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();
}
static void Main()
{
var document = Encoding.UTF8.GetBytes("Document to Sign");
byte[] hashedDocument;
using (var sha256 = SHA256.Create())
{
hashedDocument = sha256.ComputeHash(document);
}
var digitalSignature = new DigitalSignature();
digitalSignature.AssignNewKey();
var signature = digitalSignature.SignData(hashedDocument);
var verified = digitalSignature.VerifySignature(hashedDocument, signature);
Console.WriteLine();
Console.WriteLine(" Original Text = " +
Encoding.Default.GetString(document));
Console.WriteLine();
Console.WriteLine(" Digital Signature = " +
Convert.ToBase64String(signature));
Console.WriteLine();
Console.WriteLine(verified
? "The digital signature has been correctly verified."
: "The digital signature has NOT been correctly verified.");
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,
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;
}
