a portable and fast pairing-based cryptography library
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
mcl/include/mcl/bn.hpp

1956 lines
42 KiB

#pragma once
/**
@file
@brief optimal ate pairing over BN-curve / BLS12-curve
@author MITSUNARI Shigeo(@herumi)
@license modified new BSD license
http://opensource.org/licenses/BSD-3-Clause
*/
#include <mcl/fp_tower.hpp>
#include <mcl/ec.hpp>
#include <mcl/curve_type.h>
#include <assert.h>
#include <vector>
/*
set bit size of Fp and Fr
*/
#ifndef MCL_MAX_FP_BIT_SIZE
#define MCL_MAX_FP_BIT_SIZE 256
#endif
#ifndef MCL_MAX_FR_BIT_SIZE
#define MCL_MAX_FR_BIT_SIZE MCL_MAX_FP_BIT_SIZE
#endif
namespace mcl {
struct CurveParam {
/*
y^2 = x^3 + b
i^2 = -1
xi = xi_a + i
v^3 = xi
w^2 = v
*/
const char *z;
int b; // y^2 = x^3 + b
int xi_a; // xi = xi_a + i
/*
BN254, BN381 : Dtype
BLS12-381 : Mtype
*/
bool isMtype;
int curveType; // same in curve_type.h
bool operator==(const CurveParam& rhs) const
{
return std::string(z) == rhs.z && b == rhs.b && xi_a == rhs.xi_a && isMtype == rhs.isMtype;
}
bool operator!=(const CurveParam& rhs) const { return !operator==(rhs); }
};
const CurveParam BN254 = { "-0x4080000000000001", 2, 1, false, MCL_BN254 }; // -(2^62 + 2^55 + 1)
// provisional(experimental) param with maxBitSize = 384
const CurveParam BN381_1 = { "-0x400011000000000000000001", 2, 1, false, MCL_BN381_1 }; // -(2^94 + 2^76 + 2^72 + 1) // A Family of Implementation-Friendly BN Elliptic Curves
const CurveParam BN381_2 = { "-0x400040090001000000000001", 2, 1, false, MCL_BN381_2 }; // -(2^94 + 2^78 + 2^67 + 2^64 + 2^48 + 1) // used in relic-toolkit
const CurveParam BN462 = { "0x4001fffffffffffffffffffffbfff", 5, 2, false, MCL_BN462 }; // 2^114 + 2^101 - 2^14 - 1 // https://eprint.iacr.org/2017/334
const CurveParam BN_SNARK1 = { "4965661367192848881", 3, 9, false, MCL_BN_SNARK1 };
const CurveParam BLS12_381 = { "-0xd201000000010000", 4, 1, true, MCL_BLS12_381 };
inline const CurveParam& getCurveParam(int type)
{
switch (type) {
case MCL_BN254: return mcl::BN254;
case MCL_BN381_1: return mcl::BN381_1;
case MCL_BN381_2: return mcl::BN381_2;
case MCL_BN462: return mcl::BN462;
case MCL_BN_SNARK1: return mcl::BN_SNARK1;
case MCL_BLS12_381: return mcl::BLS12_381;
default:
throw cybozu::Exception("getCurveParam:bad type") << type;
}
}
namespace bn {
namespace local {
struct FpTag;
struct FrTag;
}
typedef mcl::FpT<local::FpTag, MCL_MAX_FP_BIT_SIZE> Fp;
typedef mcl::FpT<local::FrTag, MCL_MAX_FR_BIT_SIZE> Fr;
typedef mcl::Fp2T<Fp> Fp2;
typedef mcl::Fp6T<Fp> Fp6;
typedef mcl::Fp12T<Fp> Fp12;
typedef mcl::EcT<Fp> G1;
typedef mcl::EcT<Fp2> G2;
typedef Fp12 GT;
typedef mcl::FpDblT<Fp> FpDbl;
typedef mcl::Fp2DblT<Fp> Fp2Dbl;
inline void Frobenius(Fp2& y, const Fp2& x)
{
Fp2::Frobenius(y, x);
}
inline void Frobenius(Fp12& y, const Fp12& x)
{
Fp12::Frobenius(y, x);
}
/*
twisted Frobenius for G2
*/
void Frobenius(G2& D, const G2& S);
void Frobenius2(G2& D, const G2& S);
void Frobenius3(G2& D, const G2& S);
namespace local {
typedef mcl::Vector<int8_t> SignVec;
inline size_t getPrecomputeQcoeffSize(const SignVec& sv)
{
size_t idx = 2 + 2;
for (size_t i = 2; i < sv.size(); i++) {
idx++;
if (sv[i]) idx++;
}
return idx;
}
template<class X, class C, size_t N>
X evalPoly(const X& x, const C (&c)[N])
{
X ret = c[N - 1];
for (size_t i = 1; i < N; i++) {
ret *= x;
ret += c[N - 1 - i];
}
return ret;
}
enum TwistBtype {
tb_generic,
tb_1m1i, // 1 - 1i
tb_1m2i // 1 - 2i
};
/*
l = (a, b, c) => (a, b * P.y, c * P.x)
*/
inline void updateLine(Fp6& l, const G1& P)
{
l.b.a *= P.y;
l.b.b *= P.y;
l.c.a *= P.x;
l.c.b *= P.x;
}
struct Compress {
Fp12& z_;
Fp2& g1_;
Fp2& g2_;
Fp2& g3_;
Fp2& g4_;
Fp2& g5_;
// z is output area
Compress(Fp12& z, const Fp12& x)
: z_(z)
, g1_(z.getFp2()[4])
, g2_(z.getFp2()[3])
, g3_(z.getFp2()[2])
, g4_(z.getFp2()[1])
, g5_(z.getFp2()[5])
{
g2_ = x.getFp2()[3];
g3_ = x.getFp2()[2];
g4_ = x.getFp2()[1];
g5_ = x.getFp2()[5];
}
Compress(Fp12& z, const Compress& c)
: z_(z)
, g1_(z.getFp2()[4])
, g2_(z.getFp2()[3])
, g3_(z.getFp2()[2])
, g4_(z.getFp2()[1])
, g5_(z.getFp2()[5])
{
g2_ = c.g2_;
g3_ = c.g3_;
g4_ = c.g4_;
g5_ = c.g5_;
}
void decompressBeforeInv(Fp2& nume, Fp2& denomi) const
{
assert(&nume != &denomi);
if (g2_.isZero()) {
Fp2::add(nume, g4_, g4_);
nume *= g5_;
denomi = g3_;
} else {
Fp2 t;
Fp2::sqr(nume, g5_);
Fp2::mul_xi(denomi, nume);
Fp2::sqr(nume, g4_);
Fp2::sub(t, nume, g3_);
t += t;
t += nume;
Fp2::add(nume, denomi, t);
Fp2::divBy4(nume, nume);
denomi = g2_;
}
}
// output to z
void decompressAfterInv()
{
Fp2& g0 = z_.getFp2()[0];
Fp2 t0, t1;
// Compute g0.
Fp2::sqr(t0, g1_);
Fp2::mul(t1, g3_, g4_);
t0 -= t1;
t0 += t0;
t0 -= t1;
Fp2::mul(t1, g2_, g5_);
t0 += t1;
Fp2::mul_xi(g0, t0);
g0.a += Fp::one();
}
public:
void decompress() // for test
{
Fp2 nume, denomi;
decompressBeforeInv(nume, denomi);
Fp2::inv(denomi, denomi);
g1_ = nume * denomi; // g1 is recoverd.
