question: public static long decryptCTR ( 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 IvParameterSpec ivSpec = new IvParameterSpec ( IV ) ; final Cipher cipher = Cipher . getInstance ( "AES/CTR/NoPadding" , "BC" ) ; cipher . init ( Cipher . DECRYPT_MODE , symmetricKey , ivSpec ) ; final byte [ ] testPlainTurnOverValueComplete = cipher . doFinal ( encryptedTurnOverValue ) ; return getLong ( testPlainTurnOverValueComplete ) ; }
target:  method for AES decryption in CTR mode