void CRegProtocol::GenerateSHA256Hash(BufferObj &inBuf, BufferObj &outBuf)
{
uint8 Hash[SIZE_256_BITS];
if(SHA256(inBuf.GetBuf(), inBuf.Length(), Hash) == NULL)
{
TUTRACE((TUTRACE_ERR, "RPROTO: SHA256 calculation failed\n"));
throw RPROT_ERR_CRYPTO;
}
outBuf.Append(SIZE_256_BITS, Hash);
}//GenerateHash
void CRegProtocol::DeriveKey(BufferObj &KDK,
BufferObj &prsnlString,
uint32 keyBits,
BufferObj &key)
{
uint32 i = 0, iterations = 0;
BufferObj input, output;
uint8 hmac[SIZE_256_BITS];
uint32 hmacLen = 0;
uint8 *inPtr;
uint32 temp;
TUTRACE((TUTRACE_INFO, "RPROTO: Deriving a key of %d bits\n", keyBits));
iterations = ((keyBits/8) + PRF_DIGEST_SIZE - 1)/PRF_DIGEST_SIZE;
//Prepare the input buffer. During the iterations, we need only replace the
//value of i at the start of the buffer.
temp = WscHtonl(i);
input.Append(SIZE_4_BYTES, (uint8 *)&temp);
input.Append(prsnlString.Length(), prsnlString.GetBuf());
temp = WscHtonl(keyBits);
input.Append(SIZE_4_BYTES, (uint8 *)&temp);
inPtr = input.GetBuf();
for(i = 0; i < iterations; i++)
{
//Set the current value of i at the start of the input buffer
*(uint32 *)inPtr = WscHtonl(i+1); //i should start at 1
if(HMAC(EVP_sha256(), KDK.GetBuf(), SIZE_256_BITS, input.GetBuf(),
input.Length(), hmac, &hmacLen) == NULL)
{
TUTRACE((TUTRACE_ERR, "RPROTO: HMAC failed\n"));
throw RPROT_ERR_CRYPTO;
}
output.Append(hmacLen, hmac);
}
//Sanity check
if(keyBits/8 > output.Length())
{
TUTRACE((TUTRACE_ERR, "RPROTO: Key derivation generated less bits "
"than asked\n"));
throw RPROT_ERR_CRYPTO;
}
//We now have at least the number of key bits requested.
//Return only the number of bits asked for. Discard the excess.
key.Append(keyBits/8, output.GetBuf());
}
void
CRegProtocol::DecryptData(BufferObj &cipherText,
BufferObj &iv,
BufferObj &encrKey,
BufferObj &authKey,
BufferObj &plainText)
{
EVP_CIPHER_CTX ctx;
if(0 == EVP_DecryptInit(&ctx, EVP_aes_128_cbc(), encrKey.GetBuf(), iv.GetBuf()))
{
TUTRACE((TUTRACE_ERR, "RPROTO: DecryptInit failed\n"));
throw RPROT_ERR_CRYPTO;
}
BufferObj buf;
int bufLen = 1024;
uint8 outBuf[1024];
int outLen, currentLength;
//block size = 1024 bytes - 128 bits,
//leave 128 bits at the end to accommodate any possible padding
//and avoid a buffer overflow
int blockSize = bufLen - SIZE_128_BITS;
int length = cipherText.Length();
uint8 *bufPtr = cipherText.GetBuf();
while(length)
{
if(length > blockSize)
currentLength = blockSize;
else
currentLength = length;
if(0 == EVP_DecryptUpdate(&ctx, outBuf, &outLen, bufPtr, currentLength))
{
TUTRACE((TUTRACE_ERR, "RPROTO: DecryptUpdate failed\n"));
throw RPROT_ERR_CRYPTO;
}
buf.Append(outLen, outBuf);
bufPtr += currentLength;
length -= currentLength;
}
if(0 == EVP_DecryptFinal(&ctx, outBuf, &outLen))
{
TUTRACE((TUTRACE_ERR, "RPROTO: DecryptFinal failed\n"));
throw RPROT_ERR_CRYPTO;
}
buf.Append(outLen, outBuf);
//Validate the mac at the end of the decrypted buffer
//uint8 *mac = buf.GetBuf()+(buf.Length()-SIZE_256_BITS);//get the last 256 bits
//if(0 == ValidateMac(BufferObj(buf.GetBuf(), buf.Length()-SIZE_256_BITS), mac, authKey))
//{
// TUTRACE((TUTRACE_ERR, "RPROTO: Mac validation failed\n"));
// throw RPROT_ERR_INVALID_VALUE;
//}
//plainText.Append(buf.Length()-SIZE_256_BITS, buf.GetBuf());
plainText.Append(buf.Length(), buf.GetBuf());
plainText.Rewind(plainText.Length());
}
void
CRegProtocol::EncryptData(BufferObj &plainText,
BufferObj &encrKey,
BufferObj &authKey,
BufferObj &cipherText,
BufferObj &iv)
{
BufferObj buf;
uint8 ivBuf[SIZE_128_BITS];
if(0 == plainText.Length())
throw WSC_ERR_INVALID_PARAMETERS;
//Generate a random iv
RAND_bytes(ivBuf, SIZE_128_BITS);
iv.Reset();
iv.Append(SIZE_128_BITS, ivBuf);
//Now encrypt the plaintext and mac using the encryption key and IV.
