static void Main()
{
const string original = "abcdefghijklmnopqrstvwxyz 123456789 !#@&|";
var hybrid = new HybridEncryption();
var rsaParams = new RSAWithRSAParameterKey();
rsaParams.AssignNewKey();
Console.WriteLine("Hybrid Encryption with Integrity Check Demonstration in .NET");
Console.WriteLine("------------------------------------------------------------");
Console.WriteLine();
try
{
var encryptedBlock = hybrid.EncryptData(Encoding.UTF8.GetBytes(original), rsaParams);
var decrpyted = hybrid.DecryptData(encryptedBlock, rsaParams);
Console.WriteLine("Original Message = " + original);
Console.WriteLine();
Console.WriteLine("Message After Decryption = " + Encoding.UTF8.GetString(decrpyted));
}
catch (CryptographicException ex)
{
Console.WriteLine("Error : " + ex.Message);
}
Console.ReadLine();
}
static void Main()
{
const string original = "Very secret and important information that can not fall into the wrong hands.";
var hybrid = new HybridEncryption();
var rsaParams = new RSAWithRSAParameterKey();
rsaParams.AssignNewKey();
var digitalSignature = new DigitalSignature();
digitalSignature.AssignNewKey();
Console.WriteLine();
try
{
var encryptedBlock = hybrid.EncryptData(Encoding.UTF8.GetBytes(original), rsaParams,
digitalSignature);
var decrpyted = hybrid.DecryptData(encryptedBlock, rsaParams, digitalSignature);
Console.WriteLine("Original Message = " + original);
Console.WriteLine();
Console.WriteLine("Message After Decryption = " + Encoding.UTF8.GetString(decrpyted));
}
catch (CryptographicException ex)
{
Console.WriteLine("Error : " + ex.Message);
}
Console.ReadLine();
}
public byte[] DecryptData(EncryptedPacket encryptedPacket, RSAWithRSAParameterKey rsaParams,
DigitalSignature digitalSignature)
{
var decryptedSessionKey = rsaParams.DecryptData(encryptedPacket.EncryptedSessionKey);
using (var hmac = new HMACSHA256(decryptedSessionKey))
{
var hmacToCheck = hmac.ComputeHash(encryptedPacket.EncryptedData);
if (!Compare(encryptedPacket.Hmac, hmacToCheck)){
throw new CryptographicException(
"HMAC for decryption does not match encrypted packet.");
}
if (!digitalSignature.VerifySignature(encryptedPacket.Hmac,
encryptedPacket.Signature)){
throw new CryptographicException(
"Digital Signature can not be verified.");
}
}
var decryptedData = _aes.Decrypt(encryptedPacket.EncryptedData, decryptedSessionKey,
encryptedPacket.Iv);
return decryptedData;
}
public EncryptedPacket EncryptData(byte[] original, RSAWithRSAParameterKey rsaParams)
{
var sessionKey = _aes.GenerateRandomNumber(32);
var encryptedPacket = new EncryptedPacket {
Iv = _aes.GenerateRandomNumber(16)
};
// Encrypt data with AES and AES Key with RSA
encryptedPacket.EncryptedData = _aes.Encrypt(original, sessionKey, encryptedPacket.Iv);
encryptedPacket.EncryptedSessionKey = rsaParams.EncryptData(sessionKey);
using (var hmac = new HMACSHA256(sessionKey))
{
encryptedPacket.Hmac = hmac.ComputeHash(encryptedPacket.EncryptedData);
}
return(encryptedPacket);
}
public byte[] DecryptData(EncryptedPacket encryptedPacket, RSAWithRSAParameterKey rsaParams)
{
// Decrypt AES Key with RSA and then decrypt data with AES.
var decryptedSessionKey = rsaParams.DecryptData(encryptedPacket.EncryptedSessionKey);
using (var hmac = new HMACSHA256(decryptedSessionKey))
{
var hmacToCheck = hmac.ComputeHash(encryptedPacket.EncryptedData);
if (!Compare(encryptedPacket.Hmac, hmacToCheck))
{
throw new CryptographicException("HMAC for decryption does not match encrypted packet.");
}
}
var decryptedData = _aes.Decrypt(encryptedPacket.EncryptedData, decryptedSessionKey, encryptedPacket.Iv);
return(decryptedData);
}
public EncryptedPacket EncryptData(byte[] original, RSAWithRSAParameterKey rsaParams,
DigitalSignature digitalSignature)
{
var sessionKey = _aes.GenerateRandomNumber(32);
var encryptedPacket = new EncryptedPacket { Iv = _aes.GenerateRandomNumber(16) };
encryptedPacket.EncryptedData = _aes.Encrypt(original, sessionKey, encryptedPacket.Iv);
encryptedPacket.EncryptedSessionKey = rsaParams.EncryptData(sessionKey);
using (var hmac = new HMACSHA256(sessionKey))
{
encryptedPacket.Hmac = hmac.ComputeHash(encryptedPacket.EncryptedData);
}
encryptedPacket.Signature = digitalSignature.SignData(encryptedPacket.Hmac);
return encryptedPacket;
}
private static void RsaWithRsaParameterKey()
{
var rsaParams = new RSAWithRSAParameterKey();
const string original = "Text to encrypt";
rsaParams.AssignNewKey();
var encryptedRsaParams = rsaParams.EncryptData(Encoding.UTF8.GetBytes(original));
var decryptedRsaParams = rsaParams.DecryptData(encryptedRsaParams);
Console.WriteLine();
Console.WriteLine("In Memory Key");
Console.WriteLine();
Console.WriteLine(" Original Text = " + original);
Console.WriteLine();
Console.WriteLine(" Encrypted Text = " + Convert.ToBase64String(encryptedRsaParams));
Console.WriteLine();
Console.WriteLine(" Decrypted Text = " + Encoding.Default.GetString(decryptedRsaParams));
Console.WriteLine();
Console.WriteLine();
}