private DSA_Secret_Key GenerateParams(int keyLength) { byte[] seed = new byte[20]; byte[] part1 = new byte[20]; byte[] part2 = new byte[20]; byte[] u = new byte[20]; RandomNumberGenerator rng = RandomNumberGenerator.Create(); BigInteger p = new BigInteger(); // prime BigInteger q = new BigInteger(); // group order BigInteger g; // group generator DSA_Secret_Key dskKey = new DSA_Secret_Key(); SHA1 sha = SHA1.Create(); int n = (keyLength - 1) / 160; byte[] w = new byte [keyLength / 8]; bool primesFound = false; while (!primesFound) { do { rng.GetBytes(seed); part1 = sha.ComputeHash(seed); Array.Copy(seed, 0, part2, 0, seed.Length); add(part2, seed, 1); part2 = sha.ComputeHash(part2); for (int i = 0; i != u.Length; i++) u[i] = (byte)(part1[i] ^ part2[i]); // first bit must be set (to respect key length) u[0] |= (byte)0x80; // last bit must be set (prime are all odds - except 2) u[19] |= (byte)0x01; q = new BigInteger(u); } while (!q.isProbablePrime()); int counter = 0; int offset = 2; while (counter < 4096) { for (int k = 0; k < n; k++) { add(part1, seed, offset + k); part1 = sha.ComputeHash(part1); Array.Copy(part1, 0, w, w.Length - (k + 1) * part1.Length, part1.Length); } add(part1, seed, offset + n); part1 = sha.ComputeHash(part1); Array.Copy(part1, part1.Length - ((w.Length - (n) * part1.Length)), w, 0, w.Length - n * part1.Length); w[0] |= (byte)0x80; BigInteger xx = new BigInteger (w); BigInteger c = xx % (q * 2); p = xx - (c - 1); if (p.testBit((uint)(keyLength - 1))) { if (p.isProbablePrime()) { primesFound = true; break; } } counter += 1; offset += n + 1; } } // calculate the generator g BigInteger pMinusOneOverQ = (p - 1) / q; for (;;) { BigInteger h = new BigInteger(); h = BigInteger.genRandom(keyLength); if ((h <= 1) || (h >= (p - 1))) continue; g = h.modPow(pMinusOneOverQ, p); if (g <= 1) continue; break; } dskKey.p = p; dskKey.q = q; dskKey.g = g; return dskKey; }
private unsafe BigInteger OddPow (uint b, BigInteger exp) { exp.Normalize (); uint [] wkspace = new uint [mod.length << 1 + 1]; BigInteger resultNum = Montgomery.ToMont ((BigInteger)b, this.mod); resultNum = new BigInteger (resultNum, mod.length << 1 +1); uint mPrime = Montgomery.Inverse (mod.data [0]); uint pos = (uint)exp.bitCount () - 2; // // We know that the first itr will make the val b // do { // // r = r ^ 2 % m // Kernel.SquarePositive (resultNum, ref wkspace); resultNum = Montgomery.Reduce (resultNum, mod, mPrime); if (exp.testBit (pos)) { // // r = r * b % m // // TODO: Is Unsafe really speeding things up? fixed (uint* u = resultNum.data) { uint i = 0; ulong mc = 0; do { mc += (ulong)u [i] * (ulong)b; u [i] = (uint)mc; mc >>= 32; } while (++i < resultNum.length); if (resultNum.length < mod.length) { if (mc != 0) { u [i] = (uint)mc; resultNum.length++; while (resultNum >= mod) Kernel.MinusEq (resultNum, mod); } } else if (mc != 0) { // // First, we estimate the quotient by dividing // the first part of each of the numbers. Then // we correct this, if necessary, with a subtraction. // uint cc = (uint)mc; // We would rather have this estimate overshoot, // so we add one to the divisor uint divEstimate = (uint) ((((ulong)cc << 32) | (ulong) u [i -1]) / (mod.data [mod.length-1] + 1)); uint t; i = 0; mc = 0; do { mc += (ulong)mod.data [i] * (ulong)divEstimate; t = u [i]; u [i] -= (uint)mc; mc >>= 32; if (u [i] > t) mc++; i++; } while (i < resultNum.length); cc -= (uint)mc; if (cc != 0) { uint sc = 0, j = 0; uint [] s = mod.data; do { uint a = s [j]; if (((a += sc) < sc) | ((u [j] -= a) > ~a)) sc = 1; else sc = 0; j++; } while (j < resultNum.length); cc -= sc; } while (resultNum >= mod) Kernel.MinusEq (resultNum, mod); } else { while (resultNum >= mod) Kernel.MinusEq (resultNum, mod); } } } } while (pos-- > 0); resultNum = Montgomery.Reduce (resultNum, mod, mPrime); return resultNum; }
