@$(CXX) $(CXXFLAGS) $(INC) -c $^ -o $@
 82 | 
 83 | # Coverage report
 84 | 
 85 | .PHONY: coverage
 86 | coverage:
 87 | 	@lcov --gcov-tool $(GCOV) --directory . --capture --output-file $(COVERAGEFILE)
 88 | 	@lcov --gcov-tool $(GCOV) --remove $(COVERAGEFILE) 'tests/*' '/usr/*' --output-file $(COVERAGEFILE) 2> /dev/null
 89 | 	@lcov --gcov-tool $(GCOV) --list $(COVERAGEFILE)
 90 | 	@genhtml $(COVERAGEFILE) --output-directory $(BUILDDIR)/coverage
 91 | 
 92 | # Benchmarks
 93 | 
 94 | .PHONY: benchmarks
 95 | benchmarks: $(LIBSOURCES)
 96 | benchmarks: $(BENCHSOURCES)
 97 | benchmarks: $(BENCHTARGETS)
 98 | 	$(foreach exe,$<,@echo "$(EXEC): $(exe)" && ./$(exe) $(TESTOPTS)${\n})
 99 | 
100 | $(BENCHTARGETS): $(LIBOBJECTS)
101 | $(BENCHTARGETS): $(BUILDDIR)/%: $(BUILDDIR)/%.o
102 | 	@echo "$(LINK): $^"
103 | 	@$(CXX) $(LDFLAGS) $^ $(LIBS) -o $@
104 | 
105 | $(BENCHOBJECTS): $(BUILDDIR)/%.o: %.cpp
106 | 	@echo "$(COMPILE): $^"
107 | 	@mkdir -p $(BUILDDIR)/$(BENCHDIR)
108 | 	@$(CXX) $(CXXFLAGS) $(INC) -c $^ -o $@
109 | 
110 | # Installation
111 | 
112 | .PHONY: install
113 | install: $(BUILDDIR)/$(LIBTARGET)
114 | 	@mkdir -p $(PREFIX)/include
115 | 	@mkdir -p $(PREFIX)/lib
116 | 	cp -rf $(INCDIR) -t $(PREFIX)
117 | 	cp -f $(BUILDDIR)/$(LIBTARGET) -t $(PREFIX)/lib/
118 | 	ldconfig
119 | 
120 | .PHONY: uninstall
121 | uninstall:
122 | 	rm $(PREFIX)/lib/$(LIBTARGET)
123 | 	$(foreach header,$(shell ls -1 $(INCDIR)),rm -r $(PREFIX)/include/$(header)${\n})
124 | 	ldconfig
125 | 
126 | .PHONY: clean
127 | clean:
128 | 	rm -rf $(BUILDDIR)
129 | 


--------------------------------------------------------------------------------
/include/she/key.hpp:
--------------------------------------------------------------------------------
  1 | #pragma once
  2 | 
  3 | #include <cstddef>
  4 | #include <vector>
  5 | #include <memory>
  6 | 
  7 | #include <boost/operators.hpp>
  8 | #include <boost/serialization/nvp.hpp>
  9 | #include <boost/serialization/access.hpp>
 10 | #include <boost/serialization/vector.hpp>
 11 | 
 12 | #include <gmpxx.h>
 13 | 
 14 | #include "random.hpp"
 15 | #include "serializations.hpp"
 16 | 
 17 | 
 18 | namespace she
 19 | {
 20 | 
 21 | class ParameterSet : boost::equality_comparable<ParameterSet>
 22 | {
 23 | public:
 24 |     ParameterSet(unsigned int security,
 25 |                  unsigned int noise_size_bits,
 26 |                  unsigned int private_key_size_bits,
 27 |                  unsigned int ciphertext_size_bits,
 28 |                  unsigned int prf_seed);
 29 | 
 30 |     ParameterSet() noexcept;
 31 | 
 32 |     unsigned int security;
 33 |     unsigned int noise_size_bits;
 34 |     unsigned int private_key_size_bits;
 35 |     unsigned int ciphertext_size_bits;
 36 |     unsigned int prf_seed;
 37 | 
 38 |     // Generate parameter set for given `security`, random prf `seed`, that allows to perform at least
 39 |     // `circuit_mult_size homomorphic multiplications on ciphertexts
 40 |     static const ParameterSet
 41 |     generate_parameter_set(unsigned int security, unsigned int circuit_mult_size, unsigned int seed);
 42 | 
 43 |     // Approximate number of homomorphic multiplications that can be performed
 44 |     unsigned int degree() const noexcept { return private_key_size_bits / noise_size_bits; }
 45 | 
 46 |     bool operator==(const ParameterSet &) const noexcept;
 47 | 
 48 |  private:
 49 |     friend class boost::serialization::access;
 50 | 
 51 |     template<class Archive>
 52 |     void serialize(Archive & ar, unsigned int const version)
 53 |     {
 54 |         ar & BOOST_SERIALIZATION_NVP(security);
 55 |         ar & BOOST_SERIALIZATION_NVP(noise_size_bits);
 56 |         ar & BOOST_SERIALIZATION_NVP(private_key_size_bits);
 57 |         ar & BOOST_SERIALIZATION_NVP(ciphertext_size_bits);
 58 |         ar & BOOST_SERIALIZATION_NVP(prf_seed);
 59 |     }
 60 | };
 61 | 
 62 | 
 63 | class CompressedCiphertext;
 64 | class EncryptedArray;
 65 | 
 66 | class PrivateKey : boost::equality_comparable<PrivateKey>
 67 | {
 68 |  public:
 69 |     // Constuct private from parameter set
 70 |     PrivateKey(const ParameterSet &) noexcept;
 71 | 
 72 |     // Empty ctor for deserialization purposes
 73 |     PrivateKey() noexcept {};
 74 | 
 75 |     // Produce a compressed ciphertext from a plaintext
 76 |     CompressedCiphertext encrypt(const std::vector<bool> & bits) const noexcept;
 77 | 
 78 |     // Decrypt an expanded ciphertext
 79 |     std::vector<bool> decrypt(const EncryptedArray &) const noexcept;
 80 | 
 81 |     const ParameterSet & parameter_set() const noexcept { return _parameter_set; };
 82 |     const mpz_class & private_element() const noexcept { return _private_element; }
 83 | 
 84 |     bool operator==(const PrivateKey &) const noexcept;
 85 | 
 86 |  private:
 87 |     ParameterSet _parameter_set;
 88 | 
 89 |     void initialize_random_generators() const noexcept;
 90 |     mutable std::unique_ptr<CSPRNG> _generator;
 91 |     mutable std::unique_ptr<PseudoRandomStream> _prf_stream;
 92 | 
 93 |     PrivateKey& generate_values() noexcept;
 94 |     mpz_class _private_element;
 95 | 
 96 |  private:
 97 |     friend class boost::serialization::access;
 98 | 
 99 |     template<class Archive>
100 |     void save(Archive & ar, unsigned int const version) const
101 |     {
102 |         ar & BOOST_SERIALIZATION_NVP(_parameter_set);
103 |         ar & BOOST_SERIALIZATION_NVP(_private_element);
104 |     }
105 | 
106 |     template<class Archive>
107 |     void load(Archive & ar, unsigned int const version)
108 |     {
109 |         ar & BOOST_SERIALIZATION_NVP(_parameter_set);
110 |         ar & BOOST_SERIALIZATION_NVP(_private_element);
111 | 
112 |         initialize_random_generators();
113 |     }
114 | 
115 |     BOOST_SERIALIZATION_SPLIT_MEMBER()
116 | };
117 | 
118 | 
119 | } // namespace she
120 | 


--------------------------------------------------------------------------------
/src/key.cpp:
--------------------------------------------------------------------------------
  1 | #include <cassert>
  2 | #include <random>
  3 | 
  4 | #include <iostream>
  5 | using std::cout;
  6 | using std::endl;
  7 | 
  8 | #include "she.hpp"
  9 | #include "she/defs.hpp"
 10 | #include "she/exceptions.hpp"
 11 | 
 12 | using std::random_device;
 13 | using std::vector;
 14 | 
 15 | 
 16 | namespace she
 17 | {
 18 |     ParameterSet::ParameterSet(unsigned int lambda,
 19 |                                unsigned int rho,
 20 |                                unsigned int eta,
 21 |                                unsigned int gamma,
 22 |                                unsigned int seed) :
 23 |       security(lambda),
 24 |       noise_size_bits(rho),
 25 |       private_key_size_bits(eta),
 26 |       ciphertext_size_bits(gamma),
 27 |       prf_seed(seed)
 28 |     {
 29 |         ASSERT((gamma >= eta) && (eta >= rho) && (rho > 0), "Bad parameters");
 30 |     }
 31 | 
 32 |     ParameterSet::ParameterSet() noexcept :
 33 |       security(1),
 34 |       noise_size_bits(1),
 35 |       private_key_size_bits(1),
 36 |       ciphertext_size_bits(1),
 37 |       prf_seed(1)
 38 |     {}
 39 | 
 40 |     const ParameterSet
 41 |     ParameterSet::generate_parameter_set(unsigned int security, unsigned int circuit_mult_size, unsigned int seed)
 42 |     {
 43 |         ASSERT(security > 0, "Security parameter should be greater than 0");
 44 |         ASSERT(circuit_mult_size > 0, "Multiplicative circuit size should be greater than 0");
 45 | 
 46 |         unsigned int rho = 2 * security,
 47 |                      eta = security * security + security * circuit_mult_size,
 48 |                      gamma = eta * eta * circuit_mult_size;
 49 | 
 50 |         return { security, rho, eta, gamma, seed };
 51 |     }
 52 | 
 53 |     bool ParameterSet::operator==(const ParameterSet& other) const
 54 |     noexcept
 55 |     {
 56 |         return (security == other.security)
 57 |             && (noise_size_bits == other.noise_size_bits)
 58 |             && (private_key_size_bits == other.private_key_size_bits)
 59 |             && (ciphertext_size_bits == other.ciphertext_size_bits)
 60 |             && (prf_seed == other.prf_seed);
 61 |     }
 62 | 
 63 | 
 64 |     PrivateKey::PrivateKey(const ParameterSet & parameter_set) noexcept :
 65 |       _parameter_set(parameter_set)
 66 |     {
 67 |         initialize_random_generators();
 68 |         generate_values();
 69 |     }
 70 | 
 71 |     bool PrivateKey::operator==(const PrivateKey & other) const noexcept
 72 |     {
 73 |         return (_parameter_set == other._parameter_set)
 74 |             && (_private_element == other._private_element);
 75 |     }
 76 | 
 77 |     PrivateKey& PrivateKey::generate_values() noexcept
 78 |     {
 79 |         // Generate odd eta-bit integer
 80 |         do {
 81 |             _private_element = _generator->get_bits(_parameter_set.private_key_size_bits);
 82 |         } while (_private_element % 2 == 0);
 83 | 
 84 |         // Generate random odd q from [1, 2^gamma / p)
 85 |         const mpz_class q_upper_bound = (mpz_class(1) << _parameter_set.ciphertext_size_bits)
 86 |                                       / _private_element;
 87 |         mpz_class q;
 88 |         do {
 89 |             q = _generator->get_range(q_upper_bound);
 90 |         } while (q % 2 == 0);
 91 | 
 92 |         return *this;
 93 |     }
 94 | 
 95 |     void PrivateKey::initialize_random_generators() const noexcept
 96 |     {
 97 |         _generator.reset(new CSPRNG);
 98 |         _prf_stream.reset(
 99 |             new PseudoRandomStream{_parameter_set.ciphertext_size_bits, _parameter_set.prf_seed});
100 |     }
101 | 
102 |     CompressedCiphertext PrivateKey::encrypt(const std::vector<bool> & bits) const noexcept
103 |     {
104 |         _prf_stream->reset();
105 | 
106 |         CompressedCiphertext result(_parameter_set);
107 | 
108 |         // Generate compressed public element
109 |         const mpz_class & prf_output = _prf_stream->next();
110 |         result._public_element_delta = prf_output % _private_element;
111 | 
112 |         for (const bool m : bits)
113 |         {
114 |             // Choose random noise
115 |             const mpz_class r = _generator->get_range_bits(_parameter_set.noise_size_bits) + 1;
116 | 
117 |             // Random PRF output
118 |             const mpz_class & prf_output = _prf_stream->next();
119 | 
120 |             // Add compressed ciphertext deltas
121 |             result._elements_deltas.push_back((prf_output - 2*r - m) % _private_element);
122 |         }
123 | 
124 |         return result;
125 |     }
126 | 
127 |     vector<bool> PrivateKey::decrypt(const EncryptedArray & array) const noexcept
128 |     {
129 |         _prf_stream->reset();
130 | 
131 |         vector<bool> result;
132 |         for (const mpz_class & element : array.elements())
133 |         {
134 |             const mpz_class m = element % _private_element % 2;
135 |             result.push_back(static_cast<bool>(m.get_si()));
136 |         }
137 |         return result;
138 |     }
139 | 
140 | } // namespace she
141 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
  1 | # libshe
  2 | 
  3 | [![Build Status](https://travis-ci.org/bogdan-kulynych/libshe.svg?branch=master)](https://travis-ci.org/bogdan-kulynych/libshe) [![Coverage Status](https://coveralls.io/repos/bogdan-kulynych/libshe/badge.svg?branch=master)](https://coveralls.io/r/bogdan-kulynych/libshe?branch=master)
  4 | 
  5 | Symmetric somewhat homomorphic encryption library based on DGHV scheme.
  6 | 
  7 | 
  8 | ## Introduction
  9 | 
 10 | Homomorphic encryption is a kind of encryption that allows to execute functions over the ciphertexts without decrypting them. This library implements a symmetric variant of originally asymmetric somewhat homomorphic encryption scheme over the integers by van Dijk et al. [DGHV10][DGHV10] using ciphertext compression techniques from [CNT11][CNT11]. The symmetricity of the scheme means that only the private key is used to encrypt and decrypt ciphertexts. A relatively small public element, however, is used in homomorphic operations, but it is not a real public key.