decompressAfterInv();
}
/*
2275clk * 186 = 423Kclk QQQ
*/
static void squareC(Compress& z)
{
Fp2 t0, t1, t2;
Fp2Dbl T0, T1, T2, T3;
Fp2Dbl::sqrPre(T0, z.g4_);
Fp2Dbl::sqrPre(T1, z.g5_);
Fp2Dbl::mul_xi(T2, T1);
T2 += T0;
Fp2Dbl::mod(t2, T2);
Fp2::add(t0, z.g4_, z.g5_);
Fp2Dbl::sqrPre(T2, t0);
T0 += T1;
T2 -= T0;
Fp2Dbl::mod(t0, T2);
Fp2::add(t1, z.g2_, z.g3_);
Fp2Dbl::sqrPre(T3, t1);
Fp2Dbl::sqrPre(T2, z.g2_);
Fp2::mul_xi(t1, t0);
z.g2_ += t1;
z.g2_ += z.g2_;
z.g2_ += t1;
Fp2::sub(t1, t2, z.g3_);
t1 += t1;
Fp2Dbl::sqrPre(T1, z.g3_);
Fp2::add(z.g3_, t1, t2);
Fp2Dbl::mul_xi(T0, T1);
T0 += T2;
Fp2Dbl::mod(t0, T0);
Fp2::sub(z.g4_, t0, z.g4_);
z.g4_ += z.g4_;
z.g4_ += t0;
Fp2Dbl::addPre(T2, T2, T1);
T3 -= T2;
Fp2Dbl::mod(t0, T3);
z.g5_ += t0;
z.g5_ += z.g5_;
z.g5_ += t0;
}
static void square_n(Compress& z, int n)
{
for (int i = 0; i < n; i++) {
squareC(z);
}
}
/*
Exponentiation over compression for:
z = x^Param::z.abs()
*/
static void fixed_power(Fp12& z, const Fp12& x)
{
if (x.isOne()) {
z = 1;
return;
}
Fp12 x_org = x;
Fp12 d62;
Fp2 c55nume, c55denomi, c62nume, c62denomi;
Compress c55(z, x);
square_n(c55, 55);
c55.decompressBeforeInv(c55nume, c55denomi);
Compress c62(d62, c55);
square_n(c62, 62 - 55);
c62.decompressBeforeInv(c62nume, c62denomi);
Fp2 acc;
Fp2::mul(acc, c55denomi, c62denomi);
Fp2::inv(acc, acc);
Fp2 t;
Fp2::mul(t, acc, c62denomi);
Fp2::mul(c55.g1_, c55nume, t);
c55.decompressAfterInv();
Fp2::mul(t, acc, c55denomi);
Fp2::mul(c62.g1_, c62nume, t);
c62.decompressAfterInv();
z *= x_org;
z *= d62;
}
};
struct MapTo {
Fp c1_; // sqrt(-3)
Fp c2_; // (-1 + sqrt(-3)) / 2
mpz_class z_;
mpz_class cofactor_;
bool isBN_;
int legendre(const Fp& x) const
{
return gmp::legendre(x.getMpz(), Fp::getOp().mp);
}
int legendre(const Fp2& x) const
{
Fp y;
Fp2::norm(y, x);
return legendre(y);
}
void mulFp(Fp& x, const Fp& y) const
{
x *= y;
}
void mulFp(Fp2& x, const Fp& y) const
{
x.a *= y;
x.b *= y;
}
/*
P.-A. Fouque and M. Tibouchi,
"Indifferentiable hashing to Barreto Naehrig curves,"
in Proc. Int. Conf. Cryptol. Inform. Security Latin Amer., 2012, vol. 7533, pp.1-17.
w = sqrt(-3) t / (1 + b + t^2)
Remark: throw exception if t = 0, c1, -c1 and b = 2
*/
template<class G, class F>
bool calcBN(G& P, const F& t) const
{
F x, y, w;
bool negative = legendre(t) < 0;
if (t.isZero()) return false;
F::sqr(w, t);
w += G::b_;
*w.getFp0() += Fp::one();
if (w.isZero()) return false;
F::inv(w, w);
mulFp(w, c1_);
w *= t;
for (int i = 0; i < 3; i++) {
switch (i) {
case 0: F::mul(x, t, w); F::neg(x, x); *x.getFp0() += c2_; break;
case 1: F::neg(x, x); *x.getFp0() -= Fp::one(); break;
case 2: F::sqr(x, w); F::inv(x, x); *x.getFp0() += Fp::one(); break;
}
G::getWeierstrass(y, x);
if (F::squareRoot(y, y)) {
if (negative) F::neg(y, y);
P.set(x, y, false);
return true;
}
}
return false;
}
/*
Faster Hashing to G2
Laura Fuentes-Castaneda, Edward Knapp, Francisco Rodriguez-Henriquez
section 6.1
for BN
Q = zP + Frob(3zP) + Frob^2(zP) + Frob^3(P)
= -(18x^3 + 12x^2 + 3x + 1)cofactor_ P
*/
void mulByCofactorBN(G2& Q, const G2& P) const
{
#if 0
G2::mulGeneric(Q, P, cofactor_);
#else
#if 0
mpz_class t = -(1 + z_ * (3 + z_ * (12 + z_ * 18)));
G2::mulGeneric(Q, P, t * cofactor_);
#else
G2 T0, T1, T2;
/*
G2::mul (GLV method) can't be used because P is not on G2
*/
G2::mulGeneric(T0, P, z_);
G2::dbl(T1, T0);
T1 += T0; // 3zP
Frobenius(T1, T1);
Frobenius2(T2, T0);
T0 += T1;
T0 += T2;
Frobenius3(T2, P);
G2::add(Q, T0, T2);
#endif
#endif
}
template<class G, class F>
void naiveMapTo(G& P, const F& t) const
{
F x = t;
for (;;) {
F y;
G::getWeierstrass(y, x);
if (F::squareRoot(y, y)) {
P.set(x, y, false);
return;
}
*x.getFp0() += Fp::one();
}
}
/*
#(Fp) / r = (z + 1 - t) / r = (z - 1)^2 / 3
*/
void mulByCofactorBLS12(G1& Q, const G1& P) const
{
G1::mulGeneric(Q, P, cofactor_);
}
/*
Efficient hash maps to G2 on BLS curves
Alessandro Budroni, Federico Pintore
Q = (z(z-1)-1)P + Frob((z-1)P) + Frob^2(2P)
*/
void mulByCofactorBLS12(G2& Q, const G2& P) const
{
G2 T0, T1;
G2::mulGeneric(T0, P, z_ - 1);
G2::mulGeneric(T1, T0, z_);
T1 -= P;
Frobenius(T0, T0);
T0 += T1;
G2::dbl(T1, P);
Frobenius2(T1, T1);
G2::add(Q, T0, T1);
}
/*
cofactor_ is for G2(not used now)
*/
void initBN(const mpz_class& cofactor, const mpz_class &z)
{
if (!Fp::squareRoot(c1_, -3)) throw cybozu::Exception("MapTo:init:c1_");
c2_ = (c1_ - 1) / 2;
z_ = z;
cofactor_ = cofactor;
}
void initBLS12(const mpz_class& z)
{
z_ = z;
// cofactor for G1
cofactor_ = (z - 1) * (z - 1) / 3;
}
void init(const mpz_class& cofactor, const mpz_class &z, bool isBN)
{
isBN_ = isBN;
if (isBN_) {
initBN(cofactor, z);
} else {
initBLS12(z);
}
}
bool calcG1(G1& P, const Fp& t) const
{
if (isBN_) {
if (!calcBN<G1, Fp>(P, t)) return false;
} else {
naiveMapTo<G1, Fp>(P, t);
mulByCofactorBLS12(P, P);
}
assert(P.isValid());
return true;
}
/*
get the element in G2 by multiplying the cofactor
*/
bool calcG2(G2& P, const Fp2& t) const
{
if (isBN_) {
if (!calcBN<G2, Fp2>(P, t)) return false;
mulByCofactorBN(P, P);
} else {
naiveMapTo<G2, Fp2>(P, t);
mulByCofactorBLS12(P, P);
}
assert(P.isValid());
