AES CBC 128BIT PKCS5 암/복호화(C++)

Crypto++ 라이브러리를 이용함 암/복호화

(AES CBC 128BIT PKCS5)

#include "UtilsCrypto.h" //헤더는 별내용 없음
#include "cryptopp/cryptlib.h"
#include "cryptopp/modes.h"
#include "cryptopp/aes.h"
#include "cryptopp/filters.h"
#include "cryptopp/base64.h"
#include "cryptopp/md5.h"
#include "cryptopp/hex.h"

UtilsCrypto::UtilsCrypto(void)
{
}


UtilsCrypto::~UtilsCrypto(void)
{
}

void UtilsCrypto::hex2byte(const char *in, _UInt32 len, byte *out)
{
	for(_UInt32 i = 0; i < len; i+=2)
	{
		char c0 = in[i+0];
		char c1 = in[i+1];
		byte c = (
			((c0 & 0x40 ? (c0 & 0x20 ? c0 - 0x57 : c0 - 0x37) : c0 - 0x30) << 4) |
			((c1 & 0x40 ? (c1 & 0x20 ? c1 - 0x57 : c1 - 0x37) : c1 - 0x30))
		);
		out[i/2] = c;
	}
}

std::string UtilsCrypto::MD5HASH(std::string str)
{
	CryptoPP::MD5 hash;
	byte digest[CryptoPP::MD5::DIGESTSIZE];
	
	hash.CalculateDigest(digest, (byte*)str.c_str(), str.length());

	CryptoPP::HexEncoder encoder;
	std::string output;
	encoder.Attach(new CryptoPP::StringSink(output));
	encoder.Put(digest, sizeof(digest));
	encoder.MessageEnd();

	return output;
}

std::string UtilsCrypto::encrypt(std::string str)
{
	std::string enc_key = MD5HASH("암호키");
	std::string enc_iv = MD5HASH("iv키");

	//키할당
	byte key[CryptoPP::AES::DEFAULT_KEYLENGTH];
	memset(key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH);
	const char* rawKey = enc_key.c_str();
	hex2byte(rawKey, strlen(rawKey), key);

	//iv할당
	byte iv[CryptoPP::AES::BLOCKSIZE];
	memset(iv, 0x00, CryptoPP::AES::BLOCKSIZE);
	const char* rawIv = enc_iv.c_str();
	hex2byte(rawIv, strlen(rawIv), iv);

	std::string cipher, encoded;
	try
	{
		CryptoPP::CBC_Mode<CryptoPP::AES>::Encryption e;
		e.SetKeyWithIV(key, sizeof(key), iv);

		CryptoPP::StringSource ss(str, true, new CryptoPP::StreamTransformationFilter(e, new CryptoPP::StringSink(cipher), CryptoPP::BlockPaddingSchemeDef::PKCS_PADDING));
		CryptoPP::StringSource(cipher, true, new CryptoPP::Base64Encoder(new CryptoPP::StringSink(encoded), false)); //base64encoder 두번째 인자에 false를 줘야 마지막애 개행문자가 추가안됨

		return encoded;
	}
	catch(const CryptoPP::Exception& e)
	{
		std::cerr << e.what() << std::endl;
		return NULL;
	}
}

std::string UtilsCrypto::decrypt(std::string str)
{
	std::string enc_key = MD5HASH("암호키");
	std::string enc_iv = MD5HASH("iv키");

	//키할당
	byte key[CryptoPP::AES::DEFAULT_KEYLENGTH];
	memset(key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH);
	const char* rawKey = enc_key.c_str();
	hex2byte(rawKey, strlen(rawKey), key);

	//iv할당
	byte iv[CryptoPP::AES::BLOCKSIZE];
	memset(iv, 0x00, CryptoPP::AES::BLOCKSIZE);
	const char* rawIv = enc_iv.c_str();
	hex2byte(rawIv, strlen(rawIv), iv);

	std::string cipher, decoded;
	try
	{
		CryptoPP::CBC_Mode<CryptoPP::AES>::Decryption d;
		d.SetKeyWithIV(key, sizeof(key), iv);

		CryptoPP::StringSource(str, true, new CryptoPP::Base64Decoder(new CryptoPP::StringSink(cipher)));
		CryptoPP::StringSource ss(cipher, true, new CryptoPP::StreamTransformationFilter(d, new CryptoPP::StringSink(decoded), CryptoPP::BlockPaddingSchemeDef::PKCS_PADDING));

		return decoded;
	}
	catch(const CryptoPP::Exception& e)
	{
		std::cerr << e.what() << std::endl;
		return NULL;
	}
}