public Principal(string name, int generator, int modulus)
{
Console.WriteLine($"Creating principal {name}...");
Name = name;
Generator = generator;
Modulus = modulus;
_secret = PrimeGenerator.GetPrime();
SecretMessage = SquareAndMultiply.Calculate(Generator, _secret, Modulus);
Console.WriteLine($"{Name} has selected a secret: {_secret}");
Console.WriteLine($"{Name} calculated its secret message ({Generator}^{_secret}) mod {modulus}: {SecretMessage}");
rsa = new RSACryptoServiceProvider(2048);
_publicKey = rsa.ExportParameters(false);
_privateKey = rsa.ExportParameters(true);
Console.WriteLine($"{Name} created 2048 bit RSA public and private keys");
RSAPublicKeyStore.AddPublicKey(Name, _publicKey);
_secretMessages = new Dictionary <string, int>();
_symmetricKeys = new Dictionary <string, string>();
_authorizedPrincipals = new HashSet <string>();
Console.WriteLine($"Principal {Name} has been created successfully.\r\n");
}
private bool VerifyEncryptedMessage(string principalName, string encryptedMessage)
{
Console.WriteLine($"{Name} is decrypting and verifying the encrypted message...");
RSACryptoServiceProvider rsaVerify = new RSACryptoServiceProvider();
rsaVerify.ImportParameters(RSAPublicKeyStore.GetPublicKey(principalName));
string message = (((long)_secretMessages[principalName] << 32) | SecretMessage).ToString();
byte[] messageBytes = Encoding.Unicode.GetBytes(message);
string decryptedMessage = Encryption.Decrypt(encryptedMessage, _symmetricKeys[principalName]);
byte[] decryptedMessageBytes = Convert.FromBase64String(decryptedMessage);
bool isVerified = rsaVerify.VerifyData(messageBytes, CryptoConfig.MapNameToOID("SHA512"), decryptedMessageBytes);
Console.WriteLine($"{Name}, decrypted message: {decryptedMessage}");
Console.WriteLine($"{Name}, verifying decrpyted message with {principalName}'s public key...");
if (isVerified)
{
Console.WriteLine($"{Name}, verification is successfull.");
}
else
{
Console.WriteLine($"{Name}, encrypted message cannot be verified!");
}
return(isVerified);
}