return true;
}
};
/*
Software implementation of Attribute-Based Encryption: Appendixes
GLV for G1 on BN/BLS12
*/
struct GLV1 {
Fp rw; // rw = 1 / w = (-1 - sqrt(-3)) / 2
size_t rBitSize;
mpz_class v0, v1;
mpz_class B[2][2];
mpz_class r;
void init(const mpz_class& r, const mpz_class& z, bool isBLS12 = false)
{
if (!Fp::squareRoot(rw, -3)) throw cybozu::Exception("GLV1:init");
rw = -(rw + 1) / 2;
this->r = r;
rBitSize = gmp::getBitSize(r);
rBitSize = (rBitSize + fp::UnitBitSize - 1) & ~(fp::UnitBitSize - 1);// a little better size
if (isBLS12) {
/*
BLS12
L = z^4
(-z^2+1) + L = 0
1 + z^2 L = 0
*/
B[0][0] = -z * z + 1;
B[0][1] = 1;
B[1][0] = 1;
B[1][1] = z * z;
} else {
/*
BN
L = 36z^4 - 1
(6z^2+2z) - (2z+1) L = 0
(-2z-1) - (6z^2+4z+1)L = 0
*/
B[0][0] = 6 * z * z + 2 * z;
B[0][1] = -2 * z - 1;
B[1][0] = -2 * z - 1;
B[1][1] = -6 * z * z - 4 * z - 1;
}
// [v0 v1] = [r 0] * B^(-1)
v0 = ((-B[1][1]) << rBitSize) / r;
v1 = ((B[1][0]) << rBitSize) / r;
}
/*
L = lambda = p^4
L (x, y) = (rw x, y)
*/
void mulLambda(G1& Q, const G1& P) const
{
Fp::mul(Q.x, P.x, rw);
Q.y = P.y;
Q.z = P.z;
}
/*
x = a + b * lambda mod r
*/
void split(mpz_class& a, mpz_class& b, const mpz_class& x) const
{
mpz_class t;
t = (x * v0) >> rBitSize;
b = (x * v1) >> rBitSize;
a = x - (t * B[0][0] + b * B[1][0]);
b = - (t * B[0][1] + b * B[1][1]);
}
void mul(G1& Q, const G1& P, mpz_class x, bool constTime = false) const
{
typedef mcl::fp::Unit Unit;
const size_t maxUnit = 512 / 2 / mcl::fp::UnitBitSize;
const int splitN = 2;
mpz_class u[splitN];
G1 in[splitN];
G1 tbl[4];
int bitTbl[splitN]; // bit size of u[i]
Unit w[splitN][maxUnit]; // unit array of u[i]
int maxBit = 0; // max bit of u[i]
int maxN = 0;
int remainBit = 0;
x %= r;
if (x == 0) {
Q.clear();
if (constTime) goto DummyLoop;
return;
}
if (x < 0) {
x += r;
}
split(u[0], u[1], x);
in[0] = P;
mulLambda(in[1], in[0]);
for (int i = 0; i < splitN; i++) {
if (u[i] < 0) {
u[i] = -u[i];
G1::neg(in[i], in[i]);
}
in[i].normalize();
}
#if 0
G1::mulGeneric(in[0], in[0], u[0]);
G1::mulGeneric(in[1], in[1], u[1]);
G1::add(Q, in[0], in[1]);
return;
#else
tbl[0] = in[0]; // dummy
tbl[1] = in[0];
tbl[2] = in[1];
G1::add(tbl[3], in[0], in[1]);
tbl[3].normalize();
for (int i = 0; i < splitN; i++) {
mcl::gmp::getArray(w[i], maxUnit, u[i]);
bitTbl[i] = (int)mcl::gmp::getBitSize(u[i]);
maxBit = std::max(maxBit, bitTbl[i]);
}
assert(maxBit > 0);
maxBit--;
/*
maxBit = maxN * UnitBitSize + remainBit
0 < remainBit <= UnitBitSize
*/
maxN = maxBit / mcl::fp::UnitBitSize;
remainBit = maxBit % mcl::fp::UnitBitSize;
remainBit++;
Q.clear();
for (int i = maxN; i >= 0; i--) {
for (int j = remainBit - 1; j >= 0; j--) {
G1::dbl(Q, Q);
uint32_t b0 = (w[0][i] >> j) & 1;
uint32_t b1 = (w[1][i] >> j) & 1;
uint32_t c = b1 * 2 + b0;
if (c == 0) {
if (constTime) tbl[0] += tbl[1];
} else {
Q += tbl[c];
}
}
remainBit = (int)mcl::fp::UnitBitSize;
}
#endif
DummyLoop:
if (!constTime) return;
const int limitBit = (int)rBitSize / splitN;
G1 D = tbl[0];
for (int i = maxBit + 1; i < limitBit; i++) {
G1::dbl(D, D);
D += tbl[0];
}
}
};
/*
GLV method for G2 and GT on BN/BLS12
*/
struct GLV2 {
size_t rBitSize;
mpz_class B[4][4];
mpz_class r;
mpz_class v[4];
mpz_class z;
mpz_class abs_z;
bool isBLS12;
GLV2() : rBitSize(0), isBLS12(false) {}
void init(const mpz_class& r, const mpz_class& z, bool isBLS12 = false)
{
this->r = r;
this->z = z;
this->abs_z = z < 0 ? -z : z;
this->isBLS12 = isBLS12;
rBitSize = mcl::gmp::getBitSize(r);
rBitSize = (rBitSize + mcl::fp::UnitBitSize - 1) & ~(mcl::fp::UnitBitSize - 1);// a little better size
mpz_class z2p1 = z * 2 + 1;
B[0][0] = z + 1;
B[0][1] = z;
B[0][2] = z;
B[0][3] = -2 * z;
B[1][0] = z2p1;
B[1][1] = -z;
B[1][2] = -(z + 1);
B[1][3] = -z;
B[2][0] = 2 * z;
B[2][1] = z2p1;
B[2][2] = z2p1;
B[2][3] = z2p1;
B[3][0] = z - 1;
B[3][1] = 2 * z2p1;
B[3][2] = -2 * z + 1;
B[3][3] = z - 1;
/*
v[] = [r 0 0 0] * B^(-1) = [2z^2+3z+1, 12z^3+8z^2+z, 6z^3+4z^2+z, -(2z+1)]
*/
v[0] = ((1 + z * (3 + z * 2)) << rBitSize) / r;
v[1] = ((z * (1 + z * (8 + z * 12))) << rBitSize) / r;
v[2] = ((z * (1 + z * (4 + z * 6))) << rBitSize) / r;
v[3] = -((z * (1 + z * 2)) << rBitSize) / r;
}
/*
u[] = [x, 0, 0, 0] - v[] * x * B
*/
void split(mpz_class u[4], const mpz_class& x) const
{
if (isBLS12) {
/*
Frob(P) = zP
x = u[0] + u[1] z + u[2] z^2 + u[3] z^3
*/
bool isNeg = false;
mpz_class t = x;
if (t < 0) {
t = -t;
isNeg = true;
}
for (int i = 0; i < 4; i++) {
// t = t / abs_z, u[i] = t % abs_z
mcl::gmp::divmod(t, u[i], t, abs_z);
if (((z < 0) && (i & 1)) ^ isNeg) {
u[i] = -u[i];
}
}
return;
}
// BN
mpz_class t[4];
for (int i = 0; i < 4; i++) {
t[i] = (x * v[i]) >> rBitSize;
}
for (int i = 0; i < 4; i++) {
u[i] = (i == 0) ? x : 0;
for (int j = 0; j < 4; j++) {
u[i] -= t[j] * B[j][i];
}
}
}
template<class T>
void mul(T& Q, const T& P, mpz_class x, bool constTime = false) const
{
#if 0 // #ifndef NDEBUG
{
T R;
T::mulGeneric(R, P, r);
assert(R.isZero());
}
#endif
typedef mcl::fp::Unit Unit;
const size_t maxUnit = 512 / 2 / mcl::fp::UnitBitSize;
const int splitN = 4;
mpz_class u[splitN];
T in[splitN];
