<PackageReference Include="BouncyCastle.Cryptography" Version="2.6.1" />

Primes

public static class Primes
Utility methods for generating primes and testing for primality.
using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Utilities; using Org.BouncyCastle.Security; using Org.BouncyCastle.Utilities; using System; namespace Org.BouncyCastle.Math { public static class Primes { public sealed class MROutput { private readonly bool m_provablyComposite; private readonly BigInteger m_factor; public BigInteger Factor => m_factor; public bool IsProvablyComposite => m_provablyComposite; public bool IsNotPrimePower { get { if (m_provablyComposite) return m_factor == null; return false; } } internal static MROutput ProbablyPrime() { return new MROutput(false, null); } internal static MROutput ProvablyCompositeWithFactor(BigInteger factor) { return new MROutput(true, factor); } internal static MROutput ProvablyCompositeNotPrimePower() { return new MROutput(true, null); } private MROutput(bool provablyComposite, BigInteger factor) { m_provablyComposite = provablyComposite; m_factor = factor; } } public sealed class STOutput { private readonly BigInteger m_prime; private readonly byte[] m_primeSeed; private readonly int m_primeGenCounter; public BigInteger Prime => m_prime; public byte[] PrimeSeed => m_primeSeed; public int PrimeGenCounter => m_primeGenCounter; internal STOutput(BigInteger prime, byte[] primeSeed, int primeGenCounter) { m_prime = prime; m_primeSeed = primeSeed; m_primeGenCounter = primeGenCounter; } } public static readonly int SmallFactorLimit = 211; private static readonly BigInteger One = BigInteger.One; private static readonly BigInteger Two = BigInteger.Two; private static readonly BigInteger Three = BigInteger.Three; public static STOutput GenerateSTRandomPrime(IDigest hash, int length, byte[] inputSeed) { if (hash == null) throw new ArgumentNullException("hash"); if (length < 2) throw new ArgumentException("must be >= 2", "length"); if (inputSeed == null) throw new ArgumentNullException("inputSeed"); if (inputSeed.Length == 0) throw new ArgumentException("cannot be empty", "inputSeed"); return ImplSTRandomPrime(hash, length, Arrays.Clone(inputSeed)); } public static MROutput EnhancedMRProbablePrimeTest(BigInteger candidate, SecureRandom random, int iterations) { CheckCandidate(candidate, "candidate"); if (random == null) throw new ArgumentNullException("random"); if (iterations < 1) throw new ArgumentException("must be > 0", "iterations"); if (candidate.BitLength == 2) return MROutput.ProbablyPrime(); if (!candidate.TestBit(0)) return MROutput.ProvablyCompositeWithFactor(Two); BigInteger bigInteger = candidate.Subtract(One); BigInteger max = candidate.Subtract(Two); int lowestSetBit = bigInteger.GetLowestSetBit(); BigInteger e = bigInteger.ShiftRight(lowestSetBit); for (int i = 0; i < iterations; i++) { BigInteger bigInteger2 = BigIntegers.CreateRandomInRange(Two, max, random); BigInteger bigInteger3 = bigInteger2.Gcd(candidate); if (bigInteger3.CompareTo(One) > 0) return MROutput.ProvablyCompositeWithFactor(bigInteger3); BigInteger bigInteger4 = bigInteger2.ModPow(e, candidate); if (!bigInteger4.Equals(One) && !bigInteger4.Equals(bigInteger)) { bool flag = false; BigInteger bigInteger5 = bigInteger4; for (int j = 1; j < lowestSetBit; j++) { bigInteger4 = bigInteger4.Square().Mod(candidate); if (bigInteger4.Equals(bigInteger)) { flag = true; break; } if (bigInteger4.Equals(One)) break; bigInteger5 = bigInteger4; } if (!flag) { if (!bigInteger4.Equals(One)) { bigInteger5 = bigInteger4; bigInteger4 = bigInteger4.Square().Mod(candidate); if (!bigInteger4.Equals(One)) bigInteger5 = bigInteger4; } bigInteger3 = bigInteger5.Subtract(One).Gcd(candidate); if (bigInteger3.CompareTo(One) > 0) return MROutput.ProvablyCompositeWithFactor(bigInteger3); return MROutput.ProvablyCompositeNotPrimePower(); } } } return MROutput.ProbablyPrime(); } public static bool HasAnySmallFactors(BigInteger candidate) { CheckCandidate(candidate, "candidate"); return ImplHasAnySmallFactors(candidate); } public static bool IsMRProbablePrime(BigInteger candidate, SecureRandom random, int iterations) { CheckCandidate(candidate, "candidate"); if (random == null) throw new ArgumentException("cannot be null", "random"); if (iterations < 1) throw new ArgumentException("must be > 0", "iterations"); if (candidate.BitLength == 2) return true; if (!candidate.TestBit(0)) return false; BigInteger bigInteger = candidate.Subtract(One); BigInteger max = candidate.Subtract(Two); int lowestSetBit = bigInteger.GetLowestSetBit(); BigInteger m = bigInteger.ShiftRight(lowestSetBit); for (int i = 0; i < iterations; i++) { BigInteger b = BigIntegers.CreateRandomInRange(Two, max, random); if (!ImplMRProbablePrimeToBase(candidate, bigInteger, m, lowestSetBit, b)) return false; } return true; } public static bool IsMRProbablePrimeToBase(BigInteger candidate, BigInteger baseValue) { CheckCandidate(candidate, "candidate"); CheckCandidate(baseValue, "baseValue"); if (baseValue.CompareTo(candidate.Subtract(One)) >= 0) throw new ArgumentException("must be < ('candidate' - 1)", "baseValue"); if (candidate.BitLength == 2) return true; BigInteger bigInteger = candidate.Subtract(One); int