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dragonx/src/snark/libsnark/algebra/fields/fp6_3over2.tcc
2018-04-20 03:32:45 +03:00

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7.6 KiB
C++

/** @file
*****************************************************************************
Implementation of arithmetic in the finite field F[(p^2)^3].
*****************************************************************************
* @author This file is part of libsnark, developed by SCIPR Lab
* and contributors (see AUTHORS).
* @copyright MIT license (see LICENSE file)
*****************************************************************************/
#ifndef FP6_3OVER2_TCC_
#define FP6_3OVER2_TCC_
#include "algebra/fields/field_utils.hpp"
namespace libsnark {
template<mp_size_t n, const bigint<n>& modulus>
Fp2_model<n, modulus> Fp6_3over2_model<n,modulus>::mul_by_non_residue(const Fp2_model<n, modulus> &elt)
{
return Fp2_model<n, modulus>(non_residue * elt);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::zero()
{
return Fp6_3over2_model<n, modulus>(my_Fp2::zero(), my_Fp2::zero(), my_Fp2::zero());
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::one()
{
return Fp6_3over2_model<n, modulus>(my_Fp2::one(), my_Fp2::zero(), my_Fp2::zero());
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::random_element()
{
Fp6_3over2_model<n, modulus> r;
r.c0 = my_Fp2::random_element();
r.c1 = my_Fp2::random_element();
r.c2 = my_Fp2::random_element();
return r;
}
template<mp_size_t n, const bigint<n>& modulus>
bool Fp6_3over2_model<n,modulus>::operator==(const Fp6_3over2_model<n,modulus> &other) const
{
return (this->c0 == other.c0 && this->c1 == other.c1 && this->c2 == other.c2);
}
template<mp_size_t n, const bigint<n>& modulus>
bool Fp6_3over2_model<n,modulus>::operator!=(const Fp6_3over2_model<n,modulus> &other) const
{
return !(operator==(other));
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::operator+(const Fp6_3over2_model<n,modulus> &other) const
{
return Fp6_3over2_model<n,modulus>(this->c0 + other.c0,
this->c1 + other.c1,
this->c2 + other.c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::operator-(const Fp6_3over2_model<n,modulus> &other) const
{
return Fp6_3over2_model<n,modulus>(this->c0 - other.c0,
this->c1 - other.c1,
this->c2 - other.c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n, modulus> operator*(const Fp_model<n, modulus> &lhs, const Fp6_3over2_model<n, modulus> &rhs)
{
return Fp6_3over2_model<n,modulus>(lhs*rhs.c0,
lhs*rhs.c1,
lhs*rhs.c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n, modulus> operator*(const Fp2_model<n, modulus> &lhs, const Fp6_3over2_model<n, modulus> &rhs)
{
return Fp6_3over2_model<n,modulus>(lhs*rhs.c0,
lhs*rhs.c1,
lhs*rhs.c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::operator*(const Fp6_3over2_model<n,modulus> &other) const
{
/* Devegili OhEig Scott Dahab --- Multiplication and Squaring on Pairing-Friendly Fields.pdf; Section 4 (Karatsuba) */
const my_Fp2 &A = other.c0, &B = other.c1, &C = other.c2,
&a = this->c0, &b = this->c1, &c = this->c2;
const my_Fp2 aA = a*A;
const my_Fp2 bB = b*B;
const my_Fp2 cC = c*C;
return Fp6_3over2_model<n,modulus>(aA + Fp6_3over2_model<n,modulus>::mul_by_non_residue((b+c)*(B+C)-bB-cC),