 11 | 
 12 | Such scheme is useful in secure function evaluation setting, where a client encrypts an input to an algorithm using their private key, sends it to a server which executes an algorithm homorphically, and sends the output back to the client. The client then obtains the output of the algorithm by decrypting server response using the private key.
 13 | 
 14 | See the following diagram for visual explanation.
 15 | 
 16 | - Let _f_ be an algorithm to be evaluated on a server.
 17 | - Let _a[1], a[2], ... a[n]_ be inputs of _f_ that client provides to the server.
 18 | - Let _b[1], b[2], ... b[n]_ be inputs of _f_ that server possesses.
 19 | - Let _p_ be the client's private key, and _x[0]_ be the corresponding public element
 20 | 
 21 | ![SFE](misc/sfe.png)
 22 | 
 23 | 
 24 | ## Status
 25 | 
 26 | _Warning_. This is experimental software. **It is not to be used in mission-critical applications.** Since the time this software was written, parameters of the underlying scheme were broken many times.
 27 | 
 28 | ## Installation
 29 | 
 30 | You can consult the `.travis.yml` for concrete installation commands on Debian-based systems.
 31 | 
 32 | ### Requirements
 33 | 
 34 | - gcc >= 4.8
 35 | - [boost](http://www.boost.org/) >= 1.55
 36 | - [GMP](https://gmplib.org/) >= 6.0.0
 37 | - [lcov](http://ltp.sourceforge.net/coverage/lcov/readme.php) >= 1.11 (optional)
 38 | 
 39 | ### Building and installation
 40 | 
 41 | Build and install `libshe.so` library and headers:
 42 | 
 43 | ```
 44 | make
 45 | sudo make install
 46 | ```
 47 | 
 48 | You can also uninstall with
 49 | 
 50 | ```
 51 | sudo make uninstall
 52 | ```
 53 | 
 54 | ## Usage
 55 | 
 56 | ### Tests and benchmarks
 57 | 
 58 | Run tests:
 59 | 
 60 | ```
 61 | make tests
 62 | ```
 63 | 
 64 | _Note_. Running tests will compile sources with debug options. Do `make clean` before installing if tests were run previously.
 65 | 
 66 | Run benchmarks:
 67 | 
 68 | ```
 69 | make benchmarks
 70 | ```
 71 | 
 72 | ### Building your program
 73 | 
 74 | Use C++11 and link against _GMP_ and _Boost Serialization_ when building your program:
 75 | 
 76 | ```
 77 | -std=c++11 -lgmp -lboost_serialization -lshe
 78 | ```
 79 | 
 80 | Include libshe in your sources:
 81 | 
 82 | ```cpp
 83 | #include <she.hpp>
 84 | 
 85 | using she::ParameterSet;
 86 | using she::PrivateKey;
 87 | // ...
 88 | ```
 89 | 
 90 | ### Example
 91 | 
 92 | The following example assumes a client and a server that are engaged in a two-party secure function evaluation protocol.
 93 | 
 94 | Client generates a parameter set:
 95 | 
 96 | ```cpp
 97 | const ParameterSet params = ParameterSet::generate_parameter_set(62, 1, 42);
 98 | ```
 99 | 
100 | Given these parameters, the encryption scheme exhibits following properties:
101 | 
102 |    - Security level is **(62-bit)**
103 |    - At least 1 multiplication can be evaluated on every bit in the ciphertext
104 |    - The non-secure random number generator used in ciphertext compression is seeded with number 42
105 | 
106 | Client then constructs a private key object from generated parameters:
107 | 
108 | ```cpp
109 | const PrivateKey sk(params);
110 | ```
111 | 
112 | Encrypts the plaintext:
113 | 
114 | ```cpp
115 | const vector<bool> plaintext = {1, 0, 1, 0, 1, 0, 1, 0};
116 | const auto compressed_ciphertext = sk.encrypt(plaintext);
117 | ```
118 | 
119 | Serializes and sends compressed ciphertext to server.
120 | 
121 | Upon obtaining the compressed ciphertext, Server expands it to perform operations:
122 | 
123 | ```cpp
124 | const auto ciphertext = compressed_ciphertext.expand();
125 | ```
126 | 
127 | Executes the algorithm (here negation of an 8-bit input)
128 | 
129 | ```cpp
130 | const vector<bool> another_plaintext = {1, 1, 1, 1, 1, 1, 1, 1};
131 | const auto response = ciphertext ^ another_plaintext;
132 | ```
133 | 
134 | Serializes the output and sends it back to the client.
135 | 
136 | Client decrypts the response and obtains the algorithm output in plaintext:
137 | 
138 | ```cpp
139 | const auto decrypted_response = sk.decrypt(response);
140 | const vector<bool> expected_result = {0, 1, 0, 1, 0, 1, 0, 1};
141 | assert(decrypted_response == expected_result);
142 | ```
143 | 
144 | Note that ciphertext can be compressed only during encryption on the client side, so cost for Server → Client communication is significantly higher than that of Client → Server communication.
145 | 
146 | ### Available homomorphic operations
147 | 
148 | - Bitwise addition (XOR): `c1 ^ c2`
149 | - Bitwise multiplication (AND): `c1 & c2`
150 | - Equality comparison: `c0.equal({c1, c2, ..., cn})`..
151 | - Selection of _i_-th ciphertext: `c0.select({c1, c2, ..., cn})`.
152 | 
153 | ## License
154 | 
155 | The code is released under the [GNU General Public License v3.0](https://www.gnu.org/licenses/gpl-3.0.html).
156 | 
157 | Copyright © 2015 Bogdan Kulynych. `hello [at] bogdankulynych.me`
158 | 
159 | 
160 | 
161 | [DGHV10]: http://eprint.iacr.org/2009/616.pdf
162 | [CNT11]: http://eprint.iacr.org/2011/440.pdf
163 | 


--------------------------------------------------------------------------------
/tests/test_key.cpp:
--------------------------------------------------------------------------------
  1 | #define BOOST_TEST_DYN_LINK
  2 | #define BOOST_TEST_MODULE KeyModule
  3 | #include <cstddef>
  4 | #include <boost/test/unit_test.hpp>
  5 | 
  6 | #include "she.hpp"
  7 | #include "she/exceptions.hpp"
  8 | #include "serialization_formats.hpp"
  9 | 
 10 | using std::abs;
 11 | using std::stringstream;
 12 | using std::vector;
 13 | 
 14 | using she::precondition_not_satisfied;
 15 | using she::ParameterSet;
 16 | using she::PrivateKey;
 17 | 
 18 | 
 19 | BOOST_AUTO_TEST_SUITE(ParameterSetSuite)
 20 | 
 21 | 
 22 | BOOST_AUTO_TEST_CASE(parameter_set_construction)
 23 | {
 24 |     {
 25 |         BOOST_CHECK_THROW(ParameterSet(42, 1000, 100, 10000, 5), precondition_not_satisfied);
 26 |         BOOST_CHECK_THROW(ParameterSet(42, 100, 1000, 999, 5), precondition_not_satisfied);
 27 |         BOOST_CHECK_THROW(ParameterSet(42, 0, 1, 2, 5), precondition_not_satisfied);
 28 |     }
 29 | 
 30 |     {
 31 |         const ParameterSet params { 42, 100, 1000, 100000, 5 };
 32 |         BOOST_CHECK_EQUAL(params.security, 42);
 33 |         BOOST_CHECK_EQUAL(params.noise_size_bits, 100);
 34 |         BOOST_CHECK_EQUAL(params.private_key_size_bits, 1000);
 35 |         BOOST_CHECK_EQUAL(params.ciphertext_size_bits, 100000);
 36 |         BOOST_CHECK_EQUAL(params.prf_seed, 5);
 37 |     }
 38 | }
 39 | 
 40 | BOOST_AUTO_TEST_CASE(parameter_set_generation)
 41 | {
 42 |     {
 43 |         BOOST_CHECK_THROW(ParameterSet::generate_parameter_set(0, 0, 42),
 44 |             precondition_not_satisfied);
 45 |         BOOST_CHECK_THROW(ParameterSet::generate_parameter_set(0, 1, 42),
 46 |             precondition_not_satisfied);
 47 |         BOOST_CHECK_THROW(ParameterSet::generate_parameter_set(1, 0, 42),
 48 |             precondition_not_satisfied);
 49 |     }
 50 | 
 51 |     {
 52 |         const unsigned int security = 42;
 53 |         const unsigned int circuit_mult_size = 20;
 54 |         const ParameterSet params = ParameterSet::generate_parameter_set(security, circuit_mult_size, 42);
 55 | 
 56 |         BOOST_CHECK_EQUAL(
 57 |           params.security,
 58 |           security
 59 |         );
 60 | 
 61 |         BOOST_CHECK_EQUAL(
 62 |           params.noise_size_bits,
 63 |           2 * security
 64 |         );
 65 | 
 66 |         BOOST_CHECK_EQUAL(
 67 |           params.private_key_size_bits,
 68 |           security * security + security * circuit_mult_size
 69 |         );
 70 | 
 71 |         BOOST_CHECK_EQUAL(
 72 |           params.ciphertext_size_bits,
 73 |           params.private_key_size_bits * params.private_key_size_bits * circuit_mult_size
 74 |         );
 75 | 
 76 |         BOOST_CHECK_GT(
 77 |           params.degree() - 1,
 78 |           circuit_mult_size
 79 |         );
 80 |     }
 81 | }
 82 | 
 83 | BOOST_AUTO_TEST_CASE(parameter_set_equality_comparison)
 84 | {
 85 |     const ParameterSet a { 42, 100, 1000, 100000, 5 };
 86 |     const ParameterSet b { 42, 100, 1000, 100000, 5 };
 87 |     const ParameterSet c { 72, 100, 1000, 100000, 5 };
 88 | 
 89 |     BOOST_CHECK(a == b);
 90 |     BOOST_CHECK(b != c);
 91 |     BOOST_CHECK(c != a);
 92 | }
 93 | 
 94 | BOOST_AUTO_TEST_CASE_TEMPLATE(parameter_set_serialization, Format, Formats)
 95 | {
 96 |     const ParameterSet params { 42, 100, 1000, 100000, 5 };
 97 |     ParameterSet restored_params {};
 98 | 
 99 |     stringstream ss;
100 |     {
101 |         typename Format::oarchive oa(ss);
102 |         oa << BOOST_SERIALIZATION_NVP(params);
103 |     }
104 |     {
105 |         typename Format::iarchive ia(ss);
106 |         ia >> BOOST_SERIALIZATION_NVP(restored_params);
107 |     }
108 | 
109 |     BOOST_CHECK(params == restored_params);
110 | }
111 | 
112 | BOOST_AUTO_TEST_SUITE_END()
113 | 
114 | 
115 | BOOST_AUTO_TEST_SUITE(PrivateKeySuite)
116 | 
117 | BOOST_AUTO_TEST_CASE(private_key_construction_accessors_and_comparison)
118 | {
119 |     const auto params = ParameterSet::generate_parameter_set(42, 10, 42);
120 |     const PrivateKey sk(params);
121 | 
122 |     BOOST_CHECK(sk.parameter_set() == params);
123 |     const auto private_element_size = mpz_sizeinbase(sk.private_element().get_mpz_t(), 2);
124 |     // BOOST_CHECK_EQUAL(private_element_size, params.private_key_size_bits);
125 | 
126 |     // These should not be the same, because new private key elements are generated every time
127 |     const PrivateKey other_sk(params);
128 |     BOOST_CHECK(sk != other_sk);
129 |     BOOST_CHECK(!(sk == other_sk));
130 | }
131 | 
132 | BOOST_AUTO_TEST_CASE(private_key_encryption)
133 | {
134 |     const auto params = ParameterSet::generate_parameter_set(42, 5, 42);
135 |     const PrivateKey sk(params);
136 | 
137 |     {
138 |         sk.encrypt({});
139 |     }
140 | 
141 |     {
142 |         sk.encrypt({1, 0, 0, 0});
143 |     }
144 | }
145 | 
146 | BOOST_AUTO_TEST_CASE(private_key_encryption_decryption)
147 | {
148 |     const auto params = ParameterSet::generate_parameter_set(42, 5, 42);
149 |     const PrivateKey sk(params);
150 | 
151 |     const size_t iterations = 15;
152 | 
153 |     const vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 0};
154 |     unsigned int successful_recoveries = 0;
155 |     for (size_t i = 0; i < iterations; ++i)
156 |     {
157 |         const auto ciphertext = sk.encrypt(plaintext);
158 |         const auto restored_plaintext = sk.decrypt(ciphertext.expand());
159 |         if(restored_plaintext == plaintext) {
160 |             ++successful_recoveries;
161 |         }
162 |     }
163 | 
164 |     BOOST_CHECK_EQUAL(successful_recoveries, iterations);
165 | }
166 | 
167 | BOOST_AUTO_TEST_CASE_TEMPLATE(private_key_serialization, Format, Formats)
168 | {
169 |     const auto params = ParameterSet::generate_parameter_set(42, 5, 42);
170 |     const PrivateKey sk(params);
171 |     PrivateKey restored_sk;
172 | 
173 |     stringstream ss;
174 |     {
175 |         typename Format::oarchive oa(ss);
176 |         oa << BOOST_SERIALIZATION_NVP(sk);
177 |     }
178 |     {
179 |         typename Format::iarchive ia(ss);
180 |         ia >> BOOST_SERIALIZATION_NVP(restored_sk);
181 |     }
182 | 
183 |     BOOST_CHECK(sk == restored_sk);
184 | }
185 | 
186 | BOOST_AUTO_TEST_SUITE_END()
187 | 


--------------------------------------------------------------------------------
/benchmarks/pir.cpp:
--------------------------------------------------------------------------------
  1 | #include <ctime>
  2 | #include <cstdlib>
  3 | #include <iostream>
  4 | #include <random>
  5 | #include <memory>
  6 | 
  7 | #include "she.hpp"
  8 | #include "utils.hpp"
  9 | 
 10 | using std::cout;
 11 | using std::endl;
 12 | using std::boolalpha;
 13 | using std::vector;
 14 | using std::unique_ptr;
 15 | using std::move;
 16 | 
 17 | using she::PrivateKey;
 18 | using she::ParameterSet;
 19 | using she::CompressedCiphertext;
 20 | using she::EncryptedArray;
 21 | using she::PlaintextArray;
 22 | 
 23 | 
 24 | vector<bool> dec_to_bits(unsigned int num, unsigned int bit_size)
 25 | {
 26 |     vector<bool> result;
 27 |     for (int i = bit_size - 1; i >= 0; --i) {
 28 |         result.push_back((num >> i) & 1);
 29 |     }
 30 |     return result;
 31 | }
 32 | 
 33 | vector<bool> random_bits(unsigned int bit_size)
 34 | {
 35 |     vector<bool> result {};
 36 |     for (unsigned int i = 0; i < bit_size; ++i) {
 37 |         bool random_bit = rand() % 2;
 38 |         result.push_back(random_bit);
 39 |     }
 40 | 
 41 |     return result;
 42 | }
 43 | 
 44 | void
 45 | randomly_populate_database( vector<PlaintextArray> * database
 46 |                           , unsigned int database_size
