├── README.md
├── strenc.nimble
└── src
    └── strenc.nim


/README.md:
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1 | # nim-strenc
2 | string encryption in Nim
3 | 


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/strenc.nimble:
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 1 | # Package
 2 | version       = "0.0.1"
 3 | author        = "Original author removed the code"
 4 | description   = "A library to automatically encrypt all string constants in your programs"
 5 | license       = "MIT"
 6 | srcDir        = "src"
 7 | 
 8 | # Dependencies
 9 | requires "nim >= 1.0.0"
10 | 


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/src/strenc.nim:
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 1 | # Code is based on https://forum.nim-lang.org/t/1305
 2 | # and https://forum.nim-lang.org/t/338
 3 | import macros, hashes
 4 | 
 5 | type
 6 |   # Use a distinct string type so we won't recurse forever
 7 |   estring = distinct string
 8 | 
 9 | # Use a "strange" name
10 | proc gkkaekgaEE(s: estring, key: int): string {.noinline.} =
11 |   # We need {.noinline.} here because otherwise C compiler
12 |   # aggresively inlines this procedure for EACH string which results
13 |   # in more assembly instructions
14 |   var k = key
15 |   result = string(s)
16 |   for i in 0 ..< result.len:
17 |     for f in [0, 8, 16, 24]:
18 |       result[i] = chr(uint8(result[i]) xor uint8((k shr f) and 0xFF))
19 |     k = k +% 1
20 | 
21 | var encodedCounter {.compileTime.} = hash(CompileTime & CompileDate) and 0x7FFFFFFF
22 | 
23 | # Use a term-rewriting macro to change all string literals
24 | macro encrypt*{s}(s: string{lit}): untyped =
25 |   var encodedStr = gkkaekgaEE(estring($s), encodedCounter)
26 | 
27 |   template genStuff(str, counter: untyped): untyped = 
28 |     {.noRewrite.}:
29 |       gkkaekgaEE(estring(`str`), `counter`)
30 |   
31 |   result = getAst(genStuff(encodedStr, encodedCounter))
32 |   encodedCounter = (encodedCounter *% 16777619) and 0x7FFFFFFF
33 | 


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