T tbl[16];
int bitTbl[splitN]; // bit size of u[i]
Unit w[splitN][maxUnit]; // unit array of u[i]
int maxBit = 0; // max bit of u[i]
int maxN = 0;
int remainBit = 0;
x %= r;
if (x == 0) {
Q.clear();
if (constTime) goto DummyLoop;
return;
}
if (x < 0) {
x += r;
}
split(u, x);
in[0] = P;
Frobenius(in[1], in[0]);
Frobenius(in[2], in[1]);
Frobenius(in[3], in[2]);
for (int i = 0; i < splitN; i++) {
if (u[i] < 0) {
u[i] = -u[i];
T::neg(in[i], in[i]);
}
// in[i].normalize(); // slow
}
#if 0
for (int i = 0; i < splitN; i++) {
T::mulGeneric(in[i], in[i], u[i]);
}
T::add(Q, in[0], in[1]);
Q += in[2];
Q += in[3];
return;
#else
tbl[0] = in[0];
for (size_t i = 1; i < 16; i++) {
tbl[i].clear();
if (i & 1) {
tbl[i] += in[0];
}
if (i & 2) {
tbl[i] += in[1];
}
if (i & 4) {
tbl[i] += in[2];
}
if (i & 8) {
tbl[i] += in[3];
}
// tbl[i].normalize();
}
for (int i = 0; i < splitN; i++) {
mcl::gmp::getArray(w[i], maxUnit, u[i]);
bitTbl[i] = (int)mcl::gmp::getBitSize(u[i]);
maxBit = std::max(maxBit, bitTbl[i]);
}
maxBit--;
/*
maxBit = maxN * UnitBitSize + remainBit
0 < remainBit <= UnitBitSize
*/
maxN = maxBit / mcl::fp::UnitBitSize;
remainBit = maxBit % mcl::fp::UnitBitSize;
remainBit++;
Q.clear();
for (int i = maxN; i >= 0; i--) {
for (int j = remainBit - 1; j >= 0; j--) {
T::dbl(Q, Q);
uint32_t b0 = (w[0][i] >> j) & 1;
uint32_t b1 = (w[1][i] >> j) & 1;
uint32_t b2 = (w[2][i] >> j) & 1;
uint32_t b3 = (w[3][i] >> j) & 1;
uint32_t c = b3 * 8 + b2 * 4 + b1 * 2 + b0;
if (c == 0) {
if (constTime) tbl[0] += tbl[1];
} else {
Q += tbl[c];
}
}
remainBit = (int)mcl::fp::UnitBitSize;
}
#endif
DummyLoop:
if (!constTime) return;
const int limitBit = (int)rBitSize / splitN;
T D = tbl[0];
for (int i = maxBit + 1; i < limitBit; i++) {
T::dbl(D, D);
D += tbl[0];
}
}
void pow(Fp12& z, const Fp12& x, mpz_class y, bool constTime = false) const
{
typedef GroupMtoA<Fp12> AG; // as additive group
AG& _z = static_cast<AG&>(z);
const AG& _x = static_cast<const AG&>(x);
mul(_z, _x, y, constTime);
}
};
struct Param {
CurveParam cp;
mpz_class z;
mpz_class abs_z;
bool isNegative;
bool isBLS12;
mpz_class p;
mpz_class r;
local::MapTo mapTo;
local::GLV1 glv1;
local::GLV2 glv2;
// for G2 Frobenius
Fp2 g2;
Fp2 g3;
/*
Dtype twist
(x', y') = phi(x, y) = (x/w^2, y/w^3)
y^2 = x^3 + b
=> (y'w^3)^2 = (x'w^2)^3 + b
=> y'^2 = x'^3 + b / w^6 ; w^6 = xi
=> y'^2 = x'^3 + twist_b;
*/
Fp2 twist_b;
local::TwistBtype twist_b_type;
/*
mpz_class exp_c0;
mpz_class exp_c1;
mpz_class exp_c2;
mpz_class exp_c3;
*/
// Loop parameter for the Miller loop part of opt. ate pairing.
local::SignVec siTbl;
size_t precomputedQcoeffSize;
bool useNAF;
local::SignVec zReplTbl;
void init(int *pret, const mcl::CurveParam& cp, fp::Mode mode)
{
this->cp = cp;
isBLS12 = cp.curveType == MCL_BLS12_381;
z = mpz_class(cp.z);
isNegative = z < 0;
if (isNegative) {
abs_z = -z;
} else {
abs_z = z;
}
if (isBLS12) {
mpz_class z2 = z * z;
mpz_class z4 = z2 * z2;
r = z4 - z2 + 1;
p = z - 1;
p = p * p * r / 3 + z;
} else {
const int pCoff[] = { 1, 6, 24, 36, 36 };
const int rCoff[] = { 1, 6, 18, 36, 36 };
p = local::evalPoly(z, pCoff);
assert((p % 6) == 1);
r = local::evalPoly(z, rCoff);
}
Fp::init(pret, p, mode);
if (*pret < 0) return;
Fr::init(pret, r, mode);
if (*pret < 0) return;
Fp2::init(cp.xi_a);
Fp2 xi(cp.xi_a, 1);
g2 = Fp2::get_gTbl()[0];
g3 = Fp2::get_gTbl()[3];
if (cp.isMtype) {
Fp2::inv(g2, g2);
Fp2::inv(g3, g3);
}
if (cp.isMtype) {
twist_b = Fp2(cp.b) * xi;
} else {
twist_b = Fp2(cp.b) / xi;
}
if (twist_b == Fp2(1, -1)) {
twist_b_type = tb_1m1i;
} else if (twist_b == Fp2(1, -2)) {
twist_b_type = tb_1m2i;
} else {
twist_b_type = tb_generic;
}
G1::init(0, cp.b, mcl::ec::Proj);
if (isBLS12) {
G1::setOrder(r);
}
G2::init(0, twist_b, mcl::ec::Proj);
G2::setOrder(r);
const mpz_class largest_c = isBLS12 ? abs_z : gmp::abs(z * 6 + 2);
useNAF = gmp::getNAF(siTbl, largest_c);
precomputedQcoeffSize = local::getPrecomputeQcoeffSize(siTbl);
gmp::getNAF(zReplTbl, gmp::abs(z));
/*
if (isBLS12) {
mpz_class z2 = z * z;
mpz_class z3 = z2 * z;
mpz_class z4 = z3 * z;
mpz_class z5 = z4 * z;
exp_c0 = z5 - 2 * z4 + 2 * z2 - z + 3;
exp_c1 = z4 - 2 * z3 + 2 * z - 1;
exp_c2 = z3 - 2 * z2 + z;
exp_c3 = z2 - 2 * z + 1;
} else {
exp_c0 = -2 + z * (-18 + z * (-30 - 36 * z));
exp_c1 = 1 + z * (-12 + z * (-18 - 36 * z));
exp_c2 = 6 * z * z + 1;
}
*/
if (isBLS12) {
mapTo.init(0, z, false);
} else {
mapTo.init(2 * p - r, z, true);
}
glv1.init(r, z, isBLS12);
glv2.init(r, z, isBLS12);
*pret = 0;
}
void init(const mcl::CurveParam& cp, fp::Mode mode)
{
int ret;
init(&ret, cp, mode);
if (ret < 0) throw cybozu::Exception("Param:init") << ret;
}
};
template<size_t dummyImpl = 0>
struct StaticVar {
static local::Param param;
};
template<size_t dummyImpl>
local::Param StaticVar<dummyImpl>::param;
} // mcl::bn::local
namespace BN {
static const local::Param& param = local::StaticVar<>::param;
} // mcl::bn::BN
namespace local {
inline void mulArrayGLV1(G1& z, const G1& x, const mcl::fp::Unit *y, size_t yn, bool isNegative, bool constTime)
{
mpz_class s;
mcl::gmp::setArray(s, y, yn);
if (isNegative) s = -s;