 47 |                           , unsigned int record_size)
 48 | {
 49 |     for (unsigned int i = 0; i < database_size; ++i) {
 50 |         database->push_back(PlaintextArray(random_bits(record_size)));
 51 |     }
 52 | }
 53 | 
 54 | void build_database_indexes( vector<PlaintextArray> * database_indexes
 55 |                          , unsigned int database_size
 56 |                          , unsigned int index_size)
 57 | {
 58 |     for (unsigned int i = 0; i < database_size; ++i) {
 59 |         database_indexes->push_back(dec_to_bits(i, index_size));
 60 |     }
 61 | }
 62 | 
 63 | PrivateKey generate_key( unsigned int security
 64 |                        , unsigned int record_size)
 65 | {
 66 |     START_TIMER("KEY GENERATION", "CLIENT");
 67 | 
 68 |     const auto params = ParameterSet::generate_parameter_set(security, record_size, 42);
 69 |     auto result = PrivateKey(params);
 70 | 
 71 |     END_TIMER();
 72 | 
 73 |     return result;
 74 | }
 75 | 
 76 | CompressedCiphertext
 77 | generate_query( const PrivateKey & sk
 78 |               , const vector<bool> & index_bits)
 79 | {
 80 |     START_TIMER("QUERY GENERATION", "CLIENT");
 81 | 
 82 |     auto result = sk.encrypt(index_bits);
 83 | 
 84 |     END_TIMER();
 85 |     return result;
 86 | }
 87 | 
 88 | EncryptedArray expand_ciphertext(const CompressedCiphertext & ctxt)
 89 | {
 90 |     START_TIMER("QUERY CIPHERTEXT EXPANSION", "SERVER");
 91 | 
 92 |     auto result = ctxt.expand();
 93 | 
 94 |     END_TIMER();
 95 |     return result;
 96 | }
 97 | 
 98 | EncryptedArray
 99 | calculate_selection_vector( const EncryptedArray & query
100 |                           , const vector<PlaintextArray> & database_indexes)
101 | {
102 |     START_TIMER("SELECTION VECTOR HOMOMORPHIC CALCULATION", "SERVER");
103 | 
104 |     auto result = query.equal(database_indexes);
105 | 
106 |     END_TIMER();
107 |     return result;
108 | }
109 | 
110 | EncryptedArray
111 | calculate_response( const EncryptedArray & sv
112 |                   , const vector<PlaintextArray> & database)
113 | {
114 |     START_TIMER("RESPONSE HOMOMORPHIC CALCULATION", "SERVER");
115 | 
116 |     auto result = sv.select(database);
117 | 
118 |     END_TIMER();
119 |     return result;
120 | }
121 | 
122 | PlaintextArray
123 | decrypt_response( const PrivateKey & sk
124 |                   , const EncryptedArray & response)
125 | {
126 |     START_TIMER("RESPONSE DECRYPTION", "CLIENT");
127 | 
128 |     auto result = sk.decrypt(response);
129 | 
130 |     END_TIMER();
131 |     return result;
132 | }
133 | 
134 | 
135 | int main()
136 | {
137 |     srand (time(NULL));
138 | 
139 |     // Security level. 62 for 62-bit security
140 |     unsigned int security = 62;
141 | 
142 |     // Number of records in a database
143 |     unsigned int database_size = 16;
144 | 
145 |     // Size of every record in bits (note that in general sizes can vary)
146 |     unsigned int record_size = 64;
147 | 
148 |     // Size of database index in bits.
149 |     // To avoid problems should be equal to floor(log2(database_size) + 1
150 |     unsigned int index_size = 4;
151 | 
152 |     cout << "Security:      " << security << endl;
153 |     cout << "Database size: " << database_size << endl;
154 |     cout << "Record size:   " << record_size << endl;
155 |     cout << "Index size:    " << index_size << endl << endl;
156 | 
157 |     // Preparation: Generate random database
158 |     vector<PlaintextArray> database;
159 |     randomly_populate_database(&database, database_size, record_size);
160 | 
161 |     // Preparation: Generate database indexes
162 |     vector<PlaintextArray> database_indexes;
163 |     build_database_indexes(&database_indexes, database_size, index_size);
164 | 
165 |     // Generate key
166 |     const auto sk = move(generate_key(security, index_size));
167 | 
168 |     // Pick random index and generate compressed query ciphertext
169 |     // This is the slowest part. Should consider options to move it to client side.
170 |     const auto index = rand() % database_size;
171 |     const auto compressed_ciphertext = move(generate_query(sk, dec_to_bits(index, index_size)));
172 | 
173 |     // Expand the compressed ciphertext
174 |     const auto encrypted_query = move(expand_ciphertext(compressed_ciphertext));
175 | 
176 |     // Calculate homomorphic selection vector
177 |     const auto selector = move(calculate_selection_vector(encrypted_query, database_indexes));
178 | 
179 |     // Homomorphically calculate response
180 |     const auto encrypted_response = move(calculate_response(selector, database));
181 | 
182 |     // Decrypt response
183 |     std::vector<bool> response = move(decrypt_response(sk, encrypted_response));
184 | 
185 |     TIMER_STATS();
186 | 
187 |     // Show response if it is small enough
188 |     if (record_size < 80) {
189 |         cout << "Queried database index:" << endl;
190 |         for (const auto & bit : database[index].elements()) {
191 |             cout << bit;
192 |         }
193 |         cout << endl;
194 | 
195 |         cout << "Obtained result:" << endl;
196 |         for (const auto & bit : response) {
197 |             cout << bit;
198 |         }
199 |         cout << endl;
200 |     }
201 | 
202 |     cout << "Correct result? " << boolalpha << (database[index] == response) << endl;
203 | 
204 |     return 0;
205 | }


--------------------------------------------------------------------------------
/include/she/ciphertext.hpp:
--------------------------------------------------------------------------------
  1 | #pragma once
  2 | 
  3 | #include <cstddef>
  4 | #include <set>
  5 | #include <vector>
  6 | #include <memory>
  7 | 
  8 | #include <boost/operators.hpp>
  9 | #include <boost/serialization/nvp.hpp>
 10 | #include <boost/serialization/access.hpp>
 11 | #include <boost/serialization/vector.hpp>
 12 | #include <boost/serialization/split_free.hpp>
 13 | 
 14 | #include <gmpxx.h>
 15 | 
 16 | #include "key.hpp"
 17 | #include "random.hpp"
 18 | #include "serializations.hpp"
 19 | 
 20 | 
 21 | namespace she
 22 | {
 23 | 
 24 | class PrivateKey;
 25 | class PlaintextArray;
 26 | 
 27 | class EncryptedArray : boost::equality_comparable<EncryptedArray
 28 |                      , boost::xorable<EncryptedArray
 29 |                      , boost::xorable<EncryptedArray, PlaintextArray
 30 |                      , boost::andable<EncryptedArray
 31 |                      , boost::andable<EncryptedArray, PlaintextArray
 32 |                      > > > > >
 33 | {
 34 |  friend class PlaintextArray;
 35 |  friend class CompressedCiphertext;
 36 |  public:
 37 |     // Construct empty ciphertext with given public element
 38 |     EncryptedArray(const mpz_class & x, unsigned int max_degree, unsigned int degree=1) noexcept;
 39 | 
 40 |     // Empty ctor for deserialization purposes
 41 |     EncryptedArray() noexcept {};
 42 | 
 43 |     // Homomorphic element-wise addition (XOR)
 44 |     EncryptedArray & operator^=(const PlaintextArray &) noexcept;
 45 |     EncryptedArray & operator^=(const EncryptedArray &) noexcept;
 46 | 
 47 |     // Homomorphic element-wise multiplication (AND)
 48 |     EncryptedArray & operator&=(const PlaintextArray &) noexcept;
 49 |     EncryptedArray & operator&=(const EncryptedArray &) noexcept;
 50 | 
 51 |     // Homomorphic equality comparison
 52 |     const EncryptedArray equal(const std::vector<PlaintextArray> &) const noexcept;
 53 |     const EncryptedArray equal(const std::vector<EncryptedArray> &) const noexcept;
 54 | 
 55 |     // Homomorphic select function
 56 |     const EncryptedArray select(const std::vector<PlaintextArray> &) const noexcept;
 57 |     const EncryptedArray select(const std::vector<EncryptedArray> &) const noexcept;
 58 | 
 59 |     // Extend array
 60 |     EncryptedArray & extend(const EncryptedArray & other) noexcept;
 61 | 
 62 |     // Reflects how noisy the ciphertexts, equals the number of homomorphic multiplications performed since encryption
 63 |     unsigned int degree() const noexcept { return _degree; }
 64 | 
 65 |     // Approximate maximum number of homomorphic multiplications
 66 |     unsigned int max_degree() const noexcept { return _max_degree; }
 67 | 
 68 |     // Ciphertext size
 69 |     size_t size() const noexcept { return _elements.size(); }
 70 | 
 71 |     // Encrypted bits
 72 |     const std::vector<mpz_class>& elements() const noexcept { return _elements; }
 73 |     std::vector<mpz_class>& elements() noexcept { return _elements; }
 74 | 
 75 |     // Public element used in homomorphic operations
 76 |     const mpz_class & public_element() const noexcept;
 77 | 
 78 |     // Representation comparison (non-homomorphic)
 79 |     bool operator==(const EncryptedArray &) const noexcept;
 80 | 
 81 |  private:
 82 |     unsigned int _degree;
 83 |     unsigned int _max_degree;
 84 | 
 85 |     std::vector<mpz_class> _elements;
 86 | 
 87 |     void set_public_element(const mpz_class & x) noexcept;
 88 |     static std::set<mpz_class> public_elements;
 89 |     typename std::set<mpz_class>::const_iterator _public_element_ptr;
 90 | 
 91 |     bool _initialized;
 92 | 
 93 |  private:
 94 |     friend class boost::serialization::access;
 95 | 
 96 |     template<class Archive>
 97 |     void save(Archive & ar, unsigned int const version) const
 98 |     {
 99 |         ar & BOOST_SERIALIZATION_NVP(_degree);
100 |         ar & BOOST_SERIALIZATION_NVP(_max_degree);
101 |         ar & BOOST_SERIALIZATION_NVP(_elements);
102 |         ar & boost::serialization::make_nvp("_public_element", *_public_element_ptr);
103 |     }
104 | 
105 |     template<class Archive>
106 |     void load(Archive & ar, unsigned int const version)
107 |     {
108 | 
109 |         ar & BOOST_SERIALIZATION_NVP(_degree);
110 |         ar & BOOST_SERIALIZATION_NVP(_max_degree);
111 |         ar & BOOST_SERIALIZATION_NVP(_elements);
112 | 
113 |         mpz_class x;
114 |         ar & boost::serialization::make_nvp("_public_element", x);
115 |         set_public_element(x);
116 |     }
117 | 
118 |     BOOST_SERIALIZATION_SPLIT_MEMBER()
119 | };
120 | 
121 | 
122 | class CompressedCiphertext : boost::equality_comparable<CompressedCiphertext>
123 | {
124 |  friend class PrivateKey;
125 |  public:
126 |     // Empty ctor for deserialization purposes
127 |     CompressedCiphertext() noexcept {};
128 | 
129 |     // Expand ciphertext
130 |     EncryptedArray expand() const noexcept;
131 | 
132 |     // Ciphertext size
133 |     size_t size() const noexcept { return _elements_deltas.size(); }
134 | 
135 |     // Compressions of encrypted bits
136 |     const std::vector<mpz_class> & elements_deltas() const noexcept { return _elements_deltas; }
137 |     const mpz_class & public_element_delta() const noexcept { return _public_element_delta; }
138 | 
139 |     // Representation comparison
140 |     bool operator== (const CompressedCiphertext &) const noexcept;
141 | 
142 |  private:
143 |     CompressedCiphertext(const ParameterSet & params) noexcept;
144 | 
145 |     ParameterSet _parameter_set;
146 | 
147 |     void initialize_prf_stream() const noexcept;
148 |     mutable std::unique_ptr<PseudoRandomStream> _prf_stream;
149 | 
150 |     std::vector<mpz_class> _elements_deltas;
151 |     mpz_class _public_element_delta;
152 | 
153 |  private:
154 |     friend class boost::serialization::access;
155 | 
156 |     template<class Archive>
157 |     void save(Archive & ar, unsigned int const version) const
158 |     {
159 |         ar & BOOST_SERIALIZATION_NVP(_parameter_set);
160 |         ar & BOOST_SERIALIZATION_NVP(_elements_deltas);
161 |         ar & BOOST_SERIALIZATION_NVP(_public_element_delta);
162 |     }
163 | 
164 |     template<class Archive>
165 |     void load(Archive & ar, unsigned int const version)
166 |     {
167 |         ar & BOOST_SERIALIZATION_NVP(_parameter_set);
168 |         ar & BOOST_SERIALIZATION_NVP(_elements_deltas);
169 |         ar & BOOST_SERIALIZATION_NVP(_public_element_delta);
170 | 
171 |         initialize_prf_stream();
172 |     }
173 | 
174 |     BOOST_SERIALIZATION_SPLIT_MEMBER()
175 | };
176 | 
177 | 
178 | // Homomorphic addition (XOR)
179 | PlaintextArray sum(const std::vector<PlaintextArray> &) noexcept;
180 | EncryptedArray sum(const std::vector<EncryptedArray> &) noexcept;
181 | 
182 | // Homomorphic multiplication (AND)
183 | PlaintextArray product(const std::vector<PlaintextArray> &) noexcept;
184 | EncryptedArray product(const std::vector<EncryptedArray> &) noexcept;
185 | 
186 | // Arrays concatenation
187 | PlaintextArray concat(const std::vector<PlaintextArray> &) noexcept;
188 | EncryptedArray concat(const std::vector<EncryptedArray> &) noexcept;
189 | 
190 | 
191 | } // namespace she
192 | 


--------------------------------------------------------------------------------
/tests/test_ciphertext.cpp:
