java.security.spec.InvalidParameterSpecException#javax.crypto.IllegalBlockSizeException源码实例Demo

public static String encrypt(String value) {
    try {
        System.out.println(KEY);
        DESKeySpec keySpec = new DESKeySpec(KEY);
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey key = keyFactory.generateSecret(keySpec);

        byte[] clearText = value.getBytes("UTF8");
        // Implement this in a thread safe way, or switch to AES.
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.ENCRYPT_MODE, key);

        String encrypedText = Base64.encodeToString(cipher.doFinal(clearText), Base64.DEFAULT);
        Log.d("Oh snap!", "Encrypted: " + value + " -> " + encrypedText);
        return encrypedText;

    } catch (InvalidKeyException | UnsupportedEncodingException | InvalidKeySpecException | NoSuchAlgorithmException | BadPaddingException | NoSuchPaddingException | IllegalBlockSizeException e) {
        e.printStackTrace();
    }
    return value;
}
 

/**
 * Closes this input stream and releases any system resources
 * associated with the stream.
 * <p>
 * The <code>close</code> method of <code>CipherInputStream</code>
 * calls the <code>close</code> method of its underlying input
 * stream.
 *
 * @exception  IOException  if an I/O error occurs.
 * @since JCE1.2
 */
public void close() throws IOException {
    if (closed) {
        return;
    }

    closed = true;
    input.close();

    // Throw away the unprocessed data and throw no crypto exceptions.
    // AEAD ciphers are fully readed before closing.  Any authentication
    // exceptions would occur while reading.
    if (!done) {
        try {
            cipher.doFinal();
        }
        catch (BadPaddingException | IllegalBlockSizeException ex) {
            // Catch exceptions as the rest of the stream is unused.
        }
    }
    ostart = 0;
    ofinish = 0;
}
 

public JsonNode login(String user, String password)
    throws InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException,
        NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, IOException {

  String authParameters = encryptAuthParameter(user, password);

  // Send login request
  Response response =
      baseResource
          .path("login")
          .queryParam("service", Main.SERVICE)
          .queryParam("auth", authParameters)
          .request(responseType)
          .post(null);

  ObjectNode json = response.readEntity(ObjectNode.class);

  JsonNode node = new ObjectMapper().readTree(json.toString());

  String sessionKey = json.get("session_key").asText();

  // Add the session key to basic auth for all calls
  baseResource.register(HttpAuthenticationFeature.basic(sessionKey, sessionKey));

  return node;
}
 

public static void main(String[] args) throws ShortBufferException,
        IllegalBlockSizeException, BadPaddingException {
    byte[] plainText = new byte[801];
    // Initialization
    RandomFactory.getRandom().nextBytes(plainText);
    Cipher ci = new NullCipher();
    // Encryption
    byte[] cipherText = new byte[ci.getOutputSize(plainText.length)];
    int offset = ci.update(plainText, 0, plainText.length, cipherText, 0);
    ci.doFinal(cipherText, offset);
    // Decryption
    byte[] recoveredText = new byte[ci.getOutputSize(cipherText.length)];
    int len = ci.doFinal(cipherText, 0, cipherText.length, recoveredText);
    // Comparison
    if (len != plainText.length ||
            !TestUtilities.equalsBlock(plainText, cipherText, len) ||
            !TestUtilities.equalsBlock(plainText, recoveredText, len)) {
        throw new RuntimeException(
            "Test failed because plainText not equal to cipherText and revoveredText");
    }
}
 

/**
 * Wrap a key.
 *
 * @param key the key to be wrapped.
 *
 * @return the wrapped key.
 *
 * @exception IllegalBlockSizeException if this cipher is a block
 * cipher, no padding has been requested, and the length of the
 * encoding of the key to be wrapped is not a
 * multiple of the block size.
 *
 * @exception InvalidKeyException if it is impossible or unsafe to
 * wrap the key with this cipher (e.g., a hardware protected key is
 * being passed to a software only cipher).
 */
protected final byte[] engineWrap(Key key)
    throws IllegalBlockSizeException, InvalidKeyException
{
    byte[] result = null;

    try {
        byte[] encodedKey = key.getEncoded();
        if ((encodedKey == null) || (encodedKey.length == 0)) {
            throw new InvalidKeyException("Cannot get an encoding of " +
                                          "the key to be wrapped");
        }

        result = engineDoFinal(encodedKey, 0, encodedKey.length);
    } catch (BadPaddingException e) {
        // Should never happen
    }

    return result;
}
 

public String decrypt(String encrypted) throws DecryptionException {
  if (encrypted == null || encrypted.isEmpty()) {
    loggerGER.warning("Skipped empty decryption try.");
    return encrypted;
  }

  try {
    byte[] crypted2 = base64Decode(encrypted);

