public byte[] OaepEncrypt(byte[] data, TpmAlgId hashAlg, byte[] encodingParms)
{
int encLen = NumBits / 8;
byte[] zeroTermEncoding = GetLabel(encodingParms);
byte[] encoded = CryptoEncoders.OaepEncode(data, zeroTermEncoding, hashAlg, encLen);
BigInteger message = FromBigEndian(encoded);
BigInteger cipher = BigInteger.ModPow(message, E, N);
byte[] encMessageBigEnd = ToBigEndian(cipher, KeySize);
if (encMessageBigEnd.Length < encLen)
{
encMessageBigEnd = Globs.AddZeroToBeginning(encMessageBigEnd, encLen - encMessageBigEnd.Length);
}
return(encMessageBigEnd);
}
public byte[] OaepDecrypt(byte[] cipherText, TpmAlgId hashAlg, byte[] encodingParms)
{
byte[] zeroTermEncoding = GetLabel(encodingParms);
BigInteger cipher = FromBigEndian(cipherText);
BigInteger plain = BigInteger.ModPow(cipher, D, N);
byte[] encMessage = ToBigEndian(plain, KeySize - 1);
byte[] message;
// Hack - be robust to leading zeros
while (true)
{
bool decodeOk = CryptoEncoders.OaepDecode(encMessage, zeroTermEncoding, hashAlg, out message);
if (decodeOk)
{
break;
}
encMessage = Globs.AddZeroToBeginning(encMessage);
}
return(message);
}