--------------------------------------------------------------------------------
  1 | #define BOOST_TEST_DYN_LINK
  2 | #define BOOST_TEST_MODULE CiphertextModule
  3 | #include <cstddef>
  4 | #include <boost/test/unit_test.hpp>
  5 | 
  6 | #include "she.hpp"
  7 | #include "serialization_formats.hpp"
  8 | 
  9 | using std::stringstream;
 10 | using std::vector;
 11 | 
 12 | using she::PrivateKey;
 13 | using she::ParameterSet;
 14 | using she::CompressedCiphertext;
 15 | using she::PlaintextArray;
 16 | using she::EncryptedArray;
 17 | 
 18 | 
 19 | BOOST_AUTO_TEST_SUITE(CompressedCiphertextSuite)
 20 | 
 21 | BOOST_AUTO_TEST_CASE(compressed_ciphertext_construction_accessors_and_comparison)
 22 | {
 23 |     const PrivateKey sk(ParameterSet::generate_parameter_set(42, 10, 42));
 24 |     vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 25 | 
 26 |     {
 27 |         const auto compressed_ciphertext = sk.encrypt(plaintext);
 28 | 
 29 |         BOOST_CHECK_EQUAL(compressed_ciphertext.size(), plaintext.size());
 30 |         BOOST_CHECK_EQUAL(compressed_ciphertext.elements_deltas().size(), plaintext.size());
 31 |         BOOST_CHECK(compressed_ciphertext.public_element_delta() < sk.private_element());
 32 |     }
 33 | 
 34 |     {
 35 |         // These should be different, because new noises are generated on every encryption
 36 |         const auto c1 = sk.encrypt(plaintext);
 37 |         const auto c2 = sk.encrypt(plaintext);
 38 |         BOOST_CHECK(c1 != c2);
 39 |         BOOST_CHECK(!(c1 == c2));
 40 |     }
 41 | }
 42 | 
 43 | BOOST_AUTO_TEST_CASE(compressed_ciphertext_correct_expansion)
 44 | {
 45 |     const PrivateKey sk(ParameterSet::generate_parameter_set(42, 5, 42));
 46 |     const vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 47 |     const auto compressed_ciphertext = sk.encrypt(plaintext);
 48 |     const auto expanded_ciphertext = compressed_ciphertext.expand();
 49 |     const auto restored_plaintext = sk.decrypt(expanded_ciphertext);
 50 | 
 51 |     BOOST_CHECK(expanded_ciphertext.public_element() % sk.private_element() == 0);
 52 |     BOOST_CHECK_EQUAL(restored_plaintext.size(), plaintext.size());
 53 | }
 54 | 
 55 | BOOST_AUTO_TEST_CASE_TEMPLATE(compressed_ciphertext_serialization, Format, Formats)
 56 | {
 57 |     const PrivateKey sk(ParameterSet::generate_parameter_set(42, 10, 42));
 58 |     const auto ciphertext = sk.encrypt({1, 0, 1, 0, 1, 1, 1, 1});
 59 | 
 60 |     CompressedCiphertext restored_ciphertext;
 61 | 
 62 |     stringstream ss;
 63 |     {
 64 |         typename Format::oarchive oa(ss);
 65 |         oa << BOOST_SERIALIZATION_NVP(ciphertext);
 66 |     }
 67 |     {
 68 |         typename Format::iarchive ia(ss);
 69 |         ia >> BOOST_SERIALIZATION_NVP(restored_ciphertext);
 70 |     }
 71 | 
 72 |     BOOST_CHECK(ciphertext == restored_ciphertext);
 73 | }
 74 | 
 75 | BOOST_AUTO_TEST_SUITE_END()
 76 | 
 77 | 
 78 | BOOST_AUTO_TEST_SUITE(EncryptedArraySuite)
 79 | 
 80 | BOOST_AUTO_TEST_CASE(encrypted_array_construction_from_encryption)
 81 | {
 82 |     const vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 83 | 
 84 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 10, 42));
 85 | 
 86 |     const auto compressed_ciphertext = sk.encrypt(plaintext);
 87 |     const auto a1 = compressed_ciphertext.expand();
 88 | 
 89 |     BOOST_CHECK_EQUAL(a1.size(), plaintext.size());
 90 |     BOOST_CHECK_EQUAL(a1.elements().size(), plaintext.size());
 91 |     BOOST_CHECK_EQUAL(a1.degree(), 1);
 92 |     BOOST_CHECK_EQUAL(a1.max_degree(), sk.parameter_set().degree());
 93 |     BOOST_CHECK(a1.public_element() % sk.private_element() == 0);
 94 | }
 95 | 
 96 | BOOST_AUTO_TEST_CASE(encrypted_array_comparison)
 97 | {
 98 |     const vector<bool> plaintext = {1, 0, 1, 0, 1, 1, 1, 1};
 99 | 
100 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 10, 42));
101 | 
102 |     const auto c1 = sk.encrypt(plaintext);
103 |     const auto c2 = sk.encrypt(plaintext);
104 |     const auto a1 = c1.expand();
105 |     const auto a2 = c2.expand();
106 | 
107 |     BOOST_CHECK_EQUAL(a1.size(), a2.size());
108 |     BOOST_CHECK_EQUAL(a1.elements().size(), a2.elements().size());
109 |     BOOST_CHECK_EQUAL(a1.degree(), a2.degree());
110 |     BOOST_CHECK_EQUAL(a1.max_degree(), a2.max_degree());
111 |     BOOST_CHECK(a1.public_element() % sk.private_element() == 0);
112 |     BOOST_CHECK(a2.public_element() % sk.private_element() == 0);
113 | 
114 |     BOOST_CHECK(a1 != a2);
115 |     BOOST_CHECK(!(a1 == a2));
116 | }
117 | 
118 | BOOST_AUTO_TEST_CASE(encrypted_array_empty_construction)
119 | {
120 |     const mpz_class x = 42;
121 |     const EncryptedArray a1(x, 10);
122 | 
123 |     BOOST_CHECK_EQUAL(a1.size(), 0);
124 |     BOOST_CHECK_EQUAL(a1.elements().size(), 0);
125 |     BOOST_CHECK_EQUAL(a1.degree(), 1);
126 |     BOOST_CHECK(a1.public_element() == x);
127 | 
128 |     const EncryptedArray a2(x, 10);
129 |     BOOST_CHECK(a1 == a2);
130 |     BOOST_CHECK(!(a1 != a2));
131 | }
132 | 
133 | BOOST_AUTO_TEST_CASE_TEMPLATE(encrypted_array_serialization, Format, Formats)
134 | {
135 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
136 |     const auto array = sk.encrypt({1, 0, 1, 0, 1, 1, 1, 1}).expand();
137 | 
138 |     EncryptedArray restored_array;
139 | 
140 |     stringstream ss;
141 |     {
142 |         typename Format::oarchive oa(ss);
143 |         oa << BOOST_SERIALIZATION_NVP(array);
144 |     }
145 |     {
146 |         typename Format::iarchive ia(ss);
147 |         ia >> BOOST_SERIALIZATION_NVP(restored_array);
148 |     }
149 | 
150 |     BOOST_CHECK(array == restored_array);
151 | }
152 | 
153 | BOOST_AUTO_TEST_CASE(encrypted_arrays_extend_empty)
154 | {
155 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
156 | 
157 |     auto array = sk.encrypt({}).expand();
158 |     const auto plaintext = PlaintextArray({1, 1, 1, 1});
159 |     const auto ciphertext = sk.encrypt(plaintext).expand();
160 |     array.extend(ciphertext);
161 | 
162 |     BOOST_CHECK(sk.decrypt(array) == plaintext.elements());
163 | }
164 | 
165 | BOOST_AUTO_TEST_CASE(encrypted_arrays_concatenation_empty)
166 | {
167 |     const auto expected_result = PlaintextArray({1, 1, 0, 0, 0, 0, 1, 1});
168 | 
169 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 10, 42));
170 | 
171 |     auto array = sk.encrypt({1, 1, 0, 0}).expand();
172 |     const auto ciphertext = sk.encrypt({0, 0, 1, 1}).expand();
173 |     array.extend(ciphertext);
174 | 
175 |     BOOST_CHECK(sk.decrypt(array) == expected_result.elements());
176 | }
177 | 
178 | BOOST_AUTO_TEST_CASE(encrypted_arrays_concat)
179 | {
180 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
181 | 
182 |     const vector< vector<bool>> raw_plaintext_inputs = {
183 |         {0, 1, 0, 1},
184 |         {1, 0, 1, 0},
185 |         {0, 0, 0, 0},
186 |         {1, 1, 1, 1}
187 |     };
188 | 
189 |     vector<EncryptedArray> encrypted_inputs;
190 |     for (const auto & raw_plaintext_input : raw_plaintext_inputs) {
191 |         encrypted_inputs.push_back(sk.encrypt(raw_plaintext_input).expand());
192 |     }
193 | 
194 |     const auto expected_result = PlaintextArray({0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1});
195 |     auto concatenated = concat(encrypted_inputs);
196 | 
197 |     BOOST_CHECK(sk.decrypt(concatenated) == expected_result.elements());
198 | }
199 | 
200 | BOOST_AUTO_TEST_SUITE_END()


--------------------------------------------------------------------------------
/tests/test_homomorphic_operations.cpp:
--------------------------------------------------------------------------------
  1 | #define BOOST_TEST_DYN_LINK
  2 | #define BOOST_TEST_MODULE HomomorphicOperationsModule
  3 | #include <cstddef>
  4 | #include <boost/test/unit_test.hpp>
  5 | 
  6 | #include "she.hpp"
  7 | #include "serialization_formats.hpp"
  8 | 
  9 | using std::vector;
 10 | 
 11 | using she::PrivateKey;
 12 | using she::ParameterSet;
 13 | using she::CompressedCiphertext;
 14 | using she::PlaintextArray;
 15 | using she::EncryptedArray;
 16 | 
 17 | using she::sum;
 18 | using she::product;
 19 | 
 20 | 
 21 | BOOST_AUTO_TEST_SUITE(HomomorphicOperationsSuite)
 22 | 
 23 | BOOST_AUTO_TEST_CASE(bitwise_xor)
 24 | {
 25 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
 26 | 
 27 |     struct Input {
 28 |         vector<bool> p1;
 29 |         vector<bool> p2;
 30 |         vector<bool> p1_xor_p2;
 31 |     };
 32 | 
 33 |     const auto inputs = {
 34 |         Input{
 35 |             {1, 0, 1, 0, 1, 1, 1, 1},
 36 |             {1, 0, 1, 0, 1, 1, 1, 1},
 37 |             {0, 0, 0, 0, 0, 0, 0, 0}
 38 |         },
 39 | 
 40 |         Input{
 41 |             {1, 0, 1, 0, 1, 0, 1, 0},
 42 |             {1, 0, 1, 0, 1, 1, 1, 1},
 43 |             {0, 0, 0, 0, 0, 1, 0, 1}
 44 |         },
 45 | 
 46 |         Input{
 47 |             {1, 0, 1, 0, 1, 1, 1, 1},
 48 |             {0, 1, 0, 1, 0, 0, 0, 0},
 49 |             {1, 1, 1, 1, 1, 1, 1, 1}
 50 |         },
 51 |     };
 52 | 
 53 |     for (const auto & input : inputs) {
 54 | 
 55 |         {
 56 |             const auto c1 = sk.encrypt(input.p1).expand();
 57 |             const auto c2 = sk.encrypt(input.p2).expand();
 58 | 
 59 |             const auto c1_xor_c2 = c1 ^ c2;
 60 | 
 61 |             BOOST_CHECK_EQUAL(c1_xor_c2.degree(), 1);
 62 |             BOOST_CHECK(sk.decrypt(c1_xor_c2) == input.p1_xor_p2);
 63 |         }
 64 | 
 65 |         {
 66 |             const auto c1 = sk.encrypt(input.p1).expand();
 67 | 
 68 |             const auto c1_xor_p2 = c1 ^ PlaintextArray(input.p2);
 69 | 
 70 |             BOOST_CHECK_EQUAL(c1_xor_p2.degree(), 1);
 71 |             BOOST_CHECK(sk.decrypt(c1_xor_p2) == input.p1_xor_p2);
 72 |         }
 73 | 
 74 |         {
 75 |             const auto c1 = sk.encrypt(input.p1).expand();
 76 | 
 77 |             const auto c1_xor_p2 = PlaintextArray(input.p2) ^ c1;
 78 | 
 79 |             BOOST_CHECK_EQUAL(c1_xor_p2.degree(), 1);
 80 |             BOOST_CHECK(sk.decrypt(c1_xor_p2) == input.p1_xor_p2);
 81 |         }
 82 | 
 83 |         {
 84 |             const auto c2 = sk.encrypt(input.p2).expand();
 85 | 
 86 |             const auto c2_xor_p1 = c2 ^ PlaintextArray(input.p1);
 87 | 
 88 |             BOOST_CHECK_EQUAL(c2_xor_p1.degree(), 1);
 89 |             BOOST_CHECK(sk.decrypt(c2_xor_p1) == input.p1_xor_p2);
 90 |         }
 91 | 
 92 |         {
 93 |             const auto c2 = sk.encrypt(input.p2).expand();
 94 | 
 95 |             const auto c2_xor_p1 = PlaintextArray(input.p1) ^ c2;
 96 | 
 97 |             BOOST_CHECK_EQUAL(c2_xor_p1.degree(), 1);
 98 |             BOOST_CHECK(sk.decrypt(c2_xor_p1) == input.p1_xor_p2);
 99 |         }
100 | 
101 |         {
102 |             const auto p1_xor_p2 = PlaintextArray(input.p1) ^ PlaintextArray(input.p2);
103 |             BOOST_CHECK(p1_xor_p2.elements() == input.p1_xor_p2);
104 |         }
105 |     }
106 | }
107 | 
108 | BOOST_AUTO_TEST_CASE(multiple_arrays_sum)
109 | {
110 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
111 | 
112 |     vector<vector<bool> > inputs = {
113 |         {1, 1, 1, 1, 0, 0, 1, 1},
114 |         {0, 0, 0, 1, 0, 1, 0, 1},
115 |         {},
116 |         {1, 1, 1, 1, 0, 0},
117 |         {1, 1, 0, 0, 0, 1, 0, 1},
118 |         {1, 0, 0, 0, 0, 1, 1, 0},
119 |     };
120 | 
121 |     vector<bool> expected_result =
122 |         {0, 1, 0, 1, 0, 1, 0, 1};
123 | 
124 |     {
125 |         vector<EncryptedArray> encrypted_inputs;
126 |         for (const auto & input : inputs) {
127 |             encrypted_inputs.push_back(sk.encrypt(input).expand());
128 |         }
129 | 
130 |         const auto result = sum(encrypted_inputs);
131 |         const auto decrypted_result = sk.decrypt(result);
132 | 
133 |         BOOST_CHECK_EQUAL(result.degree(), 1);
134 |         BOOST_CHECK(decrypted_result == expected_result);
135 |     }
136 | 
137 |     {
138 |         vector<PlaintextArray> plaintext_inputs;
139 |         for (const auto & input : inputs) {
140 |             plaintext_inputs.push_back(PlaintextArray(input));
141 |         }
142 | 
143 |         const auto result = sum(plaintext_inputs);
144 |         BOOST_CHECK(result.elements() == expected_result);
145 |     }
146 | }
147 | 
148 | BOOST_AUTO_TEST_CASE(bitwise_and)
149 | {
150 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
151 | 
152 |     struct Input {
153 |         vector<bool> p1;
154 |         vector<bool> p2;
155 |         vector<bool> p1_and_p2;
156 |     };
157 | 
158 |     const auto inputs = {
159 |         Input{
160 |             {1, 0, 1, 0, 1, 1, 1, 1},
161 |             {1, 0, 1, 0, 1, 1, 1, 1},
162 |             {1, 0, 1, 0, 1, 1, 1, 1}
163 |         },
164 | 
165 |         Input{
166 |             {1, 0, 1, 0, 1, 0, 1, 0},
167 |             {1, 0, 1, 0, 1, 1, 1, 1},
168 |             {1, 0, 1, 0, 1, 0, 1, 0}