lowestSetBit = bigInteger.GetLowestSetBit(); BigInteger m = bigInteger.ShiftRight(lowestSetBit); return ImplMRProbablePrimeToBase(candidate, bigInteger, m, lowestSetBit, baseValue); } private static void CheckCandidate(BigInteger n, string name) { if (n == null || n.SignValue < 1 || n.BitLength < 2) throw new ArgumentException("must be non-null and >= 2", name); } private static bool ImplHasAnySmallFactors(BigInteger x) { int value = 223092870; int intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 2 == 0 || intValue % 3 == 0 || intValue % 5 == 0 || intValue % 7 == 0 || intValue % 11 == 0 || intValue % 13 == 0 || intValue % 17 == 0 || intValue % 19 == 0 || intValue % 23 == 0) return true; value = 58642669; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 29 == 0 || intValue % 31 == 0 || intValue % 37 == 0 || intValue % 41 == 0 || intValue % 43 == 0) return true; value = 600662303; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 47 == 0 || intValue % 53 == 0 || intValue % 59 == 0 || intValue % 61 == 0 || intValue % 67 == 0) return true; value = 33984931; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 71 == 0 || intValue % 73 == 0 || intValue % 79 == 0 || intValue % 83 == 0) return true; value = 89809099; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 89 == 0 || intValue % 97 == 0 || intValue % 101 == 0 || intValue % 103 == 0) return true; value = 167375713; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 107 == 0 || intValue % 109 == 0 || intValue % 113 == 0 || intValue % 127 == 0) return true; value = 371700317; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 131 == 0 || intValue % 137 == 0 || intValue % 139 == 0 || intValue % 149 == 0) return true; value = 645328247; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 151 == 0 || intValue % 157 == 0 || intValue % 163 == 0 || intValue % 167 == 0) return true; value = 1070560157; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 173 == 0 || intValue % 179 == 0 || intValue % 181 == 0 || intValue % 191 == 0) return true; value = 1596463769; intValue = x.Mod(BigInteger.ValueOf(value)).IntValue; if (intValue % 193 == 0 || intValue % 197 == 0 || intValue % 199 == 0 || intValue % 211 == 0) return true; return false; } private static bool ImplMRProbablePrimeToBase(BigInteger w, BigInteger wSubOne, BigInteger m, int a, BigInteger b) { BigInteger bigInteger = b.ModPow(m, w); if (bigInteger.Equals(One) || bigInteger.Equals(wSubOne)) return true; for (int i = 1; i < a; i++) { bigInteger = bigInteger.Square().Mod(w); if (bigInteger.Equals(wSubOne)) return true; if (bigInteger.Equals(One)) return false; } return false; } private static STOutput ImplSTRandomPrime(IDigest d, int length, byte[] primeSeed) { int digestSize = d.GetDigestSize(); int num = System.Math.Max(4, digestSize); if (length < 33) { int num2 = 0; byte[] array = new byte[num]; byte[] array2 = new byte[num]; do { Hash(d, primeSeed, array, num - digestSize); Inc(primeSeed, 1); Hash(d, primeSeed, array2, num - digestSize); Inc(primeSeed, 1); uint num3 = Pack.BE_To_UInt32(array, num - 4) ^ Pack.BE_To_UInt32(array2, num - 4); num3 &= uint.MaxValue >> 32 - length; num3 = (uint)((int)num3 | ((1 << length - 1) | 1)); num2++; if (IsPrime32(num3)) return new STOutput(BigInteger.ValueOf(num3), primeSeed, num2); } while (num2 <= 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 num4 = sTOutput.PrimeGenCounter; int num5 = 8 * digestSize; int num6 = (length - 1) / num5; int num7 = num4; BigInteger bigInteger = HashGen(d, primeSeed, num6 + 1).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 num8 = 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); } num4++; if (ImplHasAnySmallFactors(bigInteger4)) Inc(primeSeed, num6 + 1); else { BigInteger bigInteger5 = HashGen(d, primeSeed, num6 + 1).Mod(bigInteger4.Subtract(Three)).Add(Two); bigInteger3 = bigInteger3.Add(BigInteger.ValueOf(num8)); num8 = 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, num4); } if (num4 >= 4 * length + num7) break; num8 += 2; bigInteger4 = bigInteger4.Add(bigInteger2); } throw new InvalidOperationException("Too many iterations in Shawe-Taylor Random_Prime Routine"); } private static void Hash(IDigest d, byte[] input, byte[] output, int outPos) { d.BlockUpdate(input, 0, input.Length); d.DoFinal(output, outPos); } private static BigInteger HashGen(IDigest d, byte[] seed, int count) { int digestSize = d.GetDigestSize(); int num = count * digestSize; byte[] array = new byte[num]; for (int i = 0; i < count; i++) { num -= digestSize; Hash(d, seed, array, num); Inc(seed, 1); } return new BigInteger(1, array); } private static void Inc(byte[] seed, int c) { int num = seed.Length; while (c > 0 && --num >= 0) { c += seed[num]; seed[num] = (byte)c; c >>= 8; } } private static bool IsPrime32(uint x) { if (x < 32) return ((1 << (int)x) & 545925292) != 0; if (((1 << (int)(x % 30)) & 2693408898) == 0) return false; uint[] array = new uint[8] { 1, 7, 11, 13, 17, 19, 23, 29 }; uint num = 0; int num2 = 1; while (true) { if (num2 < array.Length) { uint num3 = num + array[num2]; if (x % num3 == 0) return false; num2++; } else { num += 30; if (num >> 16 != 0 || num * num >= x) break; num2 = 0; } } return true; } } }