question: public static long decryptECB ( final byte [ ] concatenatedHashValue , final String base64EncryptedTurnOverValue , final SecretKey symmetricKey ) throws NoSuchAlgorithmException , NoSuchProviderException , NoSuchPaddingException , InvalidKeyException , InvalidAlgorithmParameterException , IllegalBlockSizeException , BadPaddingException { final ByteBuffer byteBufferIV = ByteBuffer . allocate ( 16 ) ; byteBufferIV . put ( concatenatedHashValue ) ; final byte [ ] IV = byteBufferIV . array ( ) ; final byte [ ] encryptedTurnOverValue = CashBoxUtils . base64Decode ( base64EncryptedTurnOverValue , false ) ; final Cipher cipher = Cipher . getInstance ( "AES/ECB/NoPadding" , "BC" ) ; cipher . init ( Cipher . ENCRYPT_MODE , symmetricKey ) ; final byte [ ] intermediateResult = cipher . doFinal ( IV ) ; final byte [ ] result = new byte [ encryptedTurnOverValue . length ] ; for ( int i = 0 ; i < encryptedTurnOverValue . length ; i ++ ) { result [ i ] = ( byte ) ( ( encryptedTurnOverValue [ i ] ) ^ ( intermediateResult [ i ] ) ) ; } return getLong ( result ) ; }
target:  method for AES decryption in ECB mode