When this is set as the head of the list, 22 | * an instance of it can function as a drop-in replacement for {@link android.util.Log}. 23 | * Most of the methods in this class server only to map a method call in Log to its equivalent 24 | * in LogNode.
25 | */ 26 | public class Log { 27 | // Grabbing the native values from Android's native logging facilities, 28 | // to make for easy migration and interop. 29 | public static final int NONE = -1; 30 | public static final int VERBOSE = android.util.Log.VERBOSE; 31 | public static final int DEBUG = android.util.Log.DEBUG; 32 | public static final int INFO = android.util.Log.INFO; 33 | public static final int WARN = android.util.Log.WARN; 34 | public static final int ERROR = android.util.Log.ERROR; 35 | public static final int ASSERT = android.util.Log.ASSERT; 36 | 37 | // Stores the beginning of the LogNode topology. 38 | private static LogNode mLogNode; 39 | 40 | /** 41 | * Returns the next LogNode in the linked list. 42 | */ 43 | public static LogNode getLogNode() { 44 | return mLogNode; 45 | } 46 | 47 | /** 48 | * Sets the LogNode data will be sent to. 49 | */ 50 | public static void setLogNode(LogNode node) { 51 | mLogNode = node; 52 | } 53 | 54 | /** 55 | * Instructs the LogNode to print the log data provided. Other LogNodes can 56 | * be chained to the end of the LogNode as desired. 57 | * 58 | * @param priority Log level of the data being logged. Verbose, Error, etc. 59 | * @param tag Tag for for the log data. Can be used to organize log statements. 60 | * @param msg The actual message to be logged. 61 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 62 | * to extract and print useful information. 63 | */ 64 | public static void println(int priority, String tag, String msg, Throwable tr) { 65 | if (mLogNode != null) { 66 | mLogNode.println(priority, tag, msg, tr); 67 | } 68 | } 69 | 70 | /** 71 | * Instructs the LogNode to print the log data provided. Other LogNodes can 72 | * be chained to the end of the LogNode as desired. 73 | * 74 | * @param priority Log level of the data being logged. Verbose, Error, etc. 75 | * @param tag Tag for for the log data. Can be used to organize log statements. 76 | * @param msg The actual message to be logged. The actual message to be logged. 77 | */ 78 | public static void println(int priority, String tag, String msg) { 79 | println(priority, tag, msg, null); 80 | } 81 | 82 | /** 83 | * Prints a message at VERBOSE priority. 84 | * 85 | * @param tag Tag for for the log data. Can be used to organize log statements. 86 | * @param msg The actual message to be logged. 87 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 88 | * to extract and print useful information. 89 | */ 90 | public static void v(String tag, String msg, Throwable tr) { 91 | println(VERBOSE, tag, msg, tr); 92 | } 93 | 94 | /** 95 | * Prints a message at VERBOSE priority. 96 | * 97 | * @param tag Tag for for the log data. Can be used to organize log statements. 98 | * @param msg The actual message to be logged. 99 | */ 100 | public static void v(String tag, String msg) { 101 | v(tag, msg, null); 102 | } 103 | 104 | 105 | /** 106 | * Prints a message at DEBUG priority. 107 | * 108 | * @param tag Tag for for the log data. Can be used to organize log statements. 109 | * @param msg The actual message to be logged. 110 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 111 | * to extract and print useful information. 112 | */ 113 | public static void d(String tag, String msg, Throwable tr) { 114 | println(DEBUG, tag, msg, tr); 115 | } 116 | 117 | /** 118 | * Prints a message at DEBUG priority. 119 | * 120 | * @param tag Tag for for the log data. Can be used to organize log statements. 121 | * @param msg The actual message to be logged. 