169 |         },
170 | 
171 |         Input{
172 |             {1, 0, 1, 0, 1, 1, 1, 1},
173 |             {0, 1, 0, 1, 0, 0, 0, 0},
174 |             {0, 0, 0, 0, 0, 0, 0, 0}
175 |         },
176 |     };
177 | 
178 |     for (const auto & input : inputs) {
179 | 
180 |         {
181 |             const auto c1 = sk.encrypt(input.p1).expand();
182 |             const auto c2 = sk.encrypt(input.p2).expand();
183 | 
184 |             const auto c1_and_c2 = c1 & c2;
185 | 
186 |             BOOST_CHECK_EQUAL(c1_and_c2.degree(), 2);
187 |             BOOST_CHECK(sk.decrypt(c1_and_c2) == input.p1_and_p2);
188 |         }
189 | 
190 |         {
191 |             const auto c1 = sk.encrypt(input.p1).expand();
192 | 
193 |             const auto c1_and_p2 = c1 & PlaintextArray(input.p2);
194 | 
195 |             BOOST_CHECK_EQUAL(c1_and_p2.degree(), 1);
196 |             BOOST_CHECK(sk.decrypt(c1_and_p2) == input.p1_and_p2);
197 |         }
198 | 
199 |         {
200 |             const auto c1 = sk.encrypt(input.p1).expand();
201 | 
202 |             const auto c1_and_p2 = PlaintextArray(input.p2) & c1;
203 | 
204 |             BOOST_CHECK_EQUAL(c1_and_p2.degree(), 1);
205 |             BOOST_CHECK(sk.decrypt(c1_and_p2) == input.p1_and_p2);
206 |         }
207 | 
208 |         {
209 |             const auto c2 = sk.encrypt(input.p2).expand();
210 | 
211 |             const auto c2_and_p1 = c2 & PlaintextArray(input.p1);
212 | 
213 |             BOOST_CHECK_EQUAL(c2_and_p1.degree(), 1);
214 |             BOOST_CHECK(sk.decrypt(c2_and_p1) == input.p1_and_p2);
215 |         }
216 | 
217 |         {
218 |             const auto c2 = sk.encrypt(input.p2).expand();
219 | 
220 |             const auto c2_and_p1 = PlaintextArray(input.p1) & c2;
221 | 
222 |             BOOST_CHECK_EQUAL(c2_and_p1.degree(), 1);
223 |             BOOST_CHECK(sk.decrypt(c2_and_p1) == input.p1_and_p2);
224 |         }
225 | 
226 |         {
227 |             const auto p1_and_p2 = PlaintextArray(input.p1) & PlaintextArray(input.p2);
228 | 
229 |             BOOST_CHECK(p1_and_p2.elements() == input.p1_and_p2);
230 |         }
231 |     }
232 | }
233 | 
234 | BOOST_AUTO_TEST_CASE(multiple_arrays_product)
235 | {
236 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 5, 42));
237 | 
238 |     vector<vector<bool> > inputs = {
239 |         {1, 1, 1, 1, 0, 0, 1, 1},
240 |         {0, 0, 0, 1, 0, 1},
241 |         {1, 1, 1, 1, 0, 0, 0, 1},
242 |         {},
243 |         {1, 1, 0, 1, 0, 1, 0, 1},
244 |         {1, 0, 0, 1, 0, 1, 1, 1},
245 |     };
246 | 
247 |     vector<bool> expected_result =
248 |         {0, 0, 0, 1, 0, 0, 0, 1};
249 | 
250 |     {
251 |         vector<EncryptedArray> encrypted_inputs;
252 |         for (const auto & input : inputs) {
253 |             encrypted_inputs.push_back(sk.encrypt(input).expand());
254 |         }
255 | 
256 |         const auto result = product(encrypted_inputs);
257 |         const auto decrypted_result = sk.decrypt(result);
258 | 
259 |         BOOST_CHECK_EQUAL(result.degree(), inputs.size());
260 |         BOOST_CHECK(decrypted_result == expected_result);
261 |     }
262 | 
263 |     {
264 |         vector<PlaintextArray> plaintext_inputs;
265 |         for (const auto & input : inputs) {
266 |             plaintext_inputs.push_back(PlaintextArray(input));
267 |         }
268 | 
269 |         const auto result = product(plaintext_inputs);
270 |         BOOST_CHECK(result.elements() == expected_result);
271 |     }
272 | }
273 | 
274 | BOOST_AUTO_TEST_CASE(array_select)
275 | {
276 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 4, 42));
277 |     const vector<vector<bool> > raw_plaintext_arrays = {
278 |         {1, 1, 1, 1},
279 |         {0, 1, 0, 1},
280 |         {1, 0, 1, 0},
281 |         {0, 0, 0, 0},
282 |     };
283 | 
284 |     vector<PlaintextArray> plaintext_arrays;
285 |     for (const auto & raw_plaintext_array : raw_plaintext_arrays) {
286 |         plaintext_arrays.push_back(PlaintextArray(raw_plaintext_array));
287 |     }
288 | 
289 |     vector<EncryptedArray> encrypted_arrays;
290 |     for (const auto & raw_plaintext_array : raw_plaintext_arrays) {
291 |         encrypted_arrays.push_back(sk.encrypt(raw_plaintext_array).expand());
292 |     }
293 | 
294 |     vector<vector<bool> > raw_plaintext_selections = {
295 |         {1, 0, 0, 0},
296 |         {0, 1, 0, 0},
297 |         {0, 0, 1, 0},
298 |         {0, 0, 0, 1},
299 |     };
300 | 
301 |     vector<EncryptedArray> encrypted_selections;
302 |     for (const auto & raw_plaintext_selection : raw_plaintext_selections) {
303 |         encrypted_selections.push_back(sk.encrypt(raw_plaintext_selection).expand());
304 |     }
305 | 
306 |     vector<PlaintextArray> plaintext_selections;
307 |     for (const auto & raw_plaintext_selection : raw_plaintext_selections) {
308 |         plaintext_selections.push_back(PlaintextArray(raw_plaintext_selection));
309 |     }
310 | 
311 |     {
312 |         for (size_t i = 0; i < encrypted_selections.size(); ++i) {
313 |             const auto result = encrypted_selections[i].select(encrypted_arrays);
314 |             const vector<bool> decrypted_result = sk.decrypt(result);
315 | 
316 |             BOOST_CHECK_EQUAL(result.degree(), 2);
317 |             BOOST_CHECK(decrypted_result == plaintext_arrays[i].elements());
318 |         }
319 |     }
320 | 
321 |     {
322 |         for (size_t i = 0; i < encrypted_selections.size(); ++i) {
323 |             const auto result = encrypted_selections[i].select(plaintext_arrays);
324 |             const vector<bool> decrypted_result = sk.decrypt(result);
325 | 
326 |             BOOST_CHECK_EQUAL(result.degree(), 1);
327 |             BOOST_CHECK(decrypted_result == plaintext_arrays[i].elements());
328 |         }
329 |     }
330 | 
331 |     {
332 |         for (size_t i = 0; i < plaintext_selections.size(); ++i) {
333 |             const auto result = plaintext_selections[i].select(encrypted_arrays);
334 |             const vector<bool> decrypted_result = sk.decrypt(result);
335 | 
336 |             BOOST_CHECK_EQUAL(result.degree(), 1);
337 |             BOOST_CHECK(decrypted_result == plaintext_arrays[i].elements());
338 |         }
339 |     }
340 | 
341 |     {
342 |         for (size_t i = 0; i < plaintext_selections.size(); ++i) {
343 |             const auto result = plaintext_selections[i].select(plaintext_arrays);
344 |             BOOST_CHECK(result.elements() == plaintext_arrays[i].elements());
345 |         }
346 |     }
347 | }
348 | 
349 | BOOST_AUTO_TEST_CASE(array_equal)
350 | {
351 |     const PrivateKey sk(ParameterSet::generate_parameter_set(22, 4, 42));
352 |     const vector<vector<bool> > raw_plaintext_arrays = {
353 |         vector<bool>{1, 1, 1, 1},
354 |         vector<bool>{0, 1, 0, 1},
355 |         vector<bool>{1, 0, 1, 0},
356 |         vector<bool>{0, 1, 0, 1},
357 |     };
358 | 
359 |     vector<PlaintextArray> plaintext_arrays;
360 |     for (const auto & raw_plaintext_array : raw_plaintext_arrays) {
361 |         plaintext_arrays.push_back(PlaintextArray(raw_plaintext_array));
362 |     }
363 | 
364 |     vector<EncryptedArray> encrypted_arrays;
365 |     for (const auto & raw_plaintext_array : raw_plaintext_arrays) {
366 |         encrypted_arrays.push_back(sk.encrypt(raw_plaintext_array).expand());
367 |     }
368 | 
369 |     const vector<vector<bool> > raw_plaintext_inputs = {
370 |         vector<bool>{1, 1, 0, 0},
371 |         vector<bool>{1, 1, 1, 1},
372 |         vector<bool>{0, 1, 0, 1},
373 |         vector<bool>{1, 0, 1, 0},
374 |     };
375 | 
376 |     vector<PlaintextArray> plaintext_inputs;
377 |     for (const auto & raw_plaintext_input : raw_plaintext_inputs) {
378 |         plaintext_inputs.push_back(PlaintextArray(raw_plaintext_input));
379 |     }
380 | 
381 |     vector<EncryptedArray> encrypted_inputs;
382 |     for (const auto & raw_plaintext_input : raw_plaintext_inputs) {
383 |         encrypted_inputs.push_back(sk.encrypt(raw_plaintext_input).expand());
384 |     }
385 | 
386 |     const vector<vector<bool> > expected_results = {
387 |         {0, 0, 0, 0},
388 |         {1, 0, 0, 0},
389 |         {0, 1, 0, 1},
390 |         {0, 0, 1, 0}
391 |     };
392 | 
393 |     {
394 |         for (size_t i = 0; i < encrypted_inputs.size(); ++i) {
395 |             const auto result = encrypted_inputs[i].equal(encrypted_arrays);
396 |             const vector<bool> decrypted_result = sk.decrypt(result);
397 | 
398 |             BOOST_CHECK_EQUAL(result.degree(), 4);
399 |             BOOST_CHECK(decrypted_result == expected_results[i]);
400 |         }
401 |     }
402 | 
403 |     {
404 | 
405 |         for (size_t i = 0; i < plaintext_inputs.size(); ++i) {
406 |             const auto result = plaintext_inputs[i].equal(encrypted_arrays);
407 |             const vector<bool> decrypted_result = sk.decrypt(result);
408 | 
409 |             BOOST_CHECK_EQUAL(result.degree(), 4);
410 |             BOOST_CHECK(decrypted_result == expected_results[i]);
411 |         }
412 |     }
413 | 
414 |     {
415 |         for (size_t i = 0; i < encrypted_inputs.size(); ++i) {
416 |             const auto result = encrypted_inputs[i].equal(plaintext_arrays);
417 |             const vector<bool> decrypted_result = sk.decrypt(result);
418 | 
419 |             BOOST_CHECK_EQUAL(result.degree(), 1);
420 |             BOOST_CHECK(decrypted_result == expected_results[i]);
421 |         }
422 |     }
423 | 
424 |     {
425 |         for (size_t i = 0; i < plaintext_inputs.size(); ++i) {
426 |             const auto result = plaintext_inputs[i].equal(plaintext_arrays);
427 |             BOOST_CHECK(result.elements() == expected_results[i]);
428 |         }
429 |     }
430 | }
431 | 
432 | BOOST_AUTO_TEST_SUITE_END()
433 | 


--------------------------------------------------------------------------------
/src/ciphertext.cpp:
--------------------------------------------------------------------------------
  1 | #include <cmath>
  2 | 
  3 | #include "she.hpp"
  4 | #include "she/exceptions.hpp"
  5 | 
  6 | using std::min;
  7 | using std::max;
  8 | using std::set;
  9 | using std::vector;
 10 | 
 11 | 
 12 | namespace she
 13 | {
 14 | 
 15 | std::set<mpz_class> EncryptedArray::public_elements = {};
 16 | 
 17 | EncryptedArray::EncryptedArray(const mpz_class & x, unsigned int max_degree, unsigned int degree) noexcept :
 18 |   _degree(degree),
 19 |   _max_degree(max_degree)
 20 | {
 21 |     // ASSERT(degree >= 1, "Degree must be at least 1");
 22 | 
 23 |     set_public_element(x);
 24 | }
 25 | 
 26 | bool EncryptedArray::operator==(const EncryptedArray & other) const noexcept
 27 | {
 28 |     return (_elements == other._elements)
 29 |         && (*_public_element_ptr == *other._public_element_ptr);
 30 | }
 31 | 
 32 | void EncryptedArray::set_public_element(const mpz_class & x) noexcept
 33 | {
 34 |     auto result = public_elements.emplace(x);
 35 |     _public_element_ptr = result.first;
 36 |     _initialized = true;
 37 | }
 38 | 
 39 | EncryptedArray &
 40 | EncryptedArray::operator^=(const PlaintextArray & other) noexcept
 41 | {
 42 |     ASSERT(_initialized, "EncryptedArray must be initialized");
 43 | 
 44 |     const auto & public_element = *_public_element_ptr;
 45 | 
 46 |     const size_t n = min(_elements.size(), other._elements.size());
 47 | 
 48 |     // Do natural arithmetic operation modulo public element
 49 |     for (size_t i = 0; i < n; ++i) {
 50 |         _elements[i] += other._elements[i];
 51 |         _elements[i] %= public_element;
 52 |     }
 53 | 
 54 |     // If sizes don't match pad with zeros from the right
 55 |     for (size_t i = n; i < other._elements.size(); ++i) {
 56 |         _elements.push_back(other._elements[i]);
 57 |     }
 58 | 
 59 |     return *this;
 60 | }
 61 | 
 62 | EncryptedArray &
 63 | EncryptedArray::operator^=(const EncryptedArray & other) noexcept
 64 | {
 65 |     ASSERT(_initialized, "EncryptedArray must be initialized");
 66 | 
 67 |     const auto & public_element = *_public_element_ptr;
 68 | 
 69 |     _degree = max(_degree, other._degree);
 70 | 
 71 |     const size_t n = min(_elements.size(), other._elements.size());
 72 | 
 73 |     // Do natural arithmetic operation modulo public element
 74 |     for (size_t i = 0; i < n; ++i) {
 75 |         _elements[i] += other._elements[i];
 76 |         _elements[i] %= public_element;
 77 |     }
 78 | 
 79 |     // If sizes don't match pad with zeros from the right
 80 |     for (size_t i = n; i < other._elements.size(); ++i) {
 81 |         _elements.push_back(other._elements[i]);
 82 |     }
 83 | 
 84 |     return *this;
 85 | }
 86 | 
 87 | EncryptedArray &
 88 | EncryptedArray::operator&=(const PlaintextArray & other) noexcept
 89 | {
 90 |     ASSERT(_initialized, "EncryptedArray must be initialized");
 91 | 
 92 |     const auto & public_element = *_public_element_ptr;
