Get hexadecimal encrypted string in AES 256 Crypto++

Question

I am trying to implement the AES 256 algorithm using Crypto++ in MS visual studio. Operating system is Windows 7 (64 bit).

I need to provide the key as a hexadecimal string, password as string and finally i want the encrypted string to also be hexadecimal string.

Here is what I am trying to do:

My encrypt method:

std::string encrypt(const std::string &password)
{
    std::string plain = password;
    std::string ciphertext;
    char * decodedKey= "729308A8E815F6A46EB3A8AE6D5463CA7B64A0E2E11BC26A68106FC7697E727E37011";

    byte key[ CryptoPP::AES::MAX_KEYLENGTH ], iv[ CryptoPP::AES::BLOCKSIZE ];
    CryptoPP::StringSource( reinterpret_cast<const char *>(decodedKey), true,
              new  CryptoPP::HashFilter(*(new  CryptoPP::SHA256), new CryptoPP::ArraySink(key, CryptoPP::AES::MAX_KEYLENGTH)) );
    memset( iv, 0x00,  CryptoPP::AES::BLOCKSIZE );

    CryptoPP::CBC_Mode<CryptoPP::AES>::Encryption Encryptor( key, sizeof(key), iv );
    CryptoPP::StringSource( plain, true, new CryptoPP::StreamTransformationFilter( Encryptor,
              new CryptoPP::HexEncoder(new CryptoPP::StringSink( ciphertext ) ) ) );

    std::cout<<"Ciphertext:" << ciphertext;
    return ciphertext;
}

From main method

int main(int argc, char* argv[]) {

    encrypt("test");
    return 0;
}

At present I am hardcoding the key just for debugging purposes. My key is hexadecimal string as seen below. I need to get the output encrypted string as hex string.

Answer 1

I need to provide the key as a hexadecimal string, password as string and finally i want the encrypted string to also be hexadecimal string.

This is covered in the Crypto++ wiki (there's lots of examples in there ready for copy/paste). From HexDecoder's Scripting and Strings:

On occasion, the mailing list will receive questions on cross-validation. For example, see AES CTR Chiper. Different output between PHP-mcrypt and Crypto++. In the question, PHP-mcrypt strings are used as follows:

$key = "1234567890123456789012345678901234567890123456789012345678901234";
$key = pack("H".strlen($key), $key);
$iv = "1111111111222222222233333333334444444444555555555566666666667777";
$iv = pack("H".strlen($iv), $iv);

One of the easiest ways to avoid typos is via Copy/Paste and a HexDecoder:

string encodedKey = "1234567890123456789012345678901234567890123456789012345678901234";
string encodedIv = "1111111111222222222233333333334444444444555555555566666666667777";
string key, iv;

StringSource ssk(encodedKey, true /*pumpAll*/,
    new HexDecoder(
        new StringSink(key)
    ) // HexDecoder
); // StringSource

StringSource ssv(encodedIv, true /*pumpAll*/,
    new HexDecoder(
        new StringSink(iv)
    ) // HexDecoder
); // StringSource

After running the above code, key and iv are hexadecimal (i.e., binary) strings rather than printable (i.e., ASCII) strings.