BN::param.glv1.mul(z, x, s, constTime);
}
inline void mulArrayGLV2(G2& z, const G2& x, const mcl::fp::Unit *y, size_t yn, bool isNegative, bool constTime)
{
mpz_class s;
mcl::gmp::setArray(s, y, yn);
if (isNegative) s = -s;
BN::param.glv2.mul(z, x, s, constTime);
}
inline void powArrayGLV2(Fp12& z, const Fp12& x, const mcl::fp::Unit *y, size_t yn, bool isNegative, bool constTime)
{
mpz_class s;
mcl::gmp::setArray(s, y, yn);
if (isNegative) s = -s;
BN::param.glv2.pow(z, x, s, constTime);
}
/*
Faster Squaring in the Cyclotomic Subgroup of Sixth Degree Extensions
Robert Granger, Michael Scott
*/
inline void sqrFp4(Fp2& z0, Fp2& z1, const Fp2& x0, const Fp2& x1)
{
#if 1
Fp2Dbl T0, T1, T2;
Fp2Dbl::sqrPre(T0, x0);
Fp2Dbl::sqrPre(T1, x1);
Fp2Dbl::mul_xi(T2, T1);
Fp2Dbl::add(T2, T2, T0);
Fp2::add(z1, x0, x1);
Fp2Dbl::mod(z0, T2);
Fp2Dbl::sqrPre(T2, z1);
Fp2Dbl::sub(T2, T2, T0);
Fp2Dbl::sub(T2, T2, T1);
Fp2Dbl::mod(z1, T2);
#else
Fp2 t0, t1, t2;
Fp2::sqr(t0, x0);
Fp2::sqr(t1, x1);
Fp2::mul_xi(z0, t1);
z0 += t0;
Fp2::add(z1, x0, x1);
Fp2::sqr(z1, z1);
z1 -= t0;
z1 -= t1;
#endif
}
inline void fasterSqr(Fp12& y, const Fp12& x)
{
#if 0
Fp12::sqr(y, x);
#else
const Fp2& x0(x.a.a);
const Fp2& x4(x.a.b);
const Fp2& x3(x.a.c);
const Fp2& x2(x.b.a);
const Fp2& x1(x.b.b);
const Fp2& x5(x.b.c);
Fp2& y0(y.a.a);
Fp2& y4(y.a.b);
Fp2& y3(y.a.c);
Fp2& y2(y.b.a);
Fp2& y1(y.b.b);
Fp2& y5(y.b.c);
Fp2 t0, t1;
sqrFp4(t0, t1, x0, x1);
Fp2::sub(y0, t0, x0);
y0 += y0;
y0 += t0;
Fp2::add(y1, t1, x1);
y1 += y1;
y1 += t1;
Fp2 t2, t3;
sqrFp4(t0, t1, x2, x3);
sqrFp4(t2, t3, x4, x5);
Fp2::sub(y4, t0, x4);
y4 += y4;
y4 += t0;
Fp2::add(y5, t1, x5);
y5 += y5;
y5 += t1;
Fp2::mul_xi(t0, t3);
Fp2::add(y2, t0, x2);
y2 += y2;
y2 += t0;
Fp2::sub(y3, t2, x3);
y3 += y3;
y3 += t2;
#endif
}
/*
y = x^z if z > 0
= unitaryInv(x^(-z)) if z < 0
*/
inline void pow_z(Fp12& y, const Fp12& x)
{
#if 1
if (BN::param.cp.curveType == MCL_BN254) {
Compress::fixed_power(y, x);
} else {
Fp12 orgX = x;
y = x;
Fp12 conj;
conj.a = x.a;
Fp6::neg(conj.b, x.b);
for (size_t i = 1; i < BN::param.zReplTbl.size(); i++) {
fasterSqr(y, y);
if (BN::param.zReplTbl[i] > 0) {
y *= orgX;
} else if (BN::param.zReplTbl[i] < 0) {
y *= conj;
}
}
}
#else
Fp12::pow(y, x, param.abs_z);
#endif
if (BN::param.isNegative) {
Fp12::unitaryInv(y, y);
}
}
inline void mul_twist_b(Fp2& y, const Fp2& x)
{
switch (BN::param.twist_b_type) {
case local::tb_1m1i:
/*
b / xi = 1 - 1i
(a + bi)(1 - 1i) = (a + b) + (b - a)i
*/
{
Fp t;
Fp::add(t, x.a, x.b);
Fp::sub(y.b, x.b, x.a);
y.a = t;
}
return;
case local::tb_1m2i:
/*
b / xi = 1 - 2i
(a + bi)(1 - 2i) = (a + 2b) + (b - 2a)i
*/
{
Fp t;
Fp::sub(t, x.b, x.a);
t -= x.a;
Fp::add(y.a, x.a, x.b);
y.a += x.b;
y.b = t;
}
return;
case local::tb_generic:
Fp2::mul(y, x, BN::param.twist_b);
return;
}
}
inline void dblLineWithoutP(Fp6& l, G2& Q)
{
Fp2 t0, t1, t2, t3, t4, t5;
Fp2Dbl T0, T1;
Fp2::sqr(t0, Q.z);
Fp2::mul(t4, Q.x, Q.y);
Fp2::sqr(t1, Q.y);
Fp2::add(t3, t0, t0);
Fp2::divBy2(t4, t4);
Fp2::add(t5, t0, t1);
t0 += t3;
mul_twist_b(t2, t0);
Fp2::sqr(t0, Q.x);
Fp2::add(t3, t2, t2);
t3 += t2;
Fp2::sub(Q.x, t1, t3);
t3 += t1;
Q.x *= t4;
Fp2::divBy2(t3, t3);
Fp2Dbl::sqrPre(T0, t3);
Fp2Dbl::sqrPre(T1, t2);
Fp2Dbl::sub(T0, T0, T1);
Fp2Dbl::add(T1, T1, T1);
Fp2Dbl::sub(T0, T0, T1);
Fp2::add(t3, Q.y, Q.z);
Fp2Dbl::mod(Q.y, T0);
Fp2::sqr(t3, t3);
t3 -= t5;
Fp2::mul(Q.z, t1, t3);
Fp2::sub(l.a, t2, t1);
l.c = t0;
l.b = t3;
}
inline void addLineWithoutP(Fp6& l, G2& R, const G2& Q)
{
Fp2 t1, t2, t3, t4;
Fp2Dbl T1, T2;
Fp2::mul(t1, R.z, Q.x);
Fp2::mul(t2, R.z, Q.y);
Fp2::sub(t1, R.x, t1);
Fp2::sub(t2, R.y, t2);
Fp2::sqr(t3, t1);
Fp2::mul(R.x, t3, R.x);
Fp2::sqr(t4, t2);
t3 *= t1;
t4 *= R.z;
t4 += t3;
t4 -= R.x;
t4 -= R.x;
R.x -= t4;
Fp2Dbl::mulPre(T1, t2, R.x);
Fp2Dbl::mulPre(T2, t3, R.y);
Fp2Dbl::sub(T2, T1, T2);
Fp2Dbl::mod(R.y, T2);
Fp2::mul(R.x, t1, t4);
Fp2::mul(R.z, t3, R.z);
Fp2::neg(l.c, t2);
Fp2Dbl::mulPre(T1, t2, Q.x);
Fp2Dbl::mulPre(T2, t1, Q.y);
Fp2Dbl::sub(T1, T1, T2);
l.b = t1;
Fp2Dbl::mod(l.a, T1);
}
inline void dblLine(Fp6& l, G2& Q, const G1& P)
{
dblLineWithoutP(l, Q);
local::updateLine(l, P);
}
inline void addLine(Fp6& l, G2& R, const G2& Q, const G1& P)
{
addLineWithoutP(l, R, Q);
local::updateLine(l, P);
}
inline void mulFp6cb_by_G1xy(Fp6& y, const Fp6& x, const G1& P)
{
assert(P.isNormalized());
if (&y != &x) y.a = x.a;
Fp2::mulFp(y.c, x.c, P.x);
Fp2::mulFp(y.b, x.b, P.y);
}
/*
x = a + bv + cv^2
y = (y0, y4, y2) -> (y0, 0, y2, 0, y4, 0)
z = xy = (a + bv + cv^2)(d + ev)
= (ad + ce xi) + ((a + b)(d + e) - ad - be)v + (be + cd)v^2
*/
inline void Fp6mul_01(Fp6& z, const Fp6& x, const Fp2& d, const Fp2& e)
{
const Fp2& a = x.a;
const Fp2& b = x.b;
const Fp2& c = x.c;
Fp2 t0, t1;
Fp2Dbl AD, CE, BE, CD, T;
Fp2Dbl::mulPre(AD, a, d);
Fp2Dbl::mulPre(CE, c, e);
Fp2Dbl::mulPre(BE, b, e);
Fp2Dbl::mulPre(CD, c, d);
Fp2::add(t0, a, b);
Fp2::add(t1, d, e);
Fp2Dbl::mulPre(T, t0, t1);
T -= AD;
T -= BE;
Fp2Dbl::mod(z.b, T);
Fp2Dbl::mul_xi(CE, CE);
AD += CE;
Fp2Dbl::mod(z.a, AD);
BE += CD;
Fp2Dbl::mod(z.c, BE);
}
/*
input
