private static BigInteger FindE(BigInteger phi)
{
int[] staticE = new int[] { 3, 17, 65537 };
foreach (var e in staticE)
{
if (ExtendedEuclid(phi, e).d == 1)
{
return(e);
}
}
BigInteger generatedE = BigIntegerRandom.Generate(phi);
for (; ; generatedE++)
{
if (ExtendedEuclid(phi, generatedE).d == 1)
{
return(generatedE);
}
}
}
public static bool IsPrime(BigInteger n, BigInteger k)
{
if (n <= 1)
{
return(false);
}
if (n <= 3)
{
return(true);
}
if (n % 2 == 0)
{
return(false);
}
BigInteger s = BigInteger.One;
BigInteger t = (n - 1) / two;
while (t % 2 == BigInteger.Zero)
{
t = BigInteger.Divide(t, two);
s++;
}
for (BigInteger i = BigInteger.Zero; i < k; i++)
{
BigInteger a = BigInteger.Add(two, BigIntegerRandom.Generate(n - 4));
var u = BigInteger.ModPow(a, t, n);
if (u == 1 || u == n - 1)
{
continue;
}
var j = BigInteger.Zero;
bool isNotPrime = false;
while (j < s)
{
u = BigInteger.ModPow(u, two, n);
j++;
if (u.IsOne)
{
return(false);
}
if (u == n - 1)
{
isNotPrime = true;
break;
}
}
if (isNotPrime)
{
continue;
}
return(false);
}
return(true);
}