1
0
mirror of https://github.com/danog/ton.git synced 2024-12-02 09:28:02 +01:00
ton/crypto/ellcurve/Montgomery.h
2019-09-07 14:33:36 +04:00

124 lines
3.2 KiB
C++

/*
This file is part of TON Blockchain Library.
TON Blockchain Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
TON Blockchain Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
Copyright 2017-2019 Telegram Systems LLP
*/
#pragma once
#include <iostream>
#include <string>
#include "openssl/bignum.h"
#include "openssl/residue.h"
#include "ellcurve/Fp25519.h"
namespace ellcurve {
using namespace arith;
class MontgomeryCurve {
td::Ref<ResidueRing> ring;
int A_short; // v^2 = u^2 + Au + 1
int Gu_short; // u(G)
int a_short; // (A+2)/4
Residue A_;
Residue Gu;
Bignum P_;
Bignum L;
Bignum Order;
Bignum cofactor;
int cofactor_short;
void init();
public:
MontgomeryCurve(int _A, int _Gu, td::Ref<ResidueRing> _R)
: ring(_R)
, A_short(_A)
, Gu_short(_Gu)
, a_short((_A + 2) / 4)
, A_(_A, _R)
, Gu(_Gu, _R)
, P_(_R->get_modulus())
, cofactor_short(0) {
init();
}
const Residue& get_gen_u() const {
return Gu;
}
const Bignum& get_ell() const {
return L;
}
const Bignum& get_order() const {
return Order;
}
td::Ref<ResidueRing> get_base_ring() const {
return ring;
}
const Bignum& get_p() const {
return P_;
}
void set_order_cofactor(const Bignum& order, int cof);
struct PointXZ {
Residue X, Z;
PointXZ(Residue x, Residue z) : X(x), Z(z) {
x.same_ring(z);
}
PointXZ(td::Ref<ResidueRing> r) : X(r->one()), Z(r->zero()) {
}
explicit PointXZ(Residue u) : X(u), Z(u.ring_of().one()) {
}
explicit PointXZ(Residue y, bool) : X(y.ring_of().one() + y), Z(y.ring_of().one() - y) {
}
PointXZ(const PointXZ& P) : X(P.X), Z(P.Z) {
}
PointXZ& operator=(const PointXZ& P) {
X = P.X;
Z = P.Z;
return *this;
}
Residue get_u() const {
return X * inverse(Z);
}
Residue get_v(bool sign_v = false) const;
bool is_infty() const {
return Z.is_zero();
}
Residue get_y() const {
return (X - Z) * inverse(X + Z);
}
bool export_point_y(unsigned char buffer[32]) const;
bool export_point_u(unsigned char buffer[32]) const;
void zeroize() {
X = Z = Z.ring_of().zero();
}
};
PointXZ power_gen_xz(const Bignum& n) const;
PointXZ power_xz(const Residue& u, const Bignum& n) const;
PointXZ power_xz(const PointXZ& P, const Bignum& n) const;
PointXZ add_xz(const PointXZ& P, const PointXZ& Q) const;
PointXZ double_xz(const PointXZ& P) const;
PointXZ import_point_u(const unsigned char point[32]) const;
PointXZ import_point_y(const unsigned char point[32]) const;
};
const MontgomeryCurve& Curve25519();
} // namespace ellcurve