z = (z0 + z1v + z2v^2) + (z3 + z4v + z5v^2)w = Z0 + Z1w
0 3 4
x = (a, b, c) -> (b, 0, 0, c, a, 0) = X0 + X1w
X0 = b = (b, 0, 0)
X1 = c + av = (c, a, 0)
w^2 = v, v^3 = xi
output
z <- zx = (Z0X0 + Z1X1v) + ((Z0 + Z1)(X0 + X1) - Z0X0 - Z1X1)w
Z0X0 = Z0 b
Z1X1 = Z1 (c, a, 0)
(Z0 + Z1)(X0 + X1) = (Z0 + Z1) (b + c, a, 0)
*/
inline void mul_403(Fp12& z, const Fp6& x)
{
const Fp2& a = x.a;
const Fp2& b = x.b;
const Fp2& c = x.c;
#if 1
Fp6& z0 = z.a;
Fp6& z1 = z.b;
Fp6 z0x0, z1x1, t0;
Fp2 t1;
Fp2::add(t1, x.b, c);
Fp6::add(t0, z0, z1);
Fp2::mul(z0x0.a, z0.a, b);
Fp2::mul(z0x0.b, z0.b, b);
Fp2::mul(z0x0.c, z0.c, b);
Fp6mul_01(z1x1, z1, c, a);
Fp6mul_01(t0, t0, t1, a);
Fp6::sub(z.b, t0, z0x0);
z.b -= z1x1;
// a + bv + cv^2 = cxi + av + bv^2
Fp2::mul_xi(z1x1.c, z1x1.c);
Fp2::add(z.a.a, z0x0.a, z1x1.c);
Fp2::add(z.a.b, z0x0.b, z1x1.a);
Fp2::add(z.a.c, z0x0.c, z1x1.b);
#else
Fp2& z0 = z.a.a;
Fp2& z1 = z.a.b;
Fp2& z2 = z.a.c;
Fp2& z3 = z.b.a;
Fp2& z4 = z.b.b;
Fp2& z5 = z.b.c;
Fp2Dbl Z0B, Z1B, Z2B, Z3C, Z4C, Z5C;
Fp2Dbl T0, T1, T2, T3, T4, T5;
Fp2 bc, t;
Fp2::addPre(bc, b, c);
Fp2::addPre(t, z5, z2);
Fp2Dbl::mulPre(T5, t, bc);
Fp2Dbl::mulPre(Z5C, z5, c);
Fp2Dbl::mulPre(Z2B, z2, b);
Fp2Dbl::sub(T5, T5, Z5C);
Fp2Dbl::sub(T5, T5, Z2B);
Fp2Dbl::mulPre(T0, z1, a);
T5 += T0;
Fp2::addPre(t, z4, z1);
Fp2Dbl::mulPre(T4, t, bc);
Fp2Dbl::mulPre(Z4C, z4, c);
Fp2Dbl::mulPre(Z1B, z1, b);
Fp2Dbl::sub(T4, T4, Z4C);
Fp2Dbl::sub(T4, T4, Z1B);
Fp2Dbl::mulPre(T0, z0, a);
T4 += T0;
Fp2::addPre(t, z3, z0);
Fp2Dbl::mulPre(T3, t, bc);
Fp2Dbl::mulPre(Z3C, z3, c);
Fp2Dbl::mulPre(Z0B, z0, b);
Fp2Dbl::sub(T3, T3, Z3C);
Fp2Dbl::sub(T3, T3, Z0B);
Fp2::mul_xi(t, z2);
Fp2Dbl::mulPre(T0, t, a);
T3 += T0;
Fp2Dbl::mulPre(T2, z3, a);
T2 += Z2B;
T2 += Z4C;
Fp2::mul_xi(t, z5);
Fp2Dbl::mulPre(T1, t, a);
T1 += Z1B;
T1 += Z3C;
Fp2Dbl::mulPre(T0, z4, a);
T0 += Z5C;
Fp2Dbl::mul_xi(T0, T0);
T0 += Z0B;
Fp2Dbl::mod(z0, T0);
Fp2Dbl::mod(z1, T1);
Fp2Dbl::mod(z2, T2);
Fp2Dbl::mod(z3, T3);
Fp2Dbl::mod(z4, T4);
Fp2Dbl::mod(z5, T5);
#endif
}
/*
input
z = (z0 + z1v + z2v^2) + (z3 + z4v + z5v^2)w = Z0 + Z1w
0 1 4
x = (a, b, c) -> (a, c, 0, 0, b, 0) = X0 + X1w
X0 = (a, c, 0)
X1 = (0, b, 0)
w^2 = v, v^3 = xi
output
z <- zx = (Z0X0 + Z1X1v) + ((Z0 + Z1)(X0 + X1) - Z0X0 - Z1X1)w
Z0X0 = Z0 (a, c, 0)
Z1X1 = Z1 (0, b, 0) = Z1 bv
(Z0 + Z1)(X0 + X1) = (Z0 + Z1) (a, b + c, 0)
(a + bv + cv^2)v = c xi + av + bv^2
*/
inline void mul_041(Fp12& z, const Fp6& x)
{
const Fp2& a = x.a;
const Fp2& b = x.b;
const Fp2& c = x.c;
Fp6& z0 = z.a;
Fp6& z1 = z.b;
Fp6 z0x0, z1x1, t0;
Fp2 t1;
Fp2::mul(z1x1.a, z1.c, b);
Fp2::mul_xi(z1x1.a, z1x1.a);
Fp2::mul(z1x1.b, z1.a, b);
Fp2::mul(z1x1.c, z1.b, b);
Fp2::add(t1, x.b, c);
Fp6::add(t0, z0, z1);
Fp6mul_01(z0x0, z0, a, c);
Fp6mul_01(t0, t0, a, t1);
Fp6::sub(z.b, t0, z0x0);
z.b -= z1x1;
// a + bv + cv^2 = cxi + av + bv^2
Fp2::mul_xi(z1x1.c, z1x1.c);
Fp2::add(z.a.a, z0x0.a, z1x1.c);
Fp2::add(z.a.b, z0x0.b, z1x1.a);
Fp2::add(z.a.c, z0x0.c, z1x1.b);
}
inline void mulSparse(Fp12& z, const Fp6& x)
{
if (BN::param.cp.isMtype) {
mul_041(z, x);
} else {
mul_403(z, x);
}
}
inline void convertFp6toFp12(Fp12& y, const Fp6& x)
{
y.clear();
if (BN::param.cp.isMtype) {
// (a, b, c) -> (a, c, 0, 0, b, 0)
y.a.a = x.a;
y.b.b = x.b;
y.a.b = x.c;
} else {
// (a, b, c) -> (b, 0, 0, c, a, 0)
y.b.b = x.a;
y.a.a = x.b;
y.b.a = x.c;
}
}
inline void mulSparse2(Fp12& z, const Fp6& x, const Fp6& y)
{
convertFp6toFp12(z, x);
mulSparse(z, y);
}
inline void mapToCyclotomic(Fp12& y, const Fp12& x)
{
Fp12 z;
Fp12::Frobenius2(z, x); // z = x^(p^2)
z *= x; // x^(p^2 + 1)
Fp12::inv(y, z);
Fp6::neg(z.b, z.b); // z^(p^6) = conjugate of z
y *= z;
}
/*
Implementing Pairings at the 192-bit Security Level
D.F.Aranha, L.F.Castaneda, E.Knapp, A.Menezes, F.R.Henriquez
Section 4
*/
inline void expHardPartBLS12(Fp12& y, const Fp12& x)
{
#if 0
const mpz_class& p = param.p;
mpz_class p2 = p * p;
mpz_class p4 = p2 * p2;
Fp12::pow(y, x, (p4 - p2 + 1) / param.r * 3);
return;
#endif
#if 1
Fp12 a0, a1, a2, a3, a4, a5, a6, a7;
Fp12::unitaryInv(a0, x); // a0 = x^-1
fasterSqr(a1, a0); // x^-2
pow_z(a2, x); // x^z
fasterSqr(a3, a2); // x^2z
a1 *= a2; // a1 = x^(z-2)
pow_z(a7, a1); // a7 = x^(z^2-2z)
pow_z(a4, a7); // a4 = x^(z^3-2z^2)
pow_z(a5, a4); // a5 = x^(z^4-2z^3)
a3 *= a5; // a3 = x^(z^4-2z^3+2z)
pow_z(a6, a3); // a6 = x^(z^5-2z^4+2z^2)
Fp12::unitaryInv(a1, a1); // x^(2-z)
a1 *= a6; // x^(z^5-2z^4+2z^2-z+2)
a1 *= x; // x^(z^5-2z^4+2z^2-z+3) = x^c0
a3 *= a0; // x^(z^4-2z^3-1) = x^c1
Fp12::Frobenius(a3, a3); // x^(c1 p)
a1 *= a3; // x^(c0 + c1 p)
a4 *= a2; // x^(z^3-2z^2+z) = x^c2
Fp12::Frobenius2(a4, a4); // x^(c2 p^2)
a1 *= a4; // x^(c0 + c1 p + c2 p^2)
a7 *= x; // x^(z^2-2z+1) = x^c3
Fp12::Frobenius3(y, a7);
y *= a1;
#else
Fp12 t1, t2, t3;
Fp12::Frobenius(t1, x);
Fp12::Frobenius(t2, t1);
Fp12::Frobenius(t3, t2);
Fp12::pow(t1, t1, param.exp_c1);
Fp12::pow(t2, t2, param.exp_c2);
Fp12::pow(t3, t3, param.exp_c3);
Fp12::pow(y, x, param.exp_c0);
y *= t1;
y *= t2;
y *= t3;
#endif
}
/*
Faster Hashing to G2
Laura Fuentes-Castaneda, Edward Knapp, Francisco Rodriguez-Henriquez
section 4.1
