void
CryptoProxy::encrypt(CryptoKey* key, const ByteVector& data, ByteVector& encryptedData)
{
if ((data.length() % 16) > 0)
throw runtime_error("encrypt: incorrect data length");
encryptedData = data; //Crypto encrypts in-place
// NOTE: do not reserve block for padding, specify final = FALSE instead
//encryptedData.append(0x00, 16); // add one extra block as MS wants it for padding
const DWORD bytesToEncrypt = static_cast<DWORD>(data.size());
DWORD dataSize = bytesToEncrypt;
try
{
TOE(CryptEncrypt(*key, 0, FALSE/*final*/, 0/*flags*/, &encryptedData.front(),
&dataSize, static_cast<DWORD>(encryptedData.size())), "CryptEncrypt 1st");
}
catch (WinApiError& e)
{
// larger buffer is required??
if (e.getErr() == ERROR_MORE_DATA)
{
encryptedData.append(0x00, dataSize - encryptedData.size());
// try again, no second catch this time
dataSize = bytesToEncrypt; //set again to input data length
TOE(CryptEncrypt(*key, 0, FALSE/*final*/, 0/*flags*/, &encryptedData.front(),
&dataSize, static_cast<DWORD>(encryptedData.size())), "CryptEncrypt 2nd");
}
else
throw; // another error -> re-throw
}
// strip the padding
encryptedData.resize(bytesToEncrypt);
}
void
CryptoHash::getValue(ByteVector& value)
{
DWORD reqHashLen = 0;
TOE(CryptGetHashParam(handle, HP_HASHVAL, NULL, &reqHashLen, 0), "CryptGetHashParam");
value.resize(reqHashLen);
TOE(CryptGetHashParam(handle, HP_HASHVAL, &value.front(), &reqHashLen, 0), "CryptGetHashParam");
}
void
CryptoProxy::decrypt(CryptoKey* key, const ByteVector& data, ByteVector& decryptedData)
{
decryptedData = data; //Crypto decrypts in-place
DWORD dataSize = static_cast<DWORD>(data.size());
// NOTE: check FINAL again - currently no FINAL to avoid checking padding
//TOE(CryptDecrypt(*key, 0, TRUE, 0/*flags*/, &decryptedData.front(), &dataSize), "CryptDecrypt");
TOE(CryptDecrypt(*key, 0, FALSE, 0/*flags*/, &decryptedData.front(), &dataSize), "CryptDecrypt");
if (dataSize < decryptedData.size())
{
decryptedData.resize(decryptedData.size() - dataSize);
}
}
void
CryptoProxy::genRand(unsigned int reqSize, ByteVector& randData)
{
randData.resize(reqSize);
TOE(CryptGenRandom(impl->provider, reqSize, &randData.front()), "CryptGenRandom");
}