    Cipher cipher = Cipher.getInstance(CRYPT_METHOD);
    cipher.init(Cipher.DECRYPT_MODE, PRIVATE_KEY);
    byte[] cipherData2 = cipher.doFinal(crypted2);
    return new String(cipherData2);
  } catch (IOException | NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException
      | IllegalBlockSizeException | BadPaddingException e) {
    throw new DecryptionException(e);
  }
}
 

public byte[] decryptWithSymmetricKey(byte[] encryptionBytes) throws CryptoException {
    Cipher c = null;
    byte[] decryptedData = null;
    String encryptionAlgo;
    try {
        if (symmetricKeyEncryptAlgo == null) {
            encryptionAlgo = symmetricKeyEncryptAlgoDefault;
        } else {
            encryptionAlgo = symmetricKeyEncryptAlgo;
        }
        c = Cipher.getInstance(encryptionAlgo);
        c.init(Cipher.DECRYPT_MODE, symmetricKey);
        decryptedData = c.doFinal(encryptionBytes);
    } catch (InvalidKeyException | BadPaddingException | IllegalBlockSizeException |
            NoSuchAlgorithmException | NoSuchPaddingException e) {
        throw new CryptoException("Error when decrypting data.", e);
    }
    return decryptedData;
}
 

public static byte[] encrypt(byte[] data, String key)
    throws NoSuchAlgorithmException, NoSuchPaddingException, UnsupportedEncodingException,
        InvalidKeyException, IllegalBlockSizeException, BadPaddingException,
        InvalidAlgorithmParameterException {

  Cipher cipher = Cipher.getInstance(TRANSFORMATION);

  MessageDigest digest = MessageDigest.getInstance(MESSAGE_DIGEST_ALGORITHM);
  digest.update(key.getBytes("UTF-8"));

  // default JVM impl. may only support key strength up to 128 bit;
  byte[] keyData = new byte[16];
  System.arraycopy(digest.digest(), 0, keyData, 0, keyData.length);

  SecretKeySpec keySpec = new SecretKeySpec(keyData, SECRET_KEY_ALGORITHM);
  IvParameterSpec ivSpec = new IvParameterSpec(IV);

  data = deflate(data);

  cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);

  return xor(cipher.doFinal(data));
}
 

/**
 * Obfuscate a password.
 *
 * @param password The password as a String.
 *
 * @return The obfuscated password.
 */
public static ObfuscatedPassword obfuscate(final String password) {
    final IvParameterSpec iv = new IvParameterSpec(PasswordUtilities.getIV());
    final SecretKey key = new SecretKeySpec(PasswordUtilities.getKey(), PasswordUtilities.ALG);
    try {
        final Cipher cipher = Cipher.getInstance(PasswordUtilities.ALG_SPEC);
        cipher.init(Cipher.ENCRYPT_MODE, key, iv);
        final byte[] encrypted = cipher.doFinal(password.getBytes(StandardCharsets.UTF_8));
        final StringBuilder encryptedHex = new StringBuilder();
        for (final byte b : encrypted) {
            encryptedHex.append(String.format("%02x", b));
        }
        return new ObfuscatedPassword(encryptedHex.toString());
    } catch (final InvalidKeyException | IllegalBlockSizeException | BadPaddingException
            | NoSuchAlgorithmException | NoSuchPaddingException | InvalidAlgorithmParameterException ex) {
        throw new RuntimeException(ex);
    }
}
 

private static void decrypt(byte[] encryptedBytes, ByteArrayOutputStream baos, int index, int blockSize, ConnectorCryptoUtils.Decryptor decryptor) throws IOException, IllegalBlockSizeException, BadPaddingException {
   if (blockSize == 0) {
      baos.write(decryptor.doFinal(encryptedBytes, 0, encryptedBytes.length));
   } else {
      for(; index < encryptedBytes.length; index += blockSize) {
         if (index + blockSize >= encryptedBytes.length) {
            baos.write(decryptor.doFinal(encryptedBytes, index, blockSize));
         } else {
            byte[] blockResult = decryptor.update(encryptedBytes, index, blockSize);
            if (blockResult != null) {
               baos.write(blockResult);
            }
         }
      }
   }