122 | */ 123 | public static void d(String tag, String msg) { 124 | d(tag, msg, null); 125 | } 126 | 127 | /** 128 | * Prints a message at INFO priority. 129 | * 130 | * @param tag Tag for for the log data. Can be used to organize log statements. 131 | * @param msg The actual message to be logged. 132 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 133 | * to extract and print useful information. 134 | */ 135 | public static void i(String tag, String msg, Throwable tr) { 136 | println(INFO, tag, msg, tr); 137 | } 138 | 139 | /** 140 | * Prints a message at INFO priority. 141 | * 142 | * @param tag Tag for for the log data. Can be used to organize log statements. 143 | * @param msg The actual message to be logged. 144 | */ 145 | public static void i(String tag, String msg) { 146 | i(tag, msg, null); 147 | } 148 | 149 | /** 150 | * Prints a message at WARN priority. 151 | * 152 | * @param tag Tag for for the log data. Can be used to organize log statements. 153 | * @param msg The actual message to be logged. 154 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 155 | * to extract and print useful information. 156 | */ 157 | public static void w(String tag, String msg, Throwable tr) { 158 | println(WARN, tag, msg, tr); 159 | } 160 | 161 | /** 162 | * Prints a message at WARN priority. 163 | * 164 | * @param tag Tag for for the log data. Can be used to organize log statements. 165 | * @param msg The actual message to be logged. 166 | */ 167 | public static void w(String tag, String msg) { 168 | w(tag, msg, null); 169 | } 170 | 171 | /** 172 | * Prints a message at WARN priority. 173 | * 174 | * @param tag Tag for for the log data. Can be used to organize log statements. 175 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 176 | * to extract and print useful information. 177 | */ 178 | public static void w(String tag, Throwable tr) { 179 | w(tag, null, tr); 180 | } 181 | 182 | /** 183 | * Prints a message at ERROR priority. 184 | * 185 | * @param tag Tag for for the log data. Can be used to organize log statements. 186 | * @param msg The actual message to be logged. 187 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 188 | * to extract and print useful information. 189 | */ 190 | public static void e(String tag, String msg, Throwable tr) { 191 | println(ERROR, tag, msg, tr); 192 | } 193 | 194 | /** 195 | * Prints a message at ERROR priority. 196 | * 197 | * @param tag Tag for for the log data. Can be used to organize log statements. 198 | * @param msg The actual message to be logged. 199 | */ 200 | public static void e(String tag, String msg) { 201 | e(tag, msg, null); 202 | } 203 | 204 | /** 205 | * Prints a message at ASSERT priority. 206 | * 207 | * @param tag Tag for for the log data. Can be used to organize log statements. 208 | * @param msg The actual message to be logged. 209 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 210 | * to extract and print useful information. 211 | */ 212 | public static void wtf(String tag, String msg, Throwable tr) { 213 | println(ASSERT, tag, msg, tr); 214 | } 215 | 216 | /** 217 | * Prints a message at ASSERT priority. 218 | * 219 | * @param tag Tag for for the log data. Can be used to organize log statements. 220 | * @param msg The actual message to be logged. 221 | */ 222 | public static void wtf(String tag, String msg) { 223 | wtf(tag, msg, null); 224 | } 225 | 226 | /** 227 | * Prints a message at ASSERT priority. 228 | * 229 | * @param tag Tag for for the log data. Can be used to organize log statements. 230 | * @param tr If an exception was thrown, this can be sent along for the logging facilities 231 | * to extract and print useful information. 