 93 | 
 94 |     const size_t n = min(_elements.size(), other._elements.size());
 95 | 
 96 |     // Do natural arithmetic operation modulo public element
 97 |     for (size_t i = 0; i < n; ++i) {
 98 |         _elements[i] *= other._elements[i];
 99 |         _elements[i] %= public_element;
100 |     }
101 | 
102 |     // If sizes don't match pad with ones from the right
103 |     for (size_t i = n; i < other._elements.size(); ++i) {
104 |         _elements.push_back(other._elements[i]);
105 |     }
106 | 
107 |     return *this;
108 | }
109 | 
110 | EncryptedArray &
111 | EncryptedArray::operator&=(const EncryptedArray & other) noexcept
112 | {
113 |     ASSERT(_initialized, "EncryptedArray must be initialized");
114 | 
115 |     const auto & public_element = *_public_element_ptr;
116 | 
117 |     _degree = _degree + other._degree;
118 | 
119 |     const size_t n = min(_elements.size(), other._elements.size());
120 | 
121 |     // Do natural arithmetic operation modulo public element
122 |     for (size_t i = 0; i < n; ++i) {
123 |         _elements[i] *= other._elements[i];
124 |         _elements[i] %= public_element;
125 |     }
126 | 
127 |     // If sizes don't match pad with ones from the right
128 |     for (size_t i = n; i < other._elements.size(); ++i) {
129 |         _elements.push_back(other._elements[i]);
130 |     }
131 | 
132 |     return *this;
133 | }
134 | 
135 | 
136 | const PlaintextArray
137 | PlaintextArray::equal(const std::vector<PlaintextArray> & arrays) const noexcept
138 | {
139 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
140 | 
141 |     PlaintextArray result {};
142 | 
143 |     for (const auto & array : arrays) {
144 | 
145 |         // Find difference (xor) between this and array
146 |         const auto difference = *this ^ array;
147 | 
148 |         // Multiply (and) all elements of the difference array + 1
149 |         // The result will decrypt to 1 iff all elements of this and array are equal
150 |         bool all = 1;
151 |         for (const auto & element : difference._elements)
152 |         {
153 |             all &= (element ^ 1);
154 |         }
155 | 
156 |         result._elements.push_back(all);
157 |     }
158 | 
159 |     return result;
160 | }
161 | 
162 | const EncryptedArray
163 | PlaintextArray::equal(const std::vector<EncryptedArray> & arrays) const noexcept
164 | {
165 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
166 | 
167 |     const auto & public_element = arrays.front().public_element();
168 | 
169 |     EncryptedArray result( arrays.front().public_element()
170 |                          , arrays.front().max_degree()
171 |                          , arrays.front().degree()
172 |                          );
173 | 
174 |     for (const auto & array : arrays) {
175 | 
176 |         // Find difference (xor) between this and array
177 |         const auto difference = array ^ *this;
178 | 
179 |         // Multiply (and) all elements of the difference array + 1
180 |         // The result will decrypt to 1 iff all elements of this and array are equal
181 |         mpz_class all = 1;
182 |         for (const auto & element : difference._elements)
183 |         {
184 |             all *= (element + 1);
185 |             all %= public_element;
186 |         }
187 | 
188 |         result._elements.push_back(all);
189 | 
190 |         // Set result degree to maximum degree of arrays
191 |         auto current_degree = difference._degree * difference._elements.size();
192 |         if (current_degree > result._degree) {
193 |             result._degree = current_degree;
194 |         }
195 |     }
196 | 
197 |     return result;
198 | }
199 | 
200 | const EncryptedArray
201 | EncryptedArray::equal(const std::vector<PlaintextArray> & arrays) const noexcept
202 | {
203 |     ASSERT(_initialized, "EncryptedArray must be initialized");
204 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
205 | 
206 |     const auto & public_element = *_public_element_ptr;
207 | 
208 |     EncryptedArray result(public_element, _max_degree, _degree);
209 | 
210 |     for (const auto & array : arrays) {
211 | 
212 |         // Find difference (xor) between this and array
213 |         const auto difference = *this ^ array;
214 | 
215 |         // Multiply (and) all elements of the difference array + 1
216 |         // The result will decrypt to 1 iff all elements of this and array are equal
217 |         mpz_class all = 1;
218 |         for (const auto & element : difference._elements)
219 |         {
220 |             all *= (element + 1);
221 |             all %= public_element;
222 |         }
223 | 
224 |         result._elements.push_back(all);
225 |     }
226 | 
227 |     return result;
228 | }
229 | 
230 | 
231 | const EncryptedArray
232 | EncryptedArray::equal(const std::vector<EncryptedArray> & arrays) const noexcept
233 | {
234 |     ASSERT(_initialized, "EncryptedArray must be initialized");
235 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
236 | 
237 |     const auto & public_element = *_public_element_ptr;
238 | 
239 |     EncryptedArray result(public_element, _max_degree);
240 | 
241 |     for (const auto & array : arrays) {
242 | 
243 |         // Find difference (xor) between this and array
244 |         const auto difference = *this ^ array;
245 | 
246 |         // Multiply (and) all elements of the difference array + 1
247 |         // The result will decrypt to 1 iff all elements of this and array are equal
248 |         mpz_class all = 1;
249 |         for (const auto & element : difference._elements)
250 |         {
251 |             all *= (element + 1);
252 |             all %= public_element;
253 |         }
254 | 
255 |         result._elements.push_back(all);
256 | 
257 |         // Set result degree to maximum degree of arrays
258 |         auto current_degree = difference._degree * difference._elements.size();
259 |         if (current_degree > result._degree) {
260 |             result._degree = current_degree;
261 |         }
262 |     }
263 | 
264 |     return result;
265 | }
266 | 
267 | const PlaintextArray
268 | PlaintextArray::select(const std::vector<PlaintextArray> & arrays) const noexcept
269 | {
270 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
271 | 
272 |     PlaintextArray result {};
273 | 
274 |     for (size_t i = 0; i < min(_elements.size(), arrays.size()); ++i) {
275 | 
276 |         PlaintextArray selected {};
277 | 
278 |         // Multiply i-th element of this by all of the elements in array
279 |         // The result will be decrypted to either original array or to array of zeros
280 |         for (const auto & selected_element : arrays[i]._elements) {
281 |             selected._elements.push_back(selected_element & _elements[i]);
282 |         }
283 | 
284 |         result ^= selected;
285 |     }
286 | 
287 |     return result;
288 | }
289 | 
290 | const EncryptedArray
291 | PlaintextArray::select(const std::vector<EncryptedArray> & arrays) const noexcept
292 | {
293 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
294 | 
295 |     const auto & public_element = arrays.front().public_element();
296 | 
297 |     EncryptedArray result( arrays.front().public_element()
298 |                          , arrays.front().max_degree()
299 |                          , arrays.front().degree()
300 |                          );
301 | 
302 |     for (size_t i = 0; i < min(_elements.size(), arrays.size()); ++i) {
303 | 
304 |         EncryptedArray selected(public_element, result._max_degree, arrays[i]._degree);
305 | 
306 |         // Multiply i-th element of this by all of the elements in array
307 |         // The result will be decrypted to either original array or to array of zeros
308 |         for (const auto & selected_element : arrays[i]._elements) {
309 |             selected._elements.push_back((selected_element * _elements[i]) % public_element);
310 |         }
311 | 
312 |         result ^= selected;
313 |     }
314 | 
315 |     return result;
316 | }
317 | 
318 | const EncryptedArray
319 | EncryptedArray::select(const std::vector<PlaintextArray> & arrays) const noexcept
320 | {
321 |     ASSERT(_initialized, "EncryptedArray must be initialized");
322 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
323 | 
324 |     const auto & public_element = *_public_element_ptr;
325 | 
326 |     EncryptedArray result(public_element, _max_degree, _degree);
327 | 
328 |     for (size_t i = 0; i < min(_elements.size(), arrays.size()); ++i) {
329 | 
330 |         EncryptedArray selected(public_element, _max_degree, _degree);
331 | 
332 |         // Multiply i-th element of this by all of the elements in array
333 |         // The result will be decrypted to either original array or to array of zeros
334 |         for (const auto & selected_element : arrays[i]._elements) {
335 |             selected._elements.push_back(selected_element * _elements[i]);
336 |         }
337 | 
338 |         result ^= selected;
339 |     }
340 | 
341 |     return result;
342 | }
343 | 
344 | const EncryptedArray
345 | EncryptedArray::select(const std::vector<EncryptedArray> & arrays) const noexcept
346 | {
347 |     ASSERT(_initialized, "EncryptedArray must be initialized");
348 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
349 | 
350 |     const auto & public_element = *_public_element_ptr;
351 | 
352 |     EncryptedArray result(public_element, _max_degree);
353 | 
354 |     for (size_t i = 0; i < min(_elements.size(), arrays.size()); ++i) {
355 | 
356 |         EncryptedArray selected(public_element, _max_degree);
357 | 
358 |         // Multiply i-th element of this by all of the elements in array
359 |         // The result will be decrypted to either original array or to array of zeros
360 |         for (const auto & selected_element : arrays[i]._elements) {
361 |             selected._elements.push_back((selected_element * _elements[i]) % public_element);
362 |         }
363 | 
364 |         selected._degree =  _degree + arrays[i]._degree;
365 | 
366 |         result ^= selected;
367 |     }
368 | 
369 |     return result;
370 | }
371 | 
372 | EncryptedArray &
373 | EncryptedArray::extend(const EncryptedArray & other) noexcept
374 | {
375 |     ASSERT(_initialized, "EncryptedArray must be initialized");
376 | 
377 |     for (const auto & element : other._elements) {
378 |         _elements.push_back(element);
379 |     }
380 | 
381 |     _degree = max(_degree, other._degree);
382 | 
383 |     return *this;
384 | }
385 | 
386 | const mpz_class &
387 | EncryptedArray::public_element() const noexcept
388 | {
389 |     ASSERT(_initialized, "EncryptedArray must be initialized");
390 | 
391 |     return *_public_element_ptr;
392 | }
393 | 
394 | PlaintextArray
395 | sum(const vector<PlaintextArray> & arrays) noexcept
396 | {
397 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
398 | 
399 |     PlaintextArray result {};
400 | 
401 |     for (const auto & array : arrays) {
402 |         result ^= array;
403 |     }
404 | 
405 |     return result;
406 | }
407 | 
408 | EncryptedArray
409 | sum(const vector<EncryptedArray> & arrays) noexcept
410 | {
411 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
412 | 
413 |     EncryptedArray result( arrays.front().public_element()
414 |                          , arrays.front().max_degree()
415 |                          , arrays.front().degree()
416 |                          );
417 | 
418 |     for (const auto & array : arrays) {
419 |         result ^= array;
420 |     }
421 | 
422 |     return result;
423 | }
424 | 
425 | PlaintextArray
426 | product(const vector<PlaintextArray> & arrays) noexcept
427 | {
428 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
429 | 
430 |     PlaintextArray result {};
431 | 
432 |     for (const auto & array : arrays) {
433 |         result &= array;
434 |     }
435 | 
436 |     return result;
437 | }
438 | 
439 | EncryptedArray
440 | product(const vector<EncryptedArray> & arrays) noexcept
441 | {
442 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
443 | 
444 |     EncryptedArray result( arrays.front().public_element()
445 |                          , arrays.front().max_degree()
446 |                          , 0);
447 | 
448 |     for (const auto & array : arrays) {
449 |         result &= array;
450 |     }
451 | 
452 |     return result;
453 | }
454 | 
455 | PlaintextArray
456 | concat(const vector<PlaintextArray> & arrays) noexcept
457 | {
458 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
459 | 
460 |     PlaintextArray result {};
461 | 
462 |     for (const auto & array : arrays) {
463 |         result.extend(array);
464 |     }
465 | 
466 |     return result;
467 | }
468 | 
469 | EncryptedArray
470 | concat(const vector<EncryptedArray> & arrays) noexcept
471 | {
472 |     ASSERT(arrays.size() > 0, "Input array must not be empty");
473 | 
474 |     EncryptedArray result( arrays.front().public_element()