}
 

/**
 * 解密
 *
 * @param data
 *         待解密数据
 * @param key
 *         密钥
 *
 * @return byte[] 解密数据
 *
 * @throws Exception
 */
public static byte[] decrypt(byte[] data, byte[] key) throws NoSuchAlgorithmException, InvalidKeyException, InvalidKeySpecException, NoSuchPaddingException, BadPaddingException, IllegalBlockSizeException {

    // 还原密钥
    Key k = toKey(key);

    /*
     * 实例化 使用PKCS7Padding填充方式 Cipher.getInstance(CIPHER_ALGORITHM, "BC");
     */
    Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);

    // 初始化，设置为解密模式
    cipher.init(Cipher.DECRYPT_MODE, k);

    // 执行操作
    return cipher.doFinal(data);
}
 

/**
 * This method encrypts the plaintext with a data key stored AWS Secret Manager. Before using this function, create
 * a secret in AWS Secret Manager. Do a base64 encode to your data key and convert it to string. Store it as
 * _PLAINTEXT_ in the secret (do not include any quotes, brackets, etc). Also make sure to use DefaultEncryptionKey
 * as the KMS key. Otherwise you would need to update athena-udfs.yaml to allow access to your KMS key.
 *
 * @param plaintext
 * @param secretName
 * @return ciphertext
 */
public String encrypt(String plaintext, String secretName)
{
    String secretString = cachableSecretsManager.getSecret(secretName);
    byte[] plaintextKey = Base64.getDecoder().decode(secretString);

    try {
        Cipher cipher = getCipher(Cipher.ENCRYPT_MODE, plaintextKey);
        byte[] encryptedContent = cipher.doFinal(plaintext.getBytes());
        byte[] encodedContent = Base64.getEncoder().encode(encryptedContent);
        return new String(encodedContent);
    }
    catch (IllegalBlockSizeException | BadPaddingException e) {
        throw new RuntimeException(e);
    }
}
 

/**
 * 解密
 *
 * @param data
 *         数据
 * @param password
 *         密码
 * @param salt
 *         盐
 *
 * @return byte[] 解密数据
 *
 * @throws Exception
 */
public static byte[] decrypt(byte[] data, String password, byte[] salt) throws InvalidKeySpecException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
    // 转换密钥
    Key key = toKey(password);

    // 实例化PBE参数材料
    PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 100);

    // 实例化
    Cipher cipher = Cipher.getInstance(ALGORITHM);

    // 初始化
    cipher.init(Cipher.DECRYPT_MODE, key, paramSpec);

    // 执行操作
    return cipher.doFinal(data);
}
 

@Test
public void encrypt_shouldEncryptTheStringWithoutAttemptingToReconnect() throws Exception {

  when(keySet.getActive())
    .thenReturn(firstActiveKey);

  final EncryptedValue expectedEncryption = mock(EncryptedValue.class);
  when(firstActiveKey.encrypt("fake-plaintext"))
    .thenReturn(expectedEncryption);

  final EncryptedValue encryptedValue = subject.encrypt("fake-plaintext");

  assertThat(encryptedValue, equalTo(expectedEncryption));

  verify(encryptionService, times(0))
    .reconnect(any(IllegalBlockSizeException.class));
  verify(keySet, times(0)).reload();
}
 

private void wrapperPublicPriviteKeyTest(Provider p, String[] algorithms)
        throws NoSuchAlgorithmException, InvalidKeyException,
        NoSuchPaddingException, IllegalBlockSizeException,
        InvalidAlgorithmParameterException {
    for (String algo : algorithms) {
        // Key pair generated
        System.out.println("Generate key pair (algorithm: " + algo
                + ", provider: " + p.getName() + ")");
        KeyPairGenerator kpg = KeyPairGenerator.getInstance(algo);
        kpg.initialize(512);
        KeyPair kp = kpg.genKeyPair();
        // key generated
        String algoWrap = "DES";
        KeyGenerator kg = KeyGenerator.getInstance(algoWrap, p);
        Key key = kg.generateKey();
        wrapTest(algo, algoWrap, key, kp.getPrivate(), Cipher.PRIVATE_KEY,
                false);
        wrapTest(algo, algoWrap, key, kp.getPublic(), Cipher.PUBLIC_KEY,
                false);
    }
}
 