y = x^(d 2z(6z^2 + 3z + 1)) where
p = p(z) = 36z^4 + 36z^3 + 24z^2 + 6z + 1
r = r(z) = 36z^4 + 36z^3 + 18z^2 + 6z + 1
d = (p^4 - p^2 + 1) / r
d1 = d 2z(6z^2 + 3z + 1)
= c0 + c1 p + c2 p^2 + c3 p^3
c0 = 1 + 6z + 12z^2 + 12z^3
c1 = 4z + 6z^2 + 12z^3
c2 = 6z + 6z^2 + 12z^3
c3 = -1 + 4z + 6z^2 + 12z^3
x -> x^z -> x^2z -> x^4z -> x^6z -> x^(6z^2) -> x^(12z^2) -> x^(12z^3)
a = x^(6z) x^(6z^2) x^(12z^3)
b = a / (x^2z)
x^d1 = (a x^(6z^2) x) b^p a^(p^2) (b / x)^(p^3)
*/
inline void expHardPartBN(Fp12& y, const Fp12& x)
{
#if 0
const mpz_class& p = param.p;
mpz_class p2 = p * p;
mpz_class p4 = p2 * p2;
Fp12::pow(y, x, (p4 - p2 + 1) / param.r);
return;
#endif
#if 1
Fp12 a, b;
Fp12 a2, a3;
pow_z(b, x); // x^z
fasterSqr(b, b); // x^2z
fasterSqr(a, b); // x^4z
a *= b; // x^6z
pow_z(a2, a); // x^(6z^2)
a *= a2;
fasterSqr(a3, a2); // x^(12z^2)
pow_z(a3, a3); // x^(12z^3)
a *= a3;
Fp12::unitaryInv(b, b);
b *= a;
a2 *= a;
Fp12::Frobenius2(a, a);
a *= a2;
a *= x;
Fp12::unitaryInv(y, x);
y *= b;
Fp12::Frobenius(b, b);
a *= b;
Fp12::Frobenius3(y, y);
y *= a;
#else
Fp12 t1, t2, t3;
Fp12::Frobenius(t1, x);
Fp12::Frobenius(t2, t1);
Fp12::Frobenius(t3, t2);
Fp12::pow(t1, t1, param.exp_c1);
Fp12::pow(t2, t2, param.exp_c2);
Fp12::pow(y, x, param.exp_c0);
y *= t1;
y *= t2;
y *= t3;
#endif
}
/*
remark : returned value is NOT on a curve
*/
inline G1 makeAdjP(const G1& P)
{
G1 adjP;
Fp::add(adjP.x, P.x, P.x);
adjP.x += P.x;
Fp::neg(adjP.y, P.y);
adjP.z = 1;
return adjP;
}
} // mcl::bn::local
/*
y = x^((p^12 - 1) / r)
(p^12 - 1) / r = (p^2 + 1) (p^6 - 1) (p^4 - p^2 + 1)/r
(a + bw)^(p^6) = a - bw in Fp12
(p^4 - p^2 + 1)/r = c0 + c1 p + c2 p^2 + p^3
*/
inline void finalExp(Fp12& y, const Fp12& x)
{
#if 1
mapToCyclotomic(y, x);
#else
const mpz_class& p = param.p;
mpz_class p2 = p * p;
mpz_class p4 = p2 * p2;
Fp12::pow(y, x, p2 + 1);
Fp12::pow(y, y, p4 * p2 - 1);
#endif
if (BN::param.isBLS12) {
expHardPartBLS12(y, y);
} else {
expHardPartBN(y, y);
}
}
inline void millerLoop(Fp12& f, const G1& P_, const G2& Q_)
{
G1 P(P_);
G2 Q(Q_);
P.normalize();
Q.normalize();
if (Q.isZero()) {
f = 1;
return;
}
assert(BN::param.siTbl[1] == 1);
G2 T = Q;
G2 negQ;
if (BN::param.useNAF) {
G2::neg(negQ, Q);
}
Fp6 d, e, l;
d = e = l = 1;
G1 adjP = makeAdjP(P);
dblLine(d, T, adjP);
addLine(l, T, Q, P);
mulSparse2(f, d, l);
for (size_t i = 2; i < BN::param.siTbl.size(); i++) {
dblLine(l, T, adjP);
Fp12::sqr(f, f);
mulSparse(f, l);
if (BN::param.siTbl[i]) {
if (BN::param.siTbl[i] > 0) {
addLine(l, T, Q, P);
} else {
addLine(l, T, negQ, P);
}
mulSparse(f, l);
}
}
if (BN::param.z < 0) {
G2::neg(T, T);
Fp6::neg(f.b, f.b);
}
if (BN::param.isBLS12) return;
G2 Q1, Q2;
Frobenius(Q1, Q);
Frobenius(Q2, Q1);
G2::neg(Q2, Q2);
addLine(d, T, Q1, P);
addLine(e, T, Q2, P);
Fp12 ft;
mulSparse2(ft, d, e);
f *= ft;
}
inline void pairing(Fp12& f, const G1& P, const G2& Q)
{
millerLoop(f, P, Q);
finalExp(f, f);
}
/*
allocate param.precomputedQcoeffSize elements of Fp6 for Qcoeff
*/
inline void precomputeG2(Fp6 *Qcoeff, const G2& Q_)
{
size_t idx = 0;
G2 Q(Q_);
Q.normalize();
if (Q.isZero()) {
for (size_t i = 0; i < BN::param.precomputedQcoeffSize; i++) {
Qcoeff[i] = 1;
}
return;
}
G2 T = Q;
G2 negQ;
if (BN::param.useNAF) {
G2::neg(negQ, Q);
}
assert(BN::param.siTbl[1] == 1);
dblLineWithoutP(Qcoeff[idx++], T);
addLineWithoutP(Qcoeff[idx++], T, Q);
for (size_t i = 2; i < BN::param.siTbl.size(); i++) {
dblLineWithoutP(Qcoeff[idx++], T);
if (BN::param.siTbl[i]) {
if (BN::param.siTbl[i] > 0) {
addLineWithoutP(Qcoeff[idx++], T, Q);
} else {
addLineWithoutP(Qcoeff[idx++], T, negQ);
}
}
}
if (BN::param.z < 0) {
G2::neg(T, T);
}
if (BN::param.isBLS12) return;
G2 Q1, Q2;
Frobenius(Q1, Q);
Frobenius(Q2, Q1);
G2::neg(Q2, Q2);
addLineWithoutP(Qcoeff[idx++], T, Q1);
addLineWithoutP(Qcoeff[idx++], T, Q2);
assert(idx == BN::param.precomputedQcoeffSize);
}
/*
millerLoop(e, P, Q) is same as the following
std::vector<Fp6> Qcoeff;
precomputeG2(Qcoeff, Q);
precomputedMillerLoop(e, P, Qcoeff);
*/
inline void precomputeG2(std::vector<Fp6>& Qcoeff, const G2& Q)
{
Qcoeff.resize(BN::param.precomputedQcoeffSize);
precomputeG2(Qcoeff.data(), Q);
}
inline bool precomputeG2(mcl::Vector<Fp6>& Qcoeff, const G2& Q)
{
bool b = Qcoeff.resize(BN::param.precomputedQcoeffSize);
if (!b) return false;
precomputeG2(Qcoeff.data(), Q);
return true;
}
inline void precomputedMillerLoop(Fp12& f, const G1& P_, const Fp6* Qcoeff)
{
G1 P(P_);
P.normalize();
G1 adjP = makeAdjP(P);
size_t idx = 0;
Fp6 d, e, l;
mulFp6cb_by_G1xy(d, Qcoeff[idx], adjP);
idx++;
mulFp6cb_by_G1xy(e, Qcoeff[idx], P);
idx++;
mulSparse2(f, d, e);
for (size_t i = 2; i < BN::param.siTbl.size(); i++) {
mulFp6cb_by_G1xy(l, Qcoeff[idx], adjP);
idx++;
Fp12::sqr(f, f);
mulSparse(f, l);
if (BN::param.siTbl[i]) {
mulFp6cb_by_G1xy(l, Qcoeff[idx], P);
idx++;
mulSparse(f, l);
}
}
if (BN::param.z < 0) {
Fp6::neg(f.b, f.b);
}
if (BN::param.isBLS12) return;
mulFp6cb_by_G1xy(d, Qcoeff[idx], P);
idx++;
mulFp6cb_by_G1xy(e, Qcoeff[idx], P);
idx++;
Fp12 ft;
mulSparse2(ft, d, e);
f *= ft;
}
inline void precomputedMillerLoop(Fp12& f, const G1& P, const std::vector<Fp6>& Qcoeff)
