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public ModPow ( |
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| exponent | ||
| m | ||
| return | ||
public BigInteger ProcessBlock(
BigInteger input)
{
if (key is RsaPrivateCrtKeyParameters)
{
//
// we have the extra factors, use the Chinese Remainder Theorem - the author
// wishes to express his thanks to Dirk Bonekaemper at rtsffm.com for
// advice regarding the expression of this.
//
RsaPrivateCrtKeyParameters crtKey = (RsaPrivateCrtKeyParameters)key;
BigInteger p = crtKey.P;;
BigInteger q = crtKey.Q;
BigInteger dP = crtKey.DP;
BigInteger dQ = crtKey.DQ;
BigInteger qInv = crtKey.QInv;
BigInteger mP, mQ, h, m;
// mP = ((input Mod p) ^ dP)) Mod p
mP = (input.Remainder(p)).ModPow(dP, p);
// mQ = ((input Mod q) ^ dQ)) Mod q
mQ = (input.Remainder(q)).ModPow(dQ, q);
// h = qInv * (mP - mQ) Mod p
h = mP.Subtract(mQ);
h = h.Multiply(qInv);
h = h.Mod(p); // Mod (in Java) returns the positive residual
// m = h * q + mQ
m = h.Multiply(q);
m = m.Add(mQ);
return m;
}
return input.ModPow(key.Exponent, key.Modulus);
}
internal bool RabinMillerTest(
int certainty,
Random random)
{
Debug.Assert(certainty > 0);
Debug.Assert(BitLength > 2);
Debug.Assert(TestBit(0));
// let n = 1 + d . 2^s
BigInteger n = this;
BigInteger nMinusOne = n.Subtract(One);
int s = nMinusOne.GetLowestSetBit();
BigInteger r = nMinusOne.ShiftRight(s);
Debug.Assert(s >= 1);
do
{
// TODO Make a method for random BigIntegers in range 0 < x < n)
// - Method can be optimized by only replacing examined bits at each trial
BigInteger a;
do
{
a = new BigInteger(n.BitLength, random);
}
while (a.CompareTo(One) <= 0 || a.CompareTo(nMinusOne) >= 0);
BigInteger y = a.ModPow(r, n);
if (!y.Equals(One))
{
int j = 0;
while (!y.Equals(nMinusOne))
{
if (++j == s)
return false;
y = y.ModPow(Two, n);
if (y.Equals(One))
return false;
}
}
certainty -= 2; // composites pass for only 1/4 possible 'a'
}
while (certainty > 0);
return true;
}