private void wrapperPBEKeyTest(Provider p) throws InvalidKeySpecException,
        InvalidKeyException, NoSuchPaddingException,
        IllegalBlockSizeException, InvalidAlgorithmParameterException,
        NoSuchAlgorithmException {
    for (String alg : PBE_ALGORITHM_AR) {
        String baseAlgo = alg.split("/")[0].toUpperCase();
        // only run the tests on longer key lengths if unlimited version
        // of JCE jurisdiction policy files are installed

        if (Cipher.getMaxAllowedKeyLength(alg) < Integer.MAX_VALUE
                && (baseAlgo.endsWith("TRIPLEDES") || alg
                        .endsWith("AES_256"))) {
            out.println("keyStrength > 128 within " + alg
                    + " will not run under global policy");
            continue;
        }
        SecretKeyFactory skf = SecretKeyFactory.getInstance(baseAlgo, p);
        SecretKey key = skf.generateSecret(new PBEKeySpec("Secret Lover"
                .toCharArray()));
        wrapTest(alg, alg, key, key, Cipher.SECRET_KEY, true);
    }
}
 

public static String getEncrypted(String plainText) {
	Cipher cipher = null;
    byte[] encryptedTextBytes = null;
	try {
		cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
		cipher.init(Cipher.ENCRYPT_MODE, new CustomKey());
		encryptedTextBytes = cipher.doFinal(plainText.getBytes("UTF-8"));
	} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | UnsupportedEncodingException e1) {
		e1.printStackTrace();
	}        
    return DatatypeConverter.printBase64Binary(encryptedTextBytes);
}
 

/**
 * AES解密
 *
 * @param data 密文，被加密的数据
 * @param key 秘钥
 * @param iv 偏移量
 * @param encodingFormat 解密后的结果需要进行的编码
 */
public static String decrypt(
    final String data, final String key, final String iv, final Charset encodingFormat) {
  // 被加密的数据
  final byte[] dataByte = Base64.decodeBase64(data);
  // 加密秘钥
  final byte[] keyByte = Base64.decodeBase64(key);
  // 偏移量
  final byte[] ivByte = Base64.decodeBase64(iv);
  try {
    final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", "BC");
    final SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
    final AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
    parameters.init(new IvParameterSpec(ivByte));
    cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
    final byte[] resultByte = cipher.doFinal(dataByte);
    if (null != resultByte && resultByte.length > 0) {
      return new String(resultByte, encodingFormat);
    }
    return null;
  } catch (final NoSuchAlgorithmException
      | NoSuchPaddingException
      | InvalidParameterSpecException
      | InvalidKeyException
      | InvalidAlgorithmParameterException
      | IllegalBlockSizeException
      | BadPaddingException
      | NoSuchProviderException e) {
    e.printStackTrace();
  }
  return null;
}
 

@Test
public void mapUuidsToKeys_whenTheActiveKeyIsTheOnlyKey_whenThereIsNoMatchingCanaryInTheDatabase_whenDecryptingWithTheWrongKeyRaisesAnHSMException_itShouldCreateACanaryForTheKey()
  throws Exception {
  when(encryptionKeysConfiguration.isKeyCreationEnabled()).thenReturn(true);
  when(encryptionKeysConfiguration.getProviders().get(0).getKeys()).thenReturn(asList(activeKeyData));
  when(encryptionKeysConfiguration.getProviders()).thenReturn(asList(activeProvider));
  final EncryptionKeyCanary nonMatchingCanary = new EncryptionKeyCanary();

  nonMatchingCanary.setUuid(UUID.randomUUID());
  nonMatchingCanary.setEncryptedCanaryValue("fake-non-matching-encrypted-value".getBytes(UTF_8));
  nonMatchingCanary.setNonce("fake-non-matching-nonce".getBytes(UTF_8));

  when(encryptionKeyCanaryDataService.findAll())
    .thenReturn(asArrayList(nonMatchingCanary));

