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;
}