erigon-pulse/crypto/bls12381/gt.go
2020-06-15 19:38:54 +03:00

123 lines
3.2 KiB
Go

// Copyright 2020 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum 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 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum 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 the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//nolint:stylecheck
package bls12381
import (
"errors"
"math/big"
)
// E is type for target group element
type E = fe12
// GT is type for target multiplicative group GT.
type GT struct {
fp12 *fp12
}
func (e *E) Set(e2 *E) *E {
return e.set(e2)
}
// One sets a new target group element to one
func (e *E) One() *E {
e = new(fe12).one()
return e
}
// IsOne returns true if given element equals to one
func (e *E) IsOne() bool {
return e.isOne()
}
// Equal returns true if given two element is equal, otherwise returns false
func (g *E) Equal(g2 *E) bool {
return g.equal(g2)
}
// NewGT constructs new target group instance.
func NewGT() *GT {
fp12 := newFp12(nil)
return &GT{fp12}
}
// Q returns group order in big.Int.
func (g *GT) Q() *big.Int {
return new(big.Int).Set(q)
}
// FromBytes expects 576 byte input and returns target group element
// FromBytes returns error if given element is not on correct subgroup.
func (g *GT) FromBytes(in []byte) (*E, error) {
e, err := g.fp12.fromBytes(in)
if err != nil {
return nil, err
}
if !g.IsValid(e) {
return e, errors.New("invalid element")
}
return e, nil
}
// ToBytes serializes target group element.
func (g *GT) ToBytes(e *E) []byte {
return g.fp12.toBytes(e)
}
// IsValid checks whether given target group element is in correct subgroup.
func (g *GT) IsValid(e *E) bool {
r := g.New()
g.fp12.exp(r, e, q)
return r.isOne()
}
// New initializes a new target group element which is equal to one
func (g *GT) New() *E {
return new(E).One()
}
// Add adds two field element `a` and `b` and assigns the result to the element in first argument.
func (g *GT) Add(c, a, b *E) {
g.fp12.add(c, a, b)
}
// Sub subtracts two field element `a` and `b`, and assigns the result to the element in first argument.
func (g *GT) Sub(c, a, b *E) {
g.fp12.sub(c, a, b)
}
// Mul multiplies two field element `a` and `b` and assigns the result to the element in first argument.
func (g *GT) Mul(c, a, b *E) {
g.fp12.mul(c, a, b)
}
// Square squares an element `a` and assigns the result to the element in first argument.
func (g *GT) Square(c, a *E) {
g.fp12.cyclotomicSquare(c, a)
}
// Exp exponents an element `a` by a scalar `s` and assigns the result to the element in first argument.
func (g *GT) Exp(c, a *E, s *big.Int) {
g.fp12.cyclotomicExp(c, a, s)
}
// Inverse inverses an element `a` and assigns the result to the element in first argument.
func (g *GT) Inverse(c, a *E) {
g.fp12.inverse(c, a)
}