232 | */ 233 | public static void wtf(String tag, Throwable tr) { 234 | wtf(tag, null, tr); 235 | } 236 | } 237 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | -------------- 3 | 4 | Version 2.0, January 2004 5 | http://www.apache.org/licenses/ 6 | 7 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 8 | 9 | 1. 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The string used to refer to the Key you 66 | // want to store, or later pull, is referred to as an "alias" in this case, because calling it 67 | // a key, when you use it to retrieve a key, would just be irritating. 68 | private String mAlias = null; 69 | 70 | // END_INCLUDE(values) 71 | 72 | @Override 73 | public void onCreate(Bundle savedInstanceState) { 74 | super.onCreate(savedInstanceState); 75 | setHasOptionsMenu(true); 76 | setAlias(SAMPLE_ALIAS); 77 | } 78 | 79 | @Override 80 | public void onActivityCreated(Bundle savedInstanceState) { 81 | super.onActivityCreated(savedInstanceState); 82 | } 83 | 84 | @Override 85 | public boolean onOptionsItemSelected(MenuItem item) { 86 | switch (item.getItemId()) { 87 | case R.id.btn_create_keys: 88 | try { 89 | createKeys(getActivity()); 90 | Log.d(TAG, "Keys created"); 91 | return true; 92 | } catch (NoSuchAlgorithmException e) { 93 | Log.w(TAG, "RSA not supported", e); 94 | } catch (InvalidAlgorithmParameterException e) { 95 | Log.w(TAG, "No such provider: AndroidKeyStore"); 96 | } catch (NoSuchProviderException e) { 97 | Log.w(TAG, "Invalid Algorithm Parameter Exception", e); 98 | } 99 | return true; 100 | case R.id.btn_sign_data: 101 | try { 102 | mSignatureStr = signData(SAMPLE_INPUT); 103 | } catch (KeyStoreException e) { 104 | Log.w(TAG, "KeyStore not Initialized", e); 105 | } catch (UnrecoverableEntryException e) { 106 | Log.w(TAG, "KeyPair not recovered", e); 107 | } catch (NoSuchAlgorithmException e) { 108 | Log.w(TAG, "RSA not supported", e); 109 | } catch (InvalidKeyException e) { 110 | Log.w(TAG, "Invalid Key", e); 111 | } catch (SignatureException e) { 112 | Log.w(TAG, "Invalid Signature", e); 113 | } catch (IOException e) { 114 | Log.w(TAG, "IO Exception", e); 115 | } catch (CertificateException e) { 116 | Log.w(TAG, "Error occurred while loading certificates", e); 117 | } 118 | Log.d(TAG, "Signature: " + mSignatureStr); 119 | return true; 120 | 121 | case R.id.btn_verify_data: 122 | boolean verified = false; 123 | try { 124 | if (mSignatureStr != null) { 125 | verified = verifyData(SAMPLE_INPUT, mSignatureStr); 126 | } 127 | } catch (KeyStoreException e) { 128 | Log.w(TAG, "KeyStore not Initialized", e); 129 | } catch (CertificateException e) { 130 | Log.w(TAG, "Error occurred while loading certificates", e); 131 | } catch (NoSuchAlgorithmException e) { 132 | Log.w(TAG, "RSA not supported", e); 133 | } catch (IOException e) { 134 | Log.w(TAG, "IO Exception", e); 135 | } catch (UnrecoverableEntryException e) { 136 | Log.w(TAG, "KeyPair not recovered", e); 137 | } catch (InvalidKeyException e) { 138 | Log.w(TAG, "Invalid Key", e); 139 | } catch (SignatureException e) { 140 | Log.w(TAG, "Invalid Signature", e); 141 | } 142 | if (verified) { 143 | Log.d(TAG, "Data Signature Verified"); 144 | } else { 145 | Log.d(TAG, "Data not verified."); 146 | } 147 | return true; 148 | } 149 | return false; 150 | } 151 | 152 | /** 153 | * Creates a public and private key and stores it using the Android Key Store, so that only 154 | * this application will be able to access the keys. 155 | */ 156 | public void createKeys(Context context) throws NoSuchProviderException, 157 | NoSuchAlgorithmException, InvalidAlgorithmParameterException { 158 | // BEGIN_INCLUDE(create_valid_dates) 159 | // Create a start and end time, for the validity range of the key pair that's about to be 160 | // generated. 