102 lines
3.5 KiB
C++
102 lines
3.5 KiB
C++
/*
|
|
Copyright (c) 2009-2010 Christopher A. Taylor. All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are met:
|
|
|
|
* Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions and the following disclaimer.
|
|
* Redistributions in binary form must reproduce the above copyright notice,
|
|
this list of conditions and the following disclaimer in the documentation
|
|
and/or other materials provided with the distribution.
|
|
* Neither the name of LibCat nor the names of its contributors may be used
|
|
to endorse or promote products derived from this software without
|
|
specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
Several algorithms based on ideas from the "Handbook of Applied Cryptography"
|
|
http://www.cacr.math.uwaterloo.ca/hac/
|
|
*/
|
|
|
|
#ifndef CAT_BIG_MONTGOMERY_HPP
|
|
#define CAT_BIG_MONTGOMERY_HPP
|
|
|
|
#include <cat/math/BigRTL.hpp>
|
|
#include <cat/rand/IRandom.hpp>
|
|
|
|
namespace cat {
|
|
|
|
|
|
// Performs fast modular arithmetic in the Montgomery Residue Number System
|
|
class BigMontgomery : public BigRTL
|
|
{
|
|
static const int MON_OVERHEAD = 3 + 4;
|
|
int mon_regs;
|
|
|
|
protected:
|
|
Leg *TempProduct;
|
|
Leg *TempProductHi;
|
|
Leg *CachedModulus;
|
|
Leg mod_inv;
|
|
|
|
public:
|
|
BigMontgomery(int regs, int bits);
|
|
|
|
// Must call SetModulus() before using this object
|
|
void SetModulus(const Leg *mod);
|
|
|
|
public:
|
|
const Leg *GetModulus() { return CachedModulus; }
|
|
void CopyModulus(Leg *out);
|
|
|
|
public:
|
|
// Convert value in register into RNS, stored in out
|
|
void MonInput(const Leg *in, Leg *out);
|
|
|
|
// Convert value in register from RNS, stored in out
|
|
void MonOutput(const Leg *in, Leg *out);
|
|
|
|
// Note: This will clobber the input product!
|
|
// Reduce a double-register product to a single register in the RNS
|
|
void MonReduceProduct(Leg *inout_product, Leg *out);
|
|
|
|
public:
|
|
// Inputs and outputs must be in the Montgomery RNS
|
|
void MonAdd(const Leg *in_a, const Leg *in_b, Leg *out);
|
|
void MonSubtract(const Leg *in_a, const Leg *in_b, Leg *out);
|
|
void MonNegate(const Leg *in, Leg *out);
|
|
void MonDouble(const Leg *in, Leg *out);
|
|
|
|
public:
|
|
// Inputs and outputs must be in the Montgomery RNS
|
|
void MonMultiply(const Leg *in_a, const Leg *in_b, Leg *out);
|
|
void MonSquare(const Leg *in, Leg *out);
|
|
|
|
public:
|
|
// Base must be in the Montgomery RNS. in_base != out
|
|
void MonExpMod(const Leg *in_base, const Leg *in_exp, Leg *out);
|
|
|
|
public:
|
|
// Input is NOT in the RNS (don't call MonInput)
|
|
// Probably a prime, certainty = 4^-trials. 20: %99.9999999999 certainty
|
|
bool IsRabinMillerPrime(IRandom *prng, const Leg *n, int trials = 20);
|
|
};
|
|
|
|
|
|
} // namespace cat
|
|
|
|
#endif // CAT_BIG_MONTGOMERY_HPP
|