(a+b)*(A+B)-aA-bB+Fp6_3over2_model<n,modulus>::mul_by_non_residue(cC),
(a+c)*(A+C)-aA+bB-cC);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::operator-() const
{
return Fp6_3over2_model<n,modulus>(-this->c0,
-this->c1,
-this->c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::squared() const
{
/* Devegili OhEig Scott Dahab --- Multiplication and Squaring on Pairing-Friendly Fields.pdf; Section 4 (CH-SQR2) */
const my_Fp2 &a = this->c0, &b = this->c1, &c = this->c2;
const my_Fp2 s0 = a.squared();
const my_Fp2 ab = a*b;
const my_Fp2 s1 = ab + ab;
const my_Fp2 s2 = (a - b + c).squared();
const my_Fp2 bc = b*c;
const my_Fp2 s3 = bc + bc;
const my_Fp2 s4 = c.squared();
return Fp6_3over2_model<n,modulus>(s0 + Fp6_3over2_model<n,modulus>::mul_by_non_residue(s3),
s1 + Fp6_3over2_model<n,modulus>::mul_by_non_residue(s4),
s1 + s2 + s3 - s0 - s4);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::inverse() const
{
/* From "High-Speed Software Implementation of the Optimal Ate Pairing over Barreto-Naehrig Curves"; Algorithm 17 */
const my_Fp2 &a = this->c0, &b = this->c1, &c = this->c2;
const my_Fp2 t0 = a.squared();
const my_Fp2 t1 = b.squared();
const my_Fp2 t2 = c.squared();
const my_Fp2 t3 = a*b;
const my_Fp2 t4 = a*c;
const my_Fp2 t5 = b*c;
const my_Fp2 c0 = t0 - Fp6_3over2_model<n,modulus>::mul_by_non_residue(t5);
const my_Fp2 c1 = Fp6_3over2_model<n,modulus>::mul_by_non_residue(t2) - t3;
const my_Fp2 c2 = t1 - t4; // typo in paper referenced above. should be "-" as per Scott, but is "*"
const my_Fp2 t6 = (a * c0 + Fp6_3over2_model<n,modulus>::mul_by_non_residue((c * c1 + b * c2))).inverse();
return Fp6_3over2_model<n,modulus>(t6 * c0, t6 * c1, t6 * c2);
}
template<mp_size_t n, const bigint<n>& modulus>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::Frobenius_map(uint64_t power) const
{
return Fp6_3over2_model<n,modulus>(c0.Frobenius_map(power),
Frobenius_coeffs_c1[power % 6] * c1.Frobenius_map(power),
Frobenius_coeffs_c2[power % 6] * c2.Frobenius_map(power));
}
template<mp_size_t n, const bigint<n>& modulus>
template<mp_size_t m>
Fp6_3over2_model<n,modulus> Fp6_3over2_model<n,modulus>::operator^(const bigint<m> &pow) const
{
return power<Fp6_3over2_model<n, modulus>, m>(*this, pow);
}
template<mp_size_t n, const bigint<n>& modulus>
std::ostream& operator<<(std::ostream &out, const Fp6_3over2_model<n, modulus> &el)
{
out << el.c0 << OUTPUT_SEPARATOR << el.c1 << OUTPUT_SEPARATOR << el.c2;
return out;
}
template<mp_size_t n, const bigint<n>& modulus>
std::istream& operator>>(std::istream &in, Fp6_3over2_model<n, modulus> &el)
{
in >> el.c0 >> el.c1 >> el.c2;
return in;
}
template<mp_size_t n, const bigint<n>& modulus>
std::ostream& operator<<(std::ostream& out, const std::vector<Fp6_3over2_model<n, modulus> > &v)
{
out << v.size() << "\n";
for (const Fp6_3over2_model<n, modulus>& t : v)
{
out << t << OUTPUT_NEWLINE;
}
return out;
}
template<mp_size_t n, const bigint<n>& modulus>
std::istream& operator>>(std::istream& in, std::vector<Fp6_3over2_model<n, modulus> > &v)
{
v.clear();
uint64_t s;
in >> s;
char b;
in.read(&b, 1);
v.reserve(s);
for (size_t i = 0; i < s; ++i)
{
Fp6_3over2_model<n, modulus> el;
in >> el;
v.emplace_back(el);
}
return in;
}
} // libsnark
#endif // FP6_3_OVER_2_TCC_