161 | Calendar start = new GregorianCalendar(); 162 | Calendar end = new GregorianCalendar(); 163 | end.add(Calendar.YEAR, 1); 164 | //END_INCLUDE(create_valid_dates) 165 | 166 | // BEGIN_INCLUDE(create_keypair) 167 | // Initialize a KeyPair generator using the the intended algorithm (in this example, RSA 168 | // and the KeyStore. This example uses the AndroidKeyStore. 169 | KeyPairGenerator kpGenerator = KeyPairGenerator 170 | .getInstance(SecurityConstants.TYPE_RSA, 171 | SecurityConstants.KEYSTORE_PROVIDER_ANDROID_KEYSTORE); 172 | // END_INCLUDE(create_keypair) 173 | 174 | // BEGIN_INCLUDE(create_spec) 175 | // The KeyPairGeneratorSpec object is how parameters for your key pair are passed 176 | // to the KeyPairGenerator. 177 | AlgorithmParameterSpec spec; 178 | 179 | if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) { 180 | // Below Android M, use the KeyPairGeneratorSpec.Builder. 181 | 182 | spec = new KeyPairGeneratorSpec.Builder(context) 183 | // You'll use the alias later to retrieve the key. It's a key for the key! 184 | .setAlias(mAlias) 185 | // The subject used for the self-signed certificate of the generated pair 186 | .setSubject(new X500Principal("CN=" + mAlias)) 187 | // The serial number used for the self-signed certificate of the 188 | // generated pair. 189 | .setSerialNumber(BigInteger.valueOf(1337)) 190 | // Date range of validity for the generated pair. 191 | .setStartDate(start.getTime()) 192 | .setEndDate(end.getTime()) 193 | .build(); 194 | 195 | 196 | } else { 197 | // On Android M or above, use the KeyGenparameterSpec.Builder and specify permitted 198 | // properties and restrictions of the key. 199 | spec = new KeyGenParameterSpec.Builder(mAlias, KeyProperties.PURPOSE_SIGN) 200 | .setCertificateSubject(new X500Principal("CN=" + mAlias)) 201 | .setDigests(KeyProperties.DIGEST_SHA256) 202 | .setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1) 203 | .setCertificateSerialNumber(BigInteger.valueOf(1337)) 204 | .setCertificateNotBefore(start.getTime()) 205 | .setCertificateNotAfter(end.getTime()) 206 | .build(); 207 | } 208 | 209 | kpGenerator.initialize(spec); 210 | 211 | KeyPair kp = kpGenerator.generateKeyPair(); 212 | // END_INCLUDE(create_spec) 213 | Log.d(TAG, "Public Key is: " + kp.getPublic().toString()); 214 | } 215 | 216 | /** 217 | * Signs the data using the key pair stored in the Android Key Store. This signature can be 218 | * used with the data later to verify it was signed by this application. 219 | * @return A string encoding of the data signature generated 220 | */ 221 | public String signData(String inputStr) throws KeyStoreException, 222 | UnrecoverableEntryException, NoSuchAlgorithmException, InvalidKeyException, 223 | SignatureException, IOException, CertificateException { 224 | byte[] data = inputStr.getBytes(); 225 | 226 | // BEGIN_INCLUDE(sign_load_keystore) 227 | KeyStore ks = KeyStore.getInstance(SecurityConstants.KEYSTORE_PROVIDER_ANDROID_KEYSTORE); 228 | 229 | // Weird artifact of Java API. If you don't have an InputStream to load, you still need 230 | // to call "load", or it'll crash. 231 | ks.load(null); 232 | 233 | // Load the key pair from the Android Key Store 234 | KeyStore.Entry entry = ks.getEntry(mAlias, null); 235 | 236 | /* If the entry is null, keys were never stored under this alias. 237 | * Debug steps in this situation would be: 238 | * -Check the list of aliases by iterating over Keystore.aliases(), be sure the alias 239 | * exists. 240 | * -If that's empty, verify they were both stored and pulled from the same keystore 241 | * "AndroidKeyStore" 242 | */ 243 | if (entry == null) { 244 | Log.w(TAG, "No key found under alias: " + mAlias); 245 | Log.w(TAG, "Exiting signData()..."); 246 | return null; 247 | } 248 | 249 | /* If entry is not a KeyStore.PrivateKeyEntry, it might have gotten stored in a previous 250 | * iteration of your application that was using some other mechanism, or been overwritten 251 | * by something else using the same keystore with the same alias. 