public EncryptedPacket EncryptData(byte[] original)
{
var sessionKey = aesEncryption.GenerateRandomNumber(32);
var encryptedPacket = new EncryptedPacket() { Iv = aesEncryption.GenerateRandomNumber(16) };
encryptedPacket.EncryptedData = aesEncryption.EncryptAes(original, sessionKey, encryptedPacket.Iv);
encryptedPacket.EncryptedSessionKey = asymmetricEncryption.EncryptData(sessionKey);
using (var hmac = new HMACSHA256(sessionKey))
{
encryptedPacket.Hmac = hmac.ComputeHash(encryptedPacket.EncryptedData);
}
return encryptedPacket;
}
public byte[] DecryptData(EncryptedPacket encryptedPacket)
{
var decryptedSessionKey = asymmetricEncryption.DecryptData(encryptedPacket.EncryptedSessionKey);
using (var hmac = new HMACSHA256(decryptedSessionKey))
{
var hmacToCheck = hmac.ComputeHash(encryptedPacket.EncryptedData);
if (!Compare(encryptedPacket.Hmac, hmacToCheck))
{
throw new CryptographicException("HMAC comparison failed");
}
}
var decryptedData = aesEncryption.DecryptAes(encryptedPacket.EncryptedData, decryptedSessionKey,
encryptedPacket.Iv);
return decryptedData;
}