public BigInteger EvenPow (BigInteger b, BigInteger exp) { BigInteger resultNum = new BigInteger ((BigInteger)1, mod.length << 1); BigInteger tempNum = new BigInteger (b % mod, mod.length << 1); // ensures (tempNum * tempNum) < b^ (2k) uint totalBits = (uint)exp.bitCount (); uint [] wkspace = new uint [mod.length << 1]; // perform squaring and multiply exponentiation for (uint pos = 0; pos < totalBits; pos++) { if (exp.testBit (pos)) { Array.Clear (wkspace, 0, wkspace.Length); Kernel.Multiply (resultNum.data, 0, resultNum.length, tempNum.data, 0, tempNum.length, wkspace, 0); resultNum.length += tempNum.length; uint [] t = wkspace; wkspace = resultNum.data; resultNum.data = t; BarrettReduction (resultNum); } Kernel.SquarePositive (tempNum, ref wkspace); BarrettReduction (tempNum); if (tempNum == 1) { return resultNum; } } return resultNum; }
private BigInteger OddPow (BigInteger b, BigInteger exp) { BigInteger resultNum = new BigInteger (Montgomery.ToMont (1, mod), mod.length << 1); BigInteger tempNum = new BigInteger (Montgomery.ToMont (b, mod), mod.length << 1); // ensures (tempNum * tempNum) < b^ (2k) uint mPrime = Montgomery.Inverse (mod.data [0]); uint totalBits = (uint)exp.bitCount (); uint [] wkspace = new uint [mod.length << 1]; // perform squaring and multiply exponentiation for (uint pos = 0; pos < totalBits; pos++) { if (exp.testBit (pos)) { Array.Clear (wkspace, 0, wkspace.Length); Kernel.Multiply (resultNum.data, 0, resultNum.length, tempNum.data, 0, tempNum.length, wkspace, 0); resultNum.length += tempNum.length; uint [] t = wkspace; wkspace = resultNum.data; resultNum.data = t; Montgomery.Reduce (resultNum, mod, mPrime); } Kernel.SquarePositive (tempNum, ref wkspace); Montgomery.Reduce (tempNum, mod, mPrime); } Montgomery.Reduce (resultNum, mod, mPrime); return resultNum; }
private unsafe BigInteger OddModTwoPow (BigInteger exp) { uint [] wkspace = new uint [mod.length << 1 + 1]; BigInteger resultNum = Montgomery.ToMont ((BigInteger)2, this.mod); resultNum = new BigInteger (resultNum, mod.length << 1 +1); uint mPrime = Montgomery.Inverse (mod.data [0]); // // TODO: eat small bits, the ones we can do with no modular reduction // uint pos = (uint)exp.bitCount () - 2; do { Kernel.SquarePositive (resultNum, ref wkspace); resultNum = Montgomery.Reduce (resultNum, mod, mPrime); if (exp.testBit (pos)) { // // resultNum = (resultNum * 2) % mod // fixed (uint* u = resultNum.data) { // // Double // uint* uu = u; uint* uuE = u + resultNum.length; uint x, carry = 0; while (uu < uuE) { x = *uu; *uu = (x << 1) | carry; carry = x >> (32 - 1); uu++; } // subtraction inlined because we know it is square if (carry != 0 || resultNum >= mod) { fixed (uint* s = mod.data) { uu = u; uint c = 0; uint* ss = s; do { uint a = *ss++; if (((a += c) < c) | ((* (uu++) -= a) > ~a)) c = 1; else c = 0; } while (uu < uuE); } } } } } while (pos-- > 0); resultNum = Montgomery.Reduce (resultNum, mod, mPrime); return resultNum; }