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// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// For details of the algorithms used, see "Multiplication and Squaring on
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// Pairing-Friendly Fields, Devegili et al.
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// http://eprint.iacr.org/2006/471.pdf.
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// gfP12 implements the field of size p¹² as a quadratic extension of gfP6
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x, y *gfP6 // value is xω + y
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func newGFp12(pool *bnPool) *gfP12 {
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return &gfP12{newGFp6(pool), newGFp6(pool)}
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func (e *gfP12) String() string {
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return "(" + e.x.String() + "," + e.y.String() + ")"
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func (e *gfP12) Put(pool *bnPool) {
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func (e *gfP12) Set(a *gfP12) *gfP12 {
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func (e *gfP12) SetZero() *gfP12 {
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func (e *gfP12) SetOne() *gfP12 {
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func (e *gfP12) Minimal() {
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func (e *gfP12) IsZero() bool {
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return e.x.IsZero() && e.y.IsZero()
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func (e *gfP12) IsOne() bool {
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return e.x.IsZero() && e.y.IsOne()
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func (e *gfP12) Conjugate(a *gfP12) *gfP12 {
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func (e *gfP12) Negative(a *gfP12) *gfP12 {
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// Frobenius computes (xω+y)^p = x^p ω·ξ^((p-1)/6) + y^p
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func (e *gfP12) Frobenius(a *gfP12, pool *bnPool) *gfP12 {
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e.x.Frobenius(a.x, pool)
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e.y.Frobenius(a.y, pool)
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e.x.MulScalar(e.x, xiToPMinus1Over6, pool)
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// FrobeniusP2 computes (xω+y)^p² = x^p² ω·ξ^((p²-1)/6) + y^p²
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func (e *gfP12) FrobeniusP2(a *gfP12, pool *bnPool) *gfP12 {
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e.x.MulGFP(e.x, xiToPSquaredMinus1Over6)
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func (e *gfP12) Add(a, b *gfP12) *gfP12 {
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func (e *gfP12) Sub(a, b *gfP12) *gfP12 {
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func (e *gfP12) Mul(a, b *gfP12, pool *bnPool) *gfP12 {
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tx.Mul(a.x, b.y, pool)
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t.Mul(b.x, a.y, pool)
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ty.Mul(a.y, b.y, pool)
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t.Mul(a.x, b.x, pool)
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func (e *gfP12) MulScalar(a *gfP12, b *gfP6, pool *bnPool) *gfP12 {
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e.x.Mul(e.x, b, pool)
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e.y.Mul(e.y, b, pool)
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func (c *gfP12) Exp(a *gfP12, power *big.Int, pool *bnPool) *gfP12 {
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sum := newGFp12(pool)
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for i := power.BitLen() - 1; i >= 0; i-- {
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if power.Bit(i) != 0 {
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func (e *gfP12) Square(a *gfP12, pool *bnPool) *gfP12 {
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// Complex squaring algorithm
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v0.Mul(a.x, a.y, pool)
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func (e *gfP12) Invert(a *gfP12, pool *bnPool) *gfP12 {
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// See "Implementing cryptographic pairings", M. Scott, section 3.2.
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// ftp://136.206.11.249/pub/crypto/pairings.pdf
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e.MulScalar(e, t2, pool)