public byte[] DecryptData(EncryptedPacket encryptedpacket, RSAWithRSAParameterKey rsaParams)
{
// Decrypt AES Key with RSA
var decryptedSessionKey = rsaParams.DecryptData(encryptedpacket.EncryptedSessionKey);
// Decrypt our data with AES using the decrypted session key
var decryptedData = _aes.Decrypt(encryptedpacket.EncryptedData,
decryptedSessionKey, encryptedpacket.Iv);
return(decryptedData);
}
public static void EncryptDecryptWithAES()
{
var des = new AESEncryption();
var key = des.GenerateRandomNumber(32);
var iv = des.GenerateRandomNumber(16);
const string original = "Text to encrypt";
var encrypted = des.Encrypt(Encoding.UTF8.GetBytes(original), key, iv);
var decrypted = des.Decrypt(encrypted, key, iv);
var decryptedMessage = Encoding.UTF8.GetString(decrypted);
Console.WriteLine("AES Encryption Demonstration in .NET");
Console.WriteLine("------------------------------------");
Console.WriteLine();
Console.WriteLine("Original Text = " + original);
Console.WriteLine("Encrypted Text = " + Convert.ToBase64String(encrypted));
Console.WriteLine("Decrypted Text = " + decryptedMessage);
}
public byte[] DecryptData(EncryptedPacketIntegrityCheck encryptedpacket, RSAWithRSAParameterKey rsaParams)
{
// Decrypt AES Key with RSA
var decryptedSessionKey = rsaParams.DecryptData(encryptedpacket.EncryptedSessionKey);
using (var hmac = new HMACSHA256(decryptedSessionKey))
{
var hmacToCheck = hmac.ComputeHash(encryptedpacket.EncryptedData);
if (!Comparer(encryptedpacket.Hmac, hmacToCheck))
{
throw new CryptographicException("HMAC for decryption does not match");
}
}
// Decrypt our data with AES using the decrypted session key
var decryptedData = _aes.Decrypt(encryptedpacket.EncryptedData,
decryptedSessionKey, encryptedpacket.Iv);
return(decryptedData);
}