252 | * You can determine the type using entry.getClass() and debug from there. 253 | */ 254 | if (!(entry instanceof KeyStore.PrivateKeyEntry)) { 255 | Log.w(TAG, "Not an instance of a PrivateKeyEntry"); 256 | Log.w(TAG, "Exiting signData()..."); 257 | return null; 258 | } 259 | // END_INCLUDE(sign_data) 260 | 261 | // BEGIN_INCLUDE(sign_create_signature) 262 | // This class doesn't actually represent the signature, 263 | // just the engine for creating/verifying signatures, using 264 | // the specified algorithm. 265 | Signature s = Signature.getInstance(SecurityConstants.SIGNATURE_SHA256withRSA); 266 | 267 | // Initialize Signature using specified private key 268 | s.initSign(((KeyStore.PrivateKeyEntry) entry).getPrivateKey()); 269 | 270 | // Sign the data, store the result as a Base64 encoded String. 271 | s.update(data); 272 | byte[] signature = s.sign(); 273 | String result = Base64.encodeToString(signature, Base64.DEFAULT); 274 | // END_INCLUDE(sign_data) 275 | 276 | return result; 277 | } 278 | 279 | /** 280 | * Given some data and a signature, uses the key pair stored in the Android Key Store to verify 281 | * that the data was signed by this application, using that key pair. 282 | * @param input The data to be verified. 283 | * @param signatureStr The signature provided for the data. 284 | * @return A boolean value telling you whether the signature is valid or not. 285 | */ 286 | public boolean verifyData(String input, String signatureStr) throws KeyStoreException, 287 | CertificateException, NoSuchAlgorithmException, IOException, 288 | UnrecoverableEntryException, InvalidKeyException, SignatureException { 289 | byte[] data = input.getBytes(); 290 | byte[] signature; 291 | // BEGIN_INCLUDE(decode_signature) 292 | 293 | // Make sure the signature string exists. If not, bail out, nothing to do. 294 | 295 | if (signatureStr == null) { 296 | Log.w(TAG, "Invalid signature."); 297 | Log.w(TAG, "Exiting verifyData()..."); 298 | return false; 299 | } 300 | 301 | try { 302 | // The signature is going to be examined as a byte array, 303 | // not as a base64 encoded string. 304 | signature = Base64.decode(signatureStr, Base64.DEFAULT); 305 | } catch (IllegalArgumentException e) { 306 | // signatureStr wasn't null, but might not have been encoded properly. 307 | // It's not a valid Base64 string. 308 | return false; 309 | } 310 | // END_INCLUDE(decode_signature) 311 | 312 | KeyStore ks = KeyStore.getInstance("AndroidKeyStore"); 313 | 314 | // Weird artifact of Java API. If you don't have an InputStream to load, you still need 315 | // to call "load", or it'll crash. 316 | ks.load(null); 317 | 318 | // Load the key pair from the Android Key Store 319 | KeyStore.Entry entry = ks.getEntry(mAlias, null); 320 | 321 | if (entry == null) { 322 | Log.w(TAG, "No key found under alias: " + mAlias); 323 | Log.w(TAG, "Exiting verifyData()..."); 324 | return false; 325 | } 326 | 327 | if (!(entry instanceof KeyStore.PrivateKeyEntry)) { 328 | Log.w(TAG, "Not an instance of a PrivateKeyEntry"); 329 | return false; 330 | } 331 | 332 | // This class doesn't actually represent the signature, 333 | // just the engine for creating/verifying signatures, using 334 | // the specified algorithm. 335 | Signature s = Signature.getInstance(SecurityConstants.SIGNATURE_SHA256withRSA); 336 | 337 | // BEGIN_INCLUDE(verify_data) 338 | // Verify the data. 339 | s.initVerify(((KeyStore.PrivateKeyEntry) entry).getCertificate()); 340 | s.update(data); 341 | return s.verify(signature); 342 | // END_INCLUDE(verify_data) 343 | } 344 | 345 | public void setAlias(String alias) { 346 | mAlias = alias; 347 | } 348 | } 349 | --------------------------------------------------------------------------------