475 |                          , arrays.front().max_degree()
476 |                          , arrays.front().degree()
477 |                          );
478 | 
479 |     for (const auto & array : arrays) {
480 |         result.extend(array);
481 |     }
482 | 
483 |     return result;
484 | }
485 | 
486 | CompressedCiphertext::CompressedCiphertext(const ParameterSet & params) noexcept :
487 |   _parameter_set(params)
488 | {
489 |     initialize_prf_stream();
490 | }
491 | 
492 | void CompressedCiphertext::initialize_prf_stream() const noexcept
493 | {
494 |     _prf_stream.reset(
495 |         new PseudoRandomStream{_parameter_set.ciphertext_size_bits, _parameter_set.prf_seed});
496 | }
497 | 
498 | bool CompressedCiphertext::operator==(const CompressedCiphertext & other) const noexcept
499 | {
500 |     return (_parameter_set == other._parameter_set)
501 |         && (_public_element_delta == other._public_element_delta)
502 |         && (_elements_deltas == other._elements_deltas);
503 | }
504 | 
505 | EncryptedArray CompressedCiphertext::expand() const noexcept
506 | {
507 |     _prf_stream->reset();
508 | 
509 |     // Restore public element
510 |     const auto & prf_output = _prf_stream->next();
511 |     const auto public_element = prf_output - _public_element_delta;
512 | 
513 |     EncryptedArray result(public_element, _parameter_set.degree());
514 | 
515 |     // Restore ciphertext elements
516 |     for (const auto & delta : _elements_deltas) {
517 |         const auto & prf_output = _prf_stream->next();
518 |         result._elements.push_back(prf_output - delta);
519 |     }
520 | 
521 |     return result;
522 | }
523 | 
524 | } // namespace she
525 | 


--------------------------------------------------------------------------------
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--------------------------------------------------------------------------------
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  2 |                        Version 3, 29 June 2007
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170 | not control copyright.  Those thus making or running the covered works
171 | for you must do so exclusively on your behalf, under your direction
172 | and control, on terms that prohibit them from making any copies of
173 | your copyrighted material outside their relationship with you.
174 | 
175 |   Conveying under any other circumstances is permitted solely under
176 | the conditions stated below.  Sublicensing is not allowed; section 10
177 | makes it unnecessary.
178 | 
179 |   3. Protecting Users' Legal Rights From Anti-Circumvention Law.
180 | 
181 |   No covered work shall be deemed part of an effective technological
182 | measure under any applicable law fulfilling obligations under article
183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or
184 | similar laws prohibiting or restricting circumvention of such
185 | measures.
186 | 
187 |   When you convey a covered work, you waive any legal power to forbid
188 | circumvention of technological measures to the extent such circumvention
189 | is effected by exercising rights under this License with respect to
190 | the covered work, and you disclaim any intention to limit operation or
191 | modification of the work as a means of enforcing, against the work's
192 | users, your or third parties' legal rights to forbid circumvention of
193 | technological measures.
194 | 
195 |   4. Conveying Verbatim Copies.
196 | 
197 |   You may convey verbatim copies of the Program's source code as you
198 | receive it, in any medium, provided that you conspicuously and
199 | appropriately publish on each copy an appropriate copyright notice;
200 | keep intact all notices stating that this License and any
201 | non-permissive terms added in accord with section 7 apply to the code;
202 | keep intact all notices of the absence of any warranty; and give all
203 | recipients a copy of this License along with the Program.
204 | 
205 |   You may charge any price or no price for each copy that you convey,
206 | and you may offer support or warranty protection for a fee.
207 | 
208 |   5. Conveying Modified Source Versions.
209 | 
210 |   You may convey a work based on the Program, or the modifications to
211 | produce it from the Program, in the form of source code under the
212 | terms of section 4, provided that you also meet all of these conditions:
213 | 
214 |     a) The work must carry prominent notices stating that you modified
215 |     it, and giving a relevant date.
216 | 
217 |     b) The work must carry prominent notices stating that it is
218 |     released under this License and any conditions added under section
219 |     7.  This requirement modifies the requirement in section 4 to
220 |     "keep intact all notices".
221 | 
222 |     c) You must license the entire work, as a whole, under this
223 |     License to anyone who comes into possession of a copy.  This
224 |     License will therefore apply, along with any applicable section 7
225 |     additional terms, to the whole of the work, and all its parts,
226 |     regardless of how they are packaged.  This License gives no
227 |     permission to license the work in any other way, but it does not
228 |     invalidate such permission if you have separately received it.
229 | 
230 |     d) If the work has interactive user interfaces, each must display
231 |     Appropriate Legal Notices; however, if the Program has interactive
232 |     interfaces that do not display Appropriate Legal Notices, your
233 |     work need not make them do so.
234 | 
235 |   A compilation of a covered work with other separate and independent
236 | works, which are not by their nature extensions of the covered work,
237 | and which are not combined with it such as to form a larger program,
238 | in or on a volume of a storage or distribution medium, is called an
239 | "aggregate" if the compilation and its resulting copyright are not
240 | used to limit the access or legal rights of the compilation's users
241 | beyond what the individual works permit.  Inclusion of a covered work
242 | in an aggregate does not cause this License to apply to the other
243 | parts of the aggregate.
244 | 
245 |   6. Conveying Non-Source Forms.
246 | 
247 |   You may convey a covered work in object code form under the terms
248 | of sections 4 and 5, provided that you also convey the
249 | machine-readable Corresponding Source under the terms of this License,
250 | in one of these ways:
251 | 
252 |     a) Convey the object code in, or embodied in, a physical product
253 |     (including a physical distribution medium), accompanied by the
254 |     Corresponding Source fixed on a durable physical medium
255 |     customarily used for software interchange.
256 | 
257 |     b) Convey the object code in, or embodied in, a physical product
258 |     (including a physical distribution medium), accompanied by a
259 |     written offer, valid for at least three years and valid for as
260 |     long as you offer spare parts or customer support for that product
261 |     model, to give anyone who possesses the object code either (1) a
262 |     copy of the Corresponding Source for all the software in the
263 |     product that is covered by this License, on a durable physical
264 |     medium customarily used for software interchange, for a price no
265 |     more than your reasonable cost of physically performing this
266 |     conveying of source, or (2) access to copy the
267 |     Corresponding Source from a network server at no charge.
268 | 
269 |     c) Convey individual copies of the object code with a copy of the
270 |     written offer to provide the Corresponding Source.  This
271 |     alternative is allowed only occasionally and noncommercially, and
272 |     only if you received the object code with such an offer, in accord
273 |     with subsection 6b.
274 | 
275 |     d) Convey the object code by offering access from a designated
276 |     place (gratis or for a charge), and offer equivalent access to the
277 |     Corresponding Source in the same way through the same place at no
278 |     further charge.  You need not require recipients to copy the
279 |     Corresponding Source along with the object code.  If the place to
280 |     copy the object code is a network server, the Corresponding Source
281 |     may be on a different server (operated by you or a third party)
282 |     that supports equivalent copying facilities, provided you maintain
283 |     clear directions next to the object code saying where to find the
284 |     Corresponding Source.  Regardless of what server hosts the
285 |     Corresponding Source, you remain obligated to ensure that it is
286 |     available for as long as needed to satisfy these requirements.
287 | 
288 |     e) Convey the object code using peer-to-peer transmission, provided
289 |     you inform other peers where the object code and Corresponding
290 |     Source of the work are being offered to the general public at no
291 |     charge under subsection 6d.
292 | 
293 |   A separable portion of the object code, whose source code is excluded
294 | from the Corresponding Source as a System Library, need not be
295 | included in conveying the object code work.
296 | 
297 |   A "User Product" is either (1) a "consumer product", which means any
298 | tangible personal property which is normally used for personal, family,
299 | or household purposes, or (2) anything designed or sold for incorporation
300 | into a dwelling.  In determining whether a product is a consumer product,
301 | doubtful cases shall be resolved in favor of coverage.  For a particular
302 | product received by a particular user, "normally used" refers to a
303 | typical or common use of that class of product, regardless of the status
304 | of the particular user or of the way in which the particular user
305 | actually uses, or expects or is expected to use, the product.  A product
306 | is a consumer product regardless of whether the product has substantial
307 | commercial, industrial or non-consumer uses, unless such uses represent
308 | the only significant mode of use of the product.
309 | 
310 |   "Installation Information" for a User Product means any methods,
311 | procedures, authorization keys, or other information required to install
312 | and execute modified versions of a covered work in that User Product from
313 | a modified version of its Corresponding Source.  The information must
314 | suffice to ensure that the continued functioning of the modified object
315 | code is in no case prevented or interfered with solely because
316 | modification has been made.
317 | 
318 |   If you convey an object code work under this section in, or with, or
319 | specifically for use in, a User Product, and the conveying occurs as
320 | part of a transaction in which the right of possession and use of the
321 | User Product is transferred to the recipient in perpetuity or for a
322 | fixed term (regardless of how the transaction is characterized), the
323 | Corresponding Source conveyed under this section must be accompanied
324 | by the Installation Information.  But this requirement does not apply
325 | if neither you nor any third party retains the ability to install
326 | modified object code on the User Product (for example, the work has
327 | been installed in ROM).
328 | 
329 |   The requirement to provide Installation Information does not include a
330 | requirement to continue to provide support service, warranty, or updates
331 | for a work that has been modified or installed by the recipient, or for
332 | the User Product in which it has been modified or installed.  Access to a
333 | network may be denied when the modification itself materially and
334 | adversely affects the operation of the network or violates the rules and
335 | protocols for communication across the network.
336 | 
337 |   Corresponding Source conveyed, and Installation Information provided,
338 | in accord with this section must be in a format that is publicly
339 | documented (and with an implementation available to the public in
340 | source code form), and must require no special password or key for
341 | unpacking, reading or copying.
342 | 
343 |   7. Additional Terms.
344 | 
345 |   "Additional permissions" are terms that supplement the terms of this
346 | License by making exceptions from one or more of its conditions.
347 | Additional permissions that are applicable to the entire Program shall
348 | be treated as though they were included in this License, to the extent
349 | that they are valid under applicable law.  If additional permissions
350 | apply only to part of the Program, that part may be used separately
351 | under those permissions, but the entire Program remains governed by
352 | this License without regard to the additional permissions.