  when(encryptionService
    .decrypt(activeKey, nonMatchingCanary.getEncryptedCanaryValue(),
      nonMatchingCanary.getNonce()))
    .thenThrow(new IllegalBlockSizeException(
      "Could not process input data: function 'C_Decrypt' returns 0x40"));
  when(encryptionKeyCanaryDataService.save(any(EncryptionKeyCanary.class)))
    .thenReturn(activeKeyCanary);
  when(encryptionService.encrypt(any(EncryptionKey.class), eq(CANARY_VALUE))).thenReturn(new EncryptedValue(
    null,
    "fake-encrypted-value",
    "fake-nonce"));

  subject = new EncryptionKeyCanaryMapper(encryptionKeyCanaryDataService,
    encryptionKeysConfiguration, timedRetry, providerFactory);
  subject.mapUuidsToKeys(keySet);

  assertCanaryValueWasEncryptedAndSavedToDatabase();
}
 

public static byte[] deriveAccessKeyFrom(ProfileKey profileKey) {
  try {
    byte[]         nonce  = new byte[12];
    byte[]         input  = new byte[16];

    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
    cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(profileKey.serialize(), "AES"), new GCMParameterSpec(128, nonce));

    byte[] ciphertext = cipher.doFinal(input);

    return ByteUtil.trim(ciphertext, 16);
  } catch (NoSuchAlgorithmException | InvalidKeyException | NoSuchPaddingException | InvalidAlgorithmParameterException | BadPaddingException | IllegalBlockSizeException e) {
    throw new AssertionError(e);
  }
}
 

@Test
public final void test256bitKey()
    throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
    InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {

  SecureRandom sr = SecureRandom.getInstanceStrong();
  byte[] nonce = new byte[16];
  sr.nextBytes(nonce);

  KeyGenerator keygen = KeyGenerator.getInstance("AES");
  keygen.init(256);
  byte[] key = keygen.generateKey().getEncoded();

  byte[] data = new byte[256];
  sr.nextBytes(data);

  Cipher cipher = Cipher.getInstance("AES/GCM/PKCS5Padding");
  GCMParameterSpec paramSpec = new GCMParameterSpec(128, nonce);

  try {
    cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"), paramSpec);
    cipher.doFinal(data);
  } catch (InvalidKeyException e) {
    throw new InterledgerRuntimeException("Error loading 256bit key. "
        + "Likley cause is missing Unlimited Strength Jurisdiction Policy Files.", e);
  }

}
 

protected byte[] engineDoFinal(
    byte[]  input,
    int     inputOffset,
    int     inputLen) 
    throws IllegalBlockSizeException, BadPaddingException
{
    int     len = 0;
    byte[]  tmp = new byte[engineGetOutputSize(inputLen)];

    if (inputLen != 0)
    {
        len = cipher.processBytes(input, inputOffset, inputLen, tmp, 0);
    }

    try
    {
        len += cipher.doFinal(tmp, len);
    }
    catch (DataLengthException e)
    {
        throw new IllegalBlockSizeException(e.getMessage());
    }

    if (len == tmp.length)
    {
        return tmp;
    }

    byte[]  out = new byte[len];

    System.arraycopy(tmp, 0, out, 0, len);

    return out;
}
 

/**
 * Computes and returns the cleartext of the given ciphertext.
 *
 * @param ciphertext              The ciphertext to be decrypted.
 * @param algorithm               The encryption / decryption algorithm
 * @param javaSecurityAPIProvider
 * @return The cleartext
 * @throws CryptoException If something unexpected happens during the decryption operation.
 */
public byte[] decrypt(byte[] ciphertext, String algorithm, String javaSecurityAPIProvider) throws CryptoException {

    try {
        Cipher cipher;

        if (StringUtils.isBlank(javaSecurityAPIProvider)) {
            cipher = Cipher.getInstance(algorithm);
        } else {
            cipher = Cipher.getInstance(algorithm, javaSecurityAPIProvider);
        }

        cipher.init(Cipher.DECRYPT_MODE, getPrivateKeyFromKeyStore());

        if (log.isDebugEnabled()) {
            log.debug(String.format("Successfully decrypted data using the algorithm '%s' and the "
                                            + "Java Security API provider '%s'", algorithm,
                                    javaSecurityAPIProvider));
        }

        return cipher.doFinal(ciphertext);
    } catch (NoSuchAlgorithmException | NoSuchPaddingException | NoSuchProviderException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException | UnrecoverableKeyException | KeyStoreException e) {
        String errorMessage = String
                .format("An error occurred while decrypting using the algorithm : '%s'", algorithm);