{
precomputedMillerLoop(f, P, Qcoeff.data());
}
inline void precomputedMillerLoop(Fp12& f, const G1& P, const mcl::Vector<Fp6>& Qcoeff)
{
precomputedMillerLoop(f, P, Qcoeff.data());
}
/*
f = MillerLoop(P1, Q1) x MillerLoop(P2, Q2)
*/
inline void precomputedMillerLoop2(Fp12& f, const G1& P1_, const Fp6* Q1coeff, const G1& P2_, const Fp6* Q2coeff)
{
G1 P1(P1_), P2(P2_);
P1.normalize();
P2.normalize();
G1 adjP1 = makeAdjP(P1);
G1 adjP2 = makeAdjP(P2);
size_t idx = 0;
Fp6 d1, d2, e1, e2, l1, l2;
mulFp6cb_by_G1xy(d1, Q1coeff[idx], adjP1);
mulFp6cb_by_G1xy(d2, Q2coeff[idx], adjP2);
idx++;
Fp12 f1, f2;
mulFp6cb_by_G1xy(e1, Q1coeff[idx], P1);
mulSparse2(f1, d1, e1);
mulFp6cb_by_G1xy(e2, Q2coeff[idx], P2);
mulSparse2(f2, d2, e2);
Fp12::mul(f, f1, f2);
idx++;
for (size_t i = 2; i < BN::param.siTbl.size(); i++) {
mulFp6cb_by_G1xy(l1, Q1coeff[idx], adjP1);
mulFp6cb_by_G1xy(l2, Q2coeff[idx], adjP2);
idx++;
Fp12::sqr(f, f);
mulSparse2(f1, l1, l2);
f *= f1;
if (BN::param.siTbl[i]) {
mulFp6cb_by_G1xy(l1, Q1coeff[idx], P1);
mulFp6cb_by_G1xy(l2, Q2coeff[idx], P2);
idx++;
mulSparse2(f1, l1, l2);
f *= f1;
}
}
if (BN::param.z < 0) {
Fp6::neg(f.b, f.b);
}
if (BN::param.isBLS12) return;
mulFp6cb_by_G1xy(d1, Q1coeff[idx], P1);
mulFp6cb_by_G1xy(d2, Q2coeff[idx], P2);
idx++;
mulFp6cb_by_G1xy(e1, Q1coeff[idx], P1);
mulFp6cb_by_G1xy(e2, Q2coeff[idx], P2);
idx++;
mulSparse2(f1, d1, e1);
mulSparse2(f2, d2, e2);
f *= f1;
f *= f2;
}
inline void precomputedMillerLoop2(Fp12& f, const G1& P1, const std::vector<Fp6>& Q1coeff, const G1& P2, const std::vector<Fp6>& Q2coeff)
{
precomputedMillerLoop2(f, P1, Q1coeff.data(), P2, Q2coeff.data());
}
inline void precomputedMillerLoop2(Fp12& f, const G1& P1, const mcl::Vector<Fp6>& Q1coeff, const G1& P2, const mcl::Vector<Fp6>& Q2coeff)
{
precomputedMillerLoop2(f, P1, Q1coeff.data(), P2, Q2coeff.data());
}
inline void mapToG1(bool *pb, G1& P, const Fp& x) { *pb = BN::param.mapTo.calcG1(P, x); }
inline void mapToG2(bool *pb, G2& P, const Fp2& x) { *pb = BN::param.mapTo.calcG2(P, x); }
inline void mapToG1(G1& P, const Fp& x)
{
bool b;
mapToG1(&b, P, x);
if (!b) throw cybozu::Exception("mapToG1:bad value") << x;
}
inline void mapToG2(G2& P, const Fp2& x)
{
bool b;
mapToG2(&b, P, x);
if (!b) throw cybozu::Exception("mapToG2:bad value") << x;
}
inline void hashAndMapToG1(G1& P, const void *buf, size_t bufSize)
{
Fp t;
t.setHashOf(buf, bufSize);
bool b;
mapToG1(&b, P, t);
// It will not happen that the hashed value is equal to special value
assert(b);
(void)b;
}
inline void hashAndMapToG2(G2& P, const void *buf, size_t bufSize)
{
Fp2 t;
t.a.setHashOf(buf, bufSize);
t.b.clear();
bool b;
mapToG2(&b, P, t);
// It will not happen that the hashed value is equal to special value
assert(b);
(void)b;
}
inline void hashAndMapToG1(G1& P, const std::string& str)
{
hashAndMapToG1(P, str.c_str(), str.size());
}
inline void hashAndMapToG2(G2& P, const std::string& str)
{
hashAndMapToG2(P, str.c_str(), str.size());
}
inline void verifyOrderG1(bool doVerify)
{
if (BN::param.isBLS12) {
G1::setOrder(doVerify ? BN::param.r : 0);
}
}
inline void verifyOrderG2(bool doVerify)
{
G2::setOrder(doVerify ? BN::param.r : 0);
}
// backward compatibility
using mcl::CurveParam;
static const CurveParam& CurveFp254BNb = BN254;
static const CurveParam& CurveFp382_1 = BN381_1;
static const CurveParam& CurveFp382_2 = BN381_2;
static const CurveParam& CurveFp462 = BN462;
static const CurveParam& CurveSNARK1 = BN_SNARK1;
/*
FrobeniusOnTwist for Dtype
p mod 6 = 1, w^6 = xi
Frob(x', y') = phi Frob phi^-1(x', y')
= phi Frob (x' w^2, y' w^3)
= phi (x'^p w^2p, y'^p w^3p)
= (F(x') w^2(p - 1), F(y') w^3(p - 1))
= (F(x') g^2, F(y') g^3)
FrobeniusOnTwist for Dtype
use (1/g) instead of g
*/
inline void Frobenius(G2& D, const G2& S)
{
Fp2::Frobenius(D.x, S.x);
Fp2::Frobenius(D.y, S.y);
Fp2::Frobenius(D.z, S.z);
D.x *= BN::param.g2;
D.y *= BN::param.g3;
}
inline void Frobenius2(G2& D, const G2& S)
{
Frobenius(D, S);
Frobenius(D, D);
}
inline void Frobenius3(G2& D, const G2& S)
{
Frobenius(D, S);
Frobenius(D, D);
Frobenius(D, D);
}
namespace BN {
using namespace mcl::bn; // backward compatibility
inline void init(int *pret, const mcl::CurveParam& cp = mcl::BN254, fp::Mode mode = fp::FP_AUTO)
{
local::StaticVar<>::param.init(pret, cp, mode);
if (*pret < 0) return;
G1::setMulArrayGLV(local::mulArrayGLV1);
G2::setMulArrayGLV(local::mulArrayGLV2);
Fp12::setPowArrayGLV(local::powArrayGLV2);
G1::setCompressedExpression();
G2::setCompressedExpression();
*pret = 0;
}
inline void init(const mcl::CurveParam& cp = mcl::BN254, fp::Mode mode = fp::FP_AUTO)
{
int ret;
init(&ret, cp, mode);
if (ret < 0) throw cybozu::Exception("BN:init") << ret;
}
} // mcl::bn::BN
inline void initPairing(int *pret, const mcl::CurveParam& cp = mcl::BN254, fp::Mode mode = fp::FP_AUTO)
{
BN::init(pret, cp, mode);
}
inline void initPairing(const mcl::CurveParam& cp = mcl::BN254, fp::Mode mode = fp::FP_AUTO)
{
int ret;
BN::init(&ret, cp, mode);
if (ret < 0) throw cybozu::Exception("bn:initPairing") << ret;
}
} } // mcl::bn