buf.Append(plainText.Length(), plainText.GetBuf());
EVP_CIPHER_CTX ctx;
if(0 == EVP_EncryptInit(&ctx, EVP_aes_128_cbc(), encrKey.GetBuf(), ivBuf))
{
TUTRACE((TUTRACE_ERR, "RPROTO: EncryptInit failed\n"));
throw RPROT_ERR_CRYPTO;
}
int bufLen = 1024;
uint8 outBuf[1024];
int outLen, currentLength;
//block size = 1024 bytes - 128 bits,
//leave 128 bits at the end to accommodate any possible padding
//and avoid a buffer overflow
int blockSize = bufLen - SIZE_128_BITS;
int length = buf.Length();
uint8 *bufPtr = buf.GetBuf();
while(length)
{
if(length > blockSize)
currentLength = blockSize;
else
currentLength = length;
if(0 == EVP_EncryptUpdate(&ctx, outBuf, &outLen, bufPtr, currentLength))
{
TUTRACE((TUTRACE_ERR, "RPROTO: EncryptUpdate failed\n"));
throw RPROT_ERR_CRYPTO;
}
cipherText.Append(outLen, outBuf);
bufPtr += currentLength;
length -= currentLength;
}
if(0 == EVP_EncryptFinal(&ctx, outBuf, &outLen))
{
TUTRACE((TUTRACE_ERR, "RPROTO: EncryptFinal failed\n"));
throw RPROT_ERR_CRYPTO;
}
cipherText.Append(outLen, outBuf);
}
uint32 CRegProtocol::GenerateDHKeyPair(DH **DHKeyPair, BufferObj &pubKey)
{
uint8 temp[SIZE_PUB_KEY];
try
{
//1. Initialize the DH structure
*DHKeyPair = DH_new();
if(*DHKeyPair == NULL)
{
TUTRACE((TUTRACE_ERR, "RPROTO: DH_new failed\n"));
throw RPROT_ERR_CRYPTO;
}
(*DHKeyPair)->p = BN_new();
(*DHKeyPair)->g = BN_new();
//2. load the value of P
if(BN_bin2bn(DH_P_VALUE,
BUF_SIZE_1536_BITS,
(*DHKeyPair)->p)==NULL)
{
TUTRACE((TUTRACE_ERR, "RPROTO: BN_bin2bn P: %s",
ERR_error_string(ERR_get_error(), NULL)));
throw RPROT_ERR_CRYPTO;
}
//3. load the value of G
uint32 g = WscHtonl(DH_G_VALUE);
if(BN_bin2bn((uint8 *)&g,
4,
(*DHKeyPair)->g)==NULL)
{
TUTRACE((TUTRACE_ERR, "RPROTO: BN_bin2bn G: %s",
ERR_error_string(ERR_get_error(), NULL)));
throw RPROT_ERR_CRYPTO;
}
//4. generate the DH key
if(DH_generate_key(*DHKeyPair) == 0)
{
TUTRACE((TUTRACE_ERR, "RPROTO: DH_generate_key: %s",
ERR_error_string(ERR_get_error(), NULL)));
throw RPROT_ERR_CRYPTO;
}
//5. extract the DH public key
int len = BN_bn2bin((*DHKeyPair)->pub_key, temp);
if(0 == len)
{
TUTRACE((TUTRACE_ERR, "RPROTO: BN_bn2bin: %s",
ERR_error_string(ERR_get_error(), NULL)));
throw RPROT_ERR_CRYPTO;
}
pubKey.Append(SIZE_PUB_KEY, temp);
return WSC_SUCCESS;
}
catch(uint32 err)
{
return err;
}
catch(...)
{
return WSC_ERR_SYSTEM;
}
}//GenerateDHKeyPair