        // Log the exception from client libraries, to avoid missing information if callers code doesn't log it
        if (log.isDebugEnabled()) {
            log.debug(errorMessage, e);
        }

        throw new CryptoException(errorMessage, e);
    }
}
 

protected byte[] encryptSymmetricKey(byte[] keyBytes,
                                     X509Certificate remoteCert,
                                     String keyEncAlgo,
                                     String digestAlgo) throws WSSecurityException {
    Cipher cipher =
        EncryptionUtils.initCipherWithCert(
            keyEncAlgo, digestAlgo, Cipher.ENCRYPT_MODE, remoteCert
        );
    int blockSize = cipher.getBlockSize();
    if (blockSize > 0 && blockSize < keyBytes.length) {
        String message = "Public key algorithm too weak to encrypt symmetric key";
        LOG.severe(message);
        throw new WSSecurityException(
            WSSecurityException.ErrorCode.FAILURE,
            "unsupportedKeyTransp",
            new Object[] {message}
        );
    }
    byte[] encryptedEphemeralKey = null;
    try {
        encryptedEphemeralKey = cipher.doFinal(keyBytes);
    } catch (IllegalStateException | IllegalBlockSizeException | BadPaddingException ex) {
        throw new WSSecurityException(WSSecurityException.ErrorCode.FAILED_ENCRYPTION, ex
        );
    }

    return encryptedEphemeralKey;

}
 

/** {@inheritDoc} */
@Override public byte[] encrypt(byte[] data) {
    if (data == null)
        throw new IgniteException("Parameter [data] cannot be null");

    if (encCipher == null)
        throw new IgniteException("The init() method was not called.");

    try {
        return encCipher.doFinal(data);
    }
    catch (IllegalBlockSizeException | BadPaddingException e) {
        throw new IgniteException(e);
    }
}
 

/**
 * The private key corresponding to the contract certificate is to be decrypted by 
 * the receiver (EVCC) using the session key derived in the ECDH protocol.
 * Applies the algorithm AES-CBC-128 according to NIST Special Publication 800-38A.
 * The initialization vector IV shall be read from the 16 most significant bytes of the 
 * ContractSignatureEncryptedPrivateKey field.
 * 
 * @param sessionKey The symmetric session key with which the encrypted private key is to be decrypted
 * @param encryptedKeyWithIV The encrypted private key of the contract certificate given as a byte array
 * 							 whose first 16 byte hold the initialization vector
 * @return The decrypted private key of the contract certificate
 */
private static ECPrivateKey decryptPrivateKey(SecretKey sessionKey, byte[] encryptedKeyWithIV) {
	byte[] initVector = new byte[16];
	byte[] encryptedKey = null;
	
	try {
		// Get the first 16 bytes of the encrypted private key which hold the IV
		
		encryptedKey = new byte[encryptedKeyWithIV.length - 16];
		System.arraycopy(encryptedKeyWithIV, 0, initVector, 0, 16);
		System.arraycopy(encryptedKeyWithIV, 16, encryptedKey, 0, encryptedKeyWithIV.length - 16);
		
		IvParameterSpec ivParamSpec = new IvParameterSpec(initVector);
		Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
		
		/*
		 * You must have the Java Cryptography Extension (JCE) Unlimited Strength 
		 * Jurisdiction Policy Files 8 installed, otherwise this cipher.init call will yield a
		 * "java.security.InvalidKeyException: Illegal key size"
		 */
		cipher.init(Cipher.DECRYPT_MODE, sessionKey, ivParamSpec);
		byte[] decrypted = cipher.doFinal(encryptedKey);

		return getPrivateKey(decrypted);
	} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException |
			InvalidAlgorithmParameterException | IllegalBlockSizeException | BadPaddingException |
			NegativeArraySizeException e) {
		getLogger().error(e.getClass().getSimpleName() + " occurred while trying to decrypt private key" +
				  "\nSession key (" + (sessionKey != null ? sessionKey.getEncoded().length : 0) + " bytes): " +
				  ByteUtils.toHexString(sessionKey.getEncoded()) +
				  "\nEncrypted key (" + (encryptedKey != null ? encryptedKey.length : 0) + " bytes): " +
				  ByteUtils.toHexString(encryptedKey) +
				  "\nEncrypted key with IV (" + (encryptedKeyWithIV != null ? encryptedKeyWithIV.length : 0) + " bytes): " +
				  ByteUtils.toHexString(encryptedKey), e);
	} 
	
