private static STOutput ImplSTRandomPrime(IDigest d, int length, byte[] primeSeed)
{
int dLen = d.GetDigestSize();
if (length < 33)
{
int primeGenCounter = 0;
byte[] c0 = new byte[dLen];
byte[] c1 = new byte[dLen];
for (;;)
{
Hash(d, primeSeed, c0, 0);
Inc(primeSeed, 1);
Hash(d, primeSeed, c1, 0);
Inc(primeSeed, 1);
uint c = Extract32(c0) ^ Extract32(c1);
c &= (uint.MaxValue >> (32 - length));
c |= (1U << (length - 1)) | 1U;
++primeGenCounter;
if (IsPrime32(c))
{
return(new STOutput(BigInteger.ValueOf((long)c), primeSeed, primeGenCounter));
}
if (primeGenCounter > (4 * length))
{
throw new InvalidOperationException("Too many iterations in Shawe-Taylor Random_Prime Routine");
}
}
}
STOutput rec = ImplSTRandomPrime(d, (length + 3) / 2, primeSeed);
{
BigInteger c0 = rec.Prime;
primeSeed = rec.PrimeSeed;
int primeGenCounter = rec.PrimeGenCounter;
int outlen = 8 * dLen;
int iterations = (length - 1) / outlen;
int oldCounter = primeGenCounter;
BigInteger x = HashGen(d, primeSeed, iterations + 1);
x = x.Mod(One.ShiftLeft(length - 1)).SetBit(length - 1);
BigInteger c0x2 = c0.ShiftLeft(1);
BigInteger tx2 = x.Subtract(One).Divide(c0x2).Add(One).ShiftLeft(1);
int dt = 0;
BigInteger c = tx2.Multiply(c0).Add(One);
/*
* TODO Since the candidate primes are generated by constant steps ('c0x2'),
* sieving could be used here in place of the 'HasAnySmallFactors' approach.
*/
for (;;)
{
if (c.BitLength > length)
{
tx2 = One.ShiftLeft(length - 1).Subtract(One).Divide(c0x2).Add(One).ShiftLeft(1);
c = tx2.Multiply(c0).Add(One);
}
++primeGenCounter;
/*
* This is an optimization of the original algorithm, using trial division to screen out
* many non-primes quickly.
*
* NOTE: 'primeSeed' is still incremented as if we performed the full check!
*/
if (!ImplHasAnySmallFactors(c))
{
BigInteger a = HashGen(d, primeSeed, iterations + 1);
a = a.Mod(c.Subtract(Three)).Add(Two);
tx2 = tx2.Add(BigInteger.ValueOf(dt));
dt = 0;
BigInteger z = a.ModPow(tx2, c);
if (c.Gcd(z.Subtract(One)).Equals(One) && z.ModPow(c0, c).Equals(One))
{
return(new STOutput(c, primeSeed, primeGenCounter));
}
}
else
{
Inc(primeSeed, iterations + 1);
}
if (primeGenCounter >= ((4 * length) + oldCounter))
{
throw new InvalidOperationException("Too many iterations in Shawe-Taylor Random_Prime Routine");
}
dt += 2;
c = c.Add(c0x2);
}
}
}
private static STOutput ImplSTRandomPrime(IDigest d, int length, byte[] primeSeed)
{
//IL_0093: Unknown result type (might be due to invalid IL or missing references)
//IL_024d: Unknown result type (might be due to invalid IL or missing references)
int digestSize = d.GetDigestSize();
if (length < 33)
{
int num = 0;
byte[] array = new byte[digestSize];
byte[] array2 = new byte[digestSize];
do
{
Hash(d, primeSeed, array, 0);
Inc(primeSeed, 1);
Hash(d, primeSeed, array2, 0);
Inc(primeSeed, 1);
uint num2 = Extract32(array) ^ Extract32(array2);
num2 &= 4294967295u >> 32 - length;
num2 |= (uint)(1 << length - 1) | 1u;
num++;
if (IsPrime32(num2))
{
return(new STOutput(BigInteger.ValueOf(num2), primeSeed, num));
}
}while (num <= 4 * length);
throw new InvalidOperationException("Too many iterations in Shawe-Taylor Random_Prime Routine");
}
STOutput sTOutput = ImplSTRandomPrime(d, (length + 3) / 2, primeSeed);
BigInteger prime = sTOutput.Prime;
primeSeed = sTOutput.PrimeSeed;
int num3 = sTOutput.PrimeGenCounter;
int num4 = 8 * digestSize;
int num5 = (length - 1) / num4;
int num6 = num3;
BigInteger bigInteger = HashGen(d, primeSeed, num5 + 1);
bigInteger = bigInteger.Mod(One.ShiftLeft(length - 1)).SetBit(length - 1);
BigInteger bigInteger2 = prime.ShiftLeft(1);
BigInteger bigInteger3 = bigInteger.Subtract(One).Divide(bigInteger2).Add(One)
.ShiftLeft(1);
int num7 = 0;
BigInteger bigInteger4 = bigInteger3.Multiply(prime).Add(One);
while (true)
{
if (bigInteger4.BitLength > length)
{
bigInteger3 = One.ShiftLeft(length - 1).Subtract(One).Divide(bigInteger2)
.Add(One)
.ShiftLeft(1);
bigInteger4 = bigInteger3.Multiply(prime).Add(One);
}
num3++;
if (!ImplHasAnySmallFactors(bigInteger4))
{
BigInteger bigInteger5 = HashGen(d, primeSeed, num5 + 1);
bigInteger5 = bigInteger5.Mod(bigInteger4.Subtract(Three)).Add(Two);
bigInteger3 = bigInteger3.Add(BigInteger.ValueOf(num7));
num7 = 0;
BigInteger bigInteger6 = bigInteger5.ModPow(bigInteger3, bigInteger4);
if (bigInteger4.Gcd(bigInteger6.Subtract(One)).Equals(One) && bigInteger6.ModPow(prime, bigInteger4).Equals(One))
{
return(new STOutput(bigInteger4, primeSeed, num3));
}
}
else
{
Inc(primeSeed, num5 + 1);
}
if (num3 >= 4 * length + num6)
{
break;
}
num7 += 2;
bigInteger4 = bigInteger4.Add(bigInteger2);
}
throw new InvalidOperationException("Too many iterations in Shawe-Taylor Random_Prime Routine");
}
