core/src/main/java/com/orientechnologies/orient/core/security/symmetrickey/OSymmetricKey.java
public String encrypt(final String transform, final byte[] bytes) {
    String encodedJSON = null;

    if (secretKey == null)
      throw new OSecurityException("OSymmetricKey.encrypt() SecretKey is null");
    if (transform == null)
      throw new OSecurityException("OSymmetricKey.encrypt() Cannot determine cipher transformation");

    try {
      // Throws NoSuchAlgorithmException and NoSuchPaddingException.
      Cipher cipher = Cipher.getInstance(transform);

      // If the cipher transformation requires an initialization vector then init() will create a random one.
      // (Use cipher.getIV() to retrieve the IV, if it exists.)
      cipher.init(Cipher.ENCRYPT_MODE, secretKey);

      // If the cipher does not use an IV, this will be null.
      byte[] initVector = cipher.getIV();

//      byte[] initVector = encCipher.getParameters().getParameterSpec(IvParameterSpec.class).getIV();

      byte[] encrypted = cipher.doFinal(bytes);

      encodedJSON = encodeJSON(encrypted, initVector);
    } catch (Exception ex) {
      throw OException.wrapException(new OSecurityException("OSymmetricKey.encrypt() Exception: " + ex.getMessage()), ex);
    }

    return encodedJSON;
  }
public String encrypt(final String transform, final byte[] bytes) {
    String encodedJSON = null;

    if (secretKey == null)
      throw new OSecurityException("OSymmetricKey.encrypt() SecretKey is null");
    if (transform == null)
      throw new OSecurityException("OSymmetricKey.encrypt() Cannot determine cipher transformation");

    try {
      // Throws NoSuchAlgorithmException and NoSuchPaddingException.
      Cipher cipher = Cipher.getInstance(transform);

      // If the cipher transformation requires an initialization vector then init() will create a random one.
      // (Use cipher.getIV() to retrieve the IV, if it exists.)
      cipher.init(Cipher.ENCRYPT_MODE, secretKey);

      // If the cipher does not use an IV, this will be null.
      byte[] initVector = cipher.getIV();

//      byte[] initVector = encCipher.getParameters().getParameterSpec(IvParameterSpec.class).getIV();

      byte[] encrypted = cipher.doFinal(bytes);

      encodedJSON = encodeJSON(encrypted, initVector);
    } catch (Exception ex) {
      throw OException.wrapException(new OSecurityException("OSymmetricKey.encrypt() Exception: " + ex.getMessage()), ex);
    }

    return encodedJSON;
  }
This method encrypts an array of bytes.

@param transform The cipher transformation to use.
@param bytes     The array of bytes to be encrypted.

@return The encrypted bytes as a Base64-encoded JSON document or null if unsuccessful.