	return null;
}
 

public void reset(InputStream in) throws IOException
{
    this.in = in;
    this.inBufPos = 16;
    this.end = false;
    try
    {
        this.cipher.doFinal(cipherBuf, 0, 0, inBuf);
    }
    catch (ShortBufferException | IllegalBlockSizeException | BadPaddingException e)
    {
        throw new IOException(e);
    }
}
 

public XmppAxolotlPlaintextMessage decrypt(XmppAxolotlSession session, Integer sourceDeviceId) throws CryptoFailedException {
    XmppAxolotlPlaintextMessage plaintextMessage = null;
    byte[] key = unpackKey(session, sourceDeviceId);
    if (key != null) {
        try {
            if (key.length < 32) {
                throw new OutdatedSenderException("Key did not contain auth tag. Sender needs to update their OMEMO client");
            }
            final int authTagLength = key.length - 16;
            byte[] newCipherText = new byte[key.length - 16 + ciphertext.length];
            byte[] newKey = new byte[16];
            System.arraycopy(ciphertext, 0, newCipherText, 0, ciphertext.length);
            System.arraycopy(key, 16, newCipherText, ciphertext.length, authTagLength);
            System.arraycopy(key, 0, newKey, 0, newKey.length);
            ciphertext = newCipherText;
            key = newKey;

            final Cipher cipher = Compatibility.twentyEight() ? Cipher.getInstance(CIPHERMODE) : Cipher.getInstance(CIPHERMODE, PROVIDER);
            SecretKeySpec keySpec = new SecretKeySpec(key, KEYTYPE);
            IvParameterSpec ivSpec = new IvParameterSpec(iv);

            cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);

            String plaintext = new String(cipher.doFinal(ciphertext));
            plaintextMessage = new XmppAxolotlPlaintextMessage(Config.OMEMO_PADDING ? plaintext.trim() : plaintext, session.getFingerprint());

        } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException
                | InvalidAlgorithmParameterException | IllegalBlockSizeException
                | BadPaddingException | NoSuchProviderException e) {
            throw new CryptoFailedException(e);
        }
    }
    return plaintextMessage;
}
 

static void cbc_readAllIllegalBlockSize() throws Exception {
    byte[] read = new byte[200];

    System.out.println("Running cbc_readAllIllegalBlockSize test");

    // Encrypt 96 byte with AES/CBC/PKCS5Padding
    byte[] ct = encryptedText("CBC", 96);
    // Create a stream with only 95 bytes of encrypted data
    CipherInputStream in = getStream("CBC", ct, 95);

    try {
        int s, size = 0;
        while ((s = in.read(read)) != -1) {
            size += s;
        }
        throw new RuntimeException("Fail: No IllegalBlockSizeException. " +
                "CipherInputStream.read() returned " + size);

    } catch (IOException e) {
        Throwable ec = e.getCause();
        if (ec instanceof IllegalBlockSizeException) {
            System.out.println("  Pass.");
        } else {
            System.out.println("  Fail: " + ec.getMessage());
            throw new RuntimeException(ec);
        }
    }
}
 

@Override
public String decrypt(String encryptedString) throws GeneralSecurityException {
    try {
        if (encryptedString != null && encryptedString.length() > 0) {
            if (mCipher == null) {
                throw new InvalidParameterException(
                        "Cipher is null. Please initialize proper cipher");
            }
            if (initCipher(mKeyAlias, Cipher.DECRYPT_MODE)) {
                StringBuilder decryptedBuilder = new StringBuilder();
                String[] chunks = encryptedString.split(CHUNK_SEPARATOR);
                for (String chunk : chunks) {
                    byte[] bytes = Base64.decode(chunk, Base64.NO_WRAP);
                    decryptedBuilder.append(new String(mCipher.doFinal(bytes)));
                }
                return decryptedBuilder.toString();
            }
        }
        return encryptedString;
    } catch (IllegalBlockSizeException e) {
        // We generate keys using UserAuthenticationValidityDurationSeconds parameter.
        // We decrypt data by chunk. This exception could be if this validity duration ended
        // during decryption. In this reason we check cause exception and provide valid
        // exception to user space
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M
                && e.getCause() instanceof UserNotAuthenticatedException) {
            throw new OktaUserNotAuthenticateException(
                    getUserNotAuthenticatedMessage(mCipher), e);
        }
        throw e;
    }
}