public string Encrypt(string plainText, RSAPublicKey publicKey)
{
byte[] plainTextAsBytes = Encoding.UTF8.GetBytes(plainText);
BigInteger plainTextAsNumber = new BigInteger(plainTextAsBytes);
if (plainTextAsNumber > publicKey.N)
{
// Chunking is not suported since it was implemented already in Assignment 3.
throw new Exception("The Master Key cannot exceed n");
}
BigInteger cipherTextAsBigInteger = Helpers.SquareAndMultiply(plainTextAsNumber, publicKey.E, publicKey.N);
byte[] cipherTextAsBytes = cipherTextAsBigInteger.ToByteArray();
string cipherText = Convert.ToBase64String(cipherTextAsBytes);
return(cipherText);
}
public void RunTest()
{
int desiredBitSize = 32;
BigInteger p;
BigInteger q;
BigInteger n = GenerateN(desiredBitSize, out p, out q);
BigInteger phi = (p - 1) * (q - 1);
BigInteger e = GenerateE(phi);
BigInteger d = Helpers.MultiplicativeInverse(e, phi);
RSAPublicKey publicKey = new RSAPublicKey(n, e);
// PUBLIC KEY RECEIVED. ENCRYPT SOMETHING.
int message = 4;
BigInteger cipherText = Helpers.SquareAndMultiply(message, e, n);
Console.WriteLine("cipherText: " + cipherText);
BigInteger plainText = Helpers.SquareAndMultiply(cipherText, d, n);
Console.WriteLine("plainText: " + plainText);
}
public BigInteger Encrypt(BigInteger plainTextAsBigInteger, RSAPublicKey publicKey)
{
BigInteger cipherTextAsBigInteger = Helpers.SquareAndMultiply(plainTextAsBigInteger, publicKey.E, publicKey.N);
return(cipherTextAsBigInteger);
}
