private BigInteger GeneratePrimeNumber()
{
BigInteger number = random.Next(1000, 5000);
while (!GCD.IsSimple(number))
{
number = random.Next(1000, 5000);
}
return(number);
}
public string Decrypt(BigInteger[,] encryptedText)
{
byte[] decryptedText = new byte[encryptedText.GetUpperBound(0) + 1];
for (int i = 0; i < encryptedText.GetUpperBound(0) + 1; i++)
{
BigInteger inverseA = GCD.ModInverse(BigInteger.Pow(encryptedText[i, 0], (int)x), p);
decryptedText[i] = Convert.ToByte(BigInteger.ModPow(BigInteger.Multiply(encryptedText[i, 1], inverseA), 1, p).ToString());
}
return(Encoding.ASCII.GetString(decryptedText));
}
private BigInteger GenerateCoprimeNumber(BigInteger coprime)
{
BigInteger number = random.Next(2, (int)coprime - 1), nod = GCD.GetNOD(number, coprime);
while (nod != 1)
{
number = random.Next(2, (int)coprime - 1);
nod = GCD.GetNOD(number, coprime);
}
return(number);
}
public RSA()
{
p = GeneratePrimeNumber();
q = GeneratePrimeNumber();
n = p * q;
fi = (p - 1) * (q - 1);
e = GenerateCoprimeNumber(fi);
d = GCD.ModInverse(e, fi);
Console.WriteLine(new string('-', 40) + "RSA" + new string('-', 40));
Console.WriteLine($"p = {p}, q = {q}, n = p * q = {p * q}, fi(n) = {fi}, e = {e}, d = {d}\n");
Console.WriteLine($"PUBLIC KEY: (e, n) = ({e}, {n})");
Console.WriteLine($"PRIVATE KEY: (d, n) = ({d}, {n})");
Console.WriteLine();
}