353 | 
354 |   When you convey a copy of a covered work, you may at your option
355 | remove any additional permissions from that copy, or from any part of
356 | it.  (Additional permissions may be written to require their own
357 | removal in certain cases when you modify the work.)  You may place
358 | additional permissions on material, added by you to a covered work,
359 | for which you have or can give appropriate copyright permission.
360 | 
361 |   Notwithstanding any other provision of this License, for material you
362 | add to a covered work, you may (if authorized by the copyright holders of
363 | that material) supplement the terms of this License with terms:
364 | 
365 |     a) Disclaiming warranty or limiting liability differently from the
366 |     terms of sections 15 and 16 of this License; or
367 | 
368 |     b) Requiring preservation of specified reasonable legal notices or
369 |     author attributions in that material or in the Appropriate Legal
370 |     Notices displayed by works containing it; or
371 | 
372 |     c) Prohibiting misrepresentation of the origin of that material, or
373 |     requiring that modified versions of such material be marked in
374 |     reasonable ways as different from the original version; or
375 | 
376 |     d) Limiting the use for publicity purposes of names of licensors or
377 |     authors of the material; or
378 | 
379 |     e) Declining to grant rights under trademark law for use of some
380 |     trade names, trademarks, or service marks; or
381 | 
382 |     f) Requiring indemnification of licensors and authors of that
383 |     material by anyone who conveys the material (or modified versions of
384 |     it) with contractual assumptions of liability to the recipient, for
385 |     any liability that these contractual assumptions directly impose on
386 |     those licensors and authors.
387 | 
388 |   All other non-permissive additional terms are considered "further
389 | restrictions" within the meaning of section 10.  If the Program as you
390 | received it, or any part of it, contains a notice stating that it is
391 | governed by this License along with a term that is a further
392 | restriction, you may remove that term.  If a license document contains
393 | a further restriction but permits relicensing or conveying under this
394 | License, you may add to a covered work material governed by the terms
395 | of that license document, provided that the further restriction does
396 | not survive such relicensing or conveying.
397 | 
398 |   If you add terms to a covered work in accord with this section, you
399 | must place, in the relevant source files, a statement of the
400 | additional terms that apply to those files, or a notice indicating
401 | where to find the applicable terms.
402 | 
403 |   Additional terms, permissive or non-permissive, may be stated in the
404 | form of a separately written license, or stated as exceptions;
405 | the above requirements apply either way.
406 | 
407 |   8. Termination.
408 | 
409 |   You may not propagate or modify a covered work except as expressly
410 | provided under this License.  Any attempt otherwise to propagate or
411 | modify it is void, and will automatically terminate your rights under
412 | this License (including any patent licenses granted under the third
413 | paragraph of section 11).
414 | 
415 |   However, if you cease all violation of this License, then your
416 | license from a particular copyright holder is reinstated (a)
417 | provisionally, unless and until the copyright holder explicitly and
418 | finally terminates your license, and (b) permanently, if the copyright
419 | holder fails to notify you of the violation by some reasonable means
420 | prior to 60 days after the cessation.
421 | 
422 |   Moreover, your license from a particular copyright holder is
423 | reinstated permanently if the copyright holder notifies you of the
424 | violation by some reasonable means, this is the first time you have
425 | received notice of violation of this License (for any work) from that
426 | copyright holder, and you cure the violation prior to 30 days after
427 | your receipt of the notice.
428 | 
429 |   Termination of your rights under this section does not terminate the
430 | licenses of parties who have received copies or rights from you under
431 | this License.  If your rights have been terminated and not permanently
432 | reinstated, you do not qualify to receive new licenses for the same
433 | material under section 10.
434 | 
435 |   9. Acceptance Not Required for Having Copies.
436 | 
437 |   You are not required to accept this License in order to receive or
438 | run a copy of the Program.  Ancillary propagation of a covered work
439 | occurring solely as a consequence of using peer-to-peer transmission
440 | to receive a copy likewise does not require acceptance.  However,
441 | nothing other than this License grants you permission to propagate or
442 | modify any covered work.  These actions infringe copyright if you do
443 | not accept this License.  Therefore, by modifying or propagating a
444 | covered work, you indicate your acceptance of this License to do so.
445 | 
446 |   10. Automatic Licensing of Downstream Recipients.
447 | 
448 |   Each time you convey a covered work, the recipient automatically
449 | receives a license from the original licensors, to run, modify and
450 | propagate that work, subject to this License.  You are not responsible
451 | for enforcing compliance by third parties with this License.
452 | 
453 |   An "entity transaction" is a transaction transferring control of an
454 | organization, or substantially all assets of one, or subdividing an
455 | organization, or merging organizations.  If propagation of a covered
456 | work results from an entity transaction, each party to that
457 | transaction who receives a copy of the work also receives whatever
458 | licenses to the work the party's predecessor in interest had or could
459 | give under the previous paragraph, plus a right to possession of the
460 | Corresponding Source of the work from the predecessor in interest, if
461 | the predecessor has it or can get it with reasonable efforts.
462 | 
463 |   You may not impose any further restrictions on the exercise of the
464 | rights granted or affirmed under this License.  For example, you may
465 | not impose a license fee, royalty, or other charge for exercise of
466 | rights granted under this License, and you may not initiate litigation
467 | (including a cross-claim or counterclaim in a lawsuit) alleging that
468 | any patent claim is infringed by making, using, selling, offering for
469 | sale, or importing the Program or any portion of it.
470 | 
471 |   11. Patents.
472 | 
473 |   A "contributor" is a copyright holder who authorizes use under this
474 | License of the Program or a work on which the Program is based.  The
475 | work thus licensed is called the contributor's "contributor version".
476 | 
477 |   A contributor's "essential patent claims" are all patent claims
478 | owned or controlled by the contributor, whether already acquired or
479 | hereafter acquired, that would be infringed by some manner, permitted
480 | by this License, of making, using, or selling its contributor version,
481 | but do not include claims that would be infringed only as a
482 | consequence of further modification of the contributor version.  For
483 | purposes of this definition, "control" includes the right to grant
484 | patent sublicenses in a manner consistent with the requirements of
485 | this License.
486 | 
487 |   Each contributor grants you a non-exclusive, worldwide, royalty-free
488 | patent license under the contributor's essential patent claims, to
489 | make, use, sell, offer for sale, import and otherwise run, modify and
490 | propagate the contents of its contributor version.
491 | 
492 |   In the following three paragraphs, a "patent license" is any express
493 | agreement or commitment, however denominated, not to enforce a patent
494 | (such as an express permission to practice a patent or covenant not to
495 | sue for patent infringement).  To "grant" such a patent license to a
496 | party means to make such an agreement or commitment not to enforce a
497 | patent against the party.
498 | 
499 |   If you convey a covered work, knowingly relying on a patent license,
500 | and the Corresponding Source of the work is not available for anyone
501 | to copy, free of charge and under the terms of this License, through a
502 | publicly available network server or other readily accessible means,
503 | then you must either (1) cause the Corresponding Source to be so
504 | available, or (2) arrange to deprive yourself of the benefit of the
505 | patent license for this particular work, or (3) arrange, in a manner
506 | consistent with the requirements of this License, to extend the patent
507 | license to downstream recipients.  "Knowingly relying" means you have
508 | actual knowledge that, but for the patent license, your conveying the
509 | covered work in a country, or your recipient's use of the covered work
510 | in a country, would infringe one or more identifiable patents in that
511 | country that you have reason to believe are valid.
512 | 
513 |   If, pursuant to or in connection with a single transaction or
514 | arrangement, you convey, or propagate by procuring conveyance of, a
515 | covered work, and grant a patent license to some of the parties
516 | receiving the covered work authorizing them to use, propagate, modify
517 | or convey a specific copy of the covered work, then the patent license
518 | you grant is automatically extended to all recipients of the covered
519 | work and works based on it.
520 | 
521 |   A patent license is "discriminatory" if it does not include within
522 | the scope of its coverage, prohibits the exercise of, or is
523 | conditioned on the non-exercise of one or more of the rights that are
524 | specifically granted under this License.  You may not convey a covered
525 | work if you are a party to an arrangement with a third party that is
526 | in the business of distributing software, under which you make payment
527 | to the third party based on the extent of your activity of conveying
528 | the work, and under which the third party grants, to any of the
529 | parties who would receive the covered work from you, a discriminatory
530 | patent license (a) in connection with copies of the covered work
531 | conveyed by you (or copies made from those copies), or (b) primarily
532 | for and in connection with specific products or compilations that
533 | contain the covered work, unless you entered into that arrangement,
534 | or that patent license was granted, prior to 28 March 2007.
535 | 
536 |   Nothing in this License shall be construed as excluding or limiting
537 | any implied license or other defenses to infringement that may
538 | otherwise be available to you under applicable patent law.
539 | 
540 |   12. No Surrender of Others' Freedom.
541 | 
542 |   If conditions are imposed on you (whether by court order, agreement or
543 | otherwise) that contradict the conditions of this License, they do not
544 | excuse you from the conditions of this License.  If you cannot convey a
545 | covered work so as to satisfy simultaneously your obligations under this
546 | License and any other pertinent obligations, then as a consequence you may
547 | not convey it at all.  For example, if you agree to terms that obligate you
548 | to collect a royalty for further conveying from those to whom you convey
549 | the Program, the only way you could satisfy both those terms and this
550 | License would be to refrain entirely from conveying the Program.
551 | 
552 |   13. Use with the GNU Affero General Public License.
553 | 
554 |   Notwithstanding any other provision of this License, you have
555 | permission to link or combine any covered work with a work licensed
556 | under version 3 of the GNU Affero General Public License into a single
557 | combined work, and to convey the resulting work.  The terms of this
558 | License will continue to apply to the part which is the covered work,
559 | but the special requirements of the GNU Affero General Public License,
560 | section 13, concerning interaction through a network will apply to the
561 | combination as such.
562 | 
563 |   14. Revised Versions of this License.
564 | 
565 |   The Free Software Foundation may publish revised and/or new versions of
566 | the GNU General Public License from time to time.  Such new versions will
567 | be similar in spirit to the present version, but may differ in detail to
568 | address new problems or concerns.
569 | 
570 |   Each version is given a distinguishing version number.  If the
571 | Program specifies that a certain numbered version of the GNU General
572 | Public License "or any later version" applies to it, you have the
573 | option of following the terms and conditions either of that numbered
574 | version or of any later version published by the Free Software
575 | Foundation.  If the Program does not specify a version number of the
576 | GNU General Public License, you may choose any version ever published
577 | by the Free Software Foundation.
578 | 
579 |   If the Program specifies that a proxy can decide which future
580 | versions of the GNU General Public License can be used, that proxy's
581 | public statement of acceptance of a version permanently authorizes you
582 | to choose that version for the Program.
583 | 
584 |   Later license versions may give you additional or different
585 | permissions.  However, no additional obligations are imposed on any
586 | author or copyright holder as a result of your choosing to follow a
587 | later version.
588 | 
589 |   15. Disclaimer of Warranty.
590 | 
591 |   THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
592 | APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
596 | PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
597 | IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
599 | 
600 |   16. Limitation of Liability.
601 | 
602 |   IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
610 | SUCH DAMAGES.
611 | 
612 |   17. Interpretation of Sections 15 and 16.
613 | 
614 |   If the disclaimer of warranty and limitation of liability provided
615 | above cannot be given local legal effect according to their terms,
616 | reviewing courts shall apply local law that most closely approximates
617 | an absolute waiver of all civil liability in connection with the
618 | Program, unless a warranty or assumption of liability accompanies a
619 | copy of the Program in return for a fee.
620 | 
621 |                      END OF TERMS AND CONDITIONS
622 | 
623 |             How to Apply These Terms to Your New Programs
624 | 
625 |   If you develop a new program, and you want it to be of the greatest
626 | possible use to the public, the best way to achieve this is to make it
627 | free software which everyone can redistribute and change under these terms.
628 | 
629 |   To do so, attach the following notices to the program.  It is safest
630 | to attach them to the start of each source file to most effectively
631 | state the exclusion of warranty; and each file should have at least
632 | the "copyright" line and a pointer to where the full notice is found.
633 | 
634 |     {one line to give the program's name and a brief idea of what it does.}
635 |     Copyright (C) {year}  {name of author}
636 | 
637 |     This program is free software: you can redistribute it and/or modify
638 |     it under the terms of the GNU General Public License as published by
639 |     the Free Software Foundation, either version 3 of the License, or
640 |     (at your option) any later version.
641 | 
642 |     This program is distributed in the hope that it will be useful,
643 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
644 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
645 |     GNU General Public License for more details.
646 | 
647 |     You should have received a copy of the GNU General Public License
648 |     along with this program.  If not, see <http://www.gnu.org/licenses/>.
649 | 
650 | Also add information on how to contact you by electronic and paper mail.
651 | 
652 |   If the program does terminal interaction, make it output a short
653 | notice like this when it starts in an interactive mode:
654 | 
655 |     libshe  Copyright (C) 2015  Bogdan Kulynych
656 |     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
657 |     This is free software, and you are welcome to redistribute it
658 |     under certain conditions; type `show c' for details.
659 | 
660 | The hypothetical commands `show w' and `show c' should show the appropriate
661 | parts of the General Public License.  Of course, your program's commands
662 | might be different; for a GUI interface, you would use an "about box".
663 | 
664 |   You should also get your employer (if you work as a programmer) or school,
665 | if any, to sign a "copyright disclaimer" for the program, if necessary.
666 | For more information on this, and how to apply and follow the GNU GPL, see
667 | <http://www.gnu.org/licenses/>.
668 | 
669 |   The GNU General Public License does not permit incorporating your program
670 | into proprietary programs.  If your program is a subroutine library, you
671 | may consider it more useful to permit linking proprietary applications with
672 | the library.  If this is what you want to do, use the GNU Lesser General
673 | Public License instead of this License.  But first, please read
674 | <http://www.gnu.org/philosophy/why-not-lgpl.html>.
675 | 


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