From 38ee83e45b4de7edf89bf9f0ef629eb4c6ad0fa8 Mon Sep 17 00:00:00 2001 From: Christopher Speller Date: Thu, 12 May 2016 23:56:07 -0400 Subject: Moving to glide --- vendor/golang.org/x/crypto/bn256/gfp12.go | 200 ++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 vendor/golang.org/x/crypto/bn256/gfp12.go (limited to 'vendor/golang.org/x/crypto/bn256/gfp12.go') diff --git a/vendor/golang.org/x/crypto/bn256/gfp12.go b/vendor/golang.org/x/crypto/bn256/gfp12.go new file mode 100644 index 000000000..f084eddf2 --- /dev/null +++ b/vendor/golang.org/x/crypto/bn256/gfp12.go @@ -0,0 +1,200 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package bn256 + +// For details of the algorithms used, see "Multiplication and Squaring on +// Pairing-Friendly Fields, Devegili et al. +// http://eprint.iacr.org/2006/471.pdf. + +import ( + "math/big" +) + +// gfP12 implements the field of size p¹² as a quadratic extension of gfP6 +// where ω²=τ. +type gfP12 struct { + x, y *gfP6 // value is xω + y +} + +func newGFp12(pool *bnPool) *gfP12 { + return &gfP12{newGFp6(pool), newGFp6(pool)} +} + +func (e *gfP12) String() string { + return "(" + e.x.String() + "," + e.y.String() + ")" +} + +func (e *gfP12) Put(pool *bnPool) { + e.x.Put(pool) + e.y.Put(pool) +} + +func (e *gfP12) Set(a *gfP12) *gfP12 { + e.x.Set(a.x) + e.y.Set(a.y) + return e +} + +func (e *gfP12) SetZero() *gfP12 { + e.x.SetZero() + e.y.SetZero() + return e +} + +func (e *gfP12) SetOne() *gfP12 { + e.x.SetZero() + e.y.SetOne() + return e +} + +func (e *gfP12) Minimal() { + e.x.Minimal() + e.y.Minimal() +} + +func (e *gfP12) IsZero() bool { + e.Minimal() + return e.x.IsZero() && e.y.IsZero() +} + +func (e *gfP12) IsOne() bool { + e.Minimal() + return e.x.IsZero() && e.y.IsOne() +} + +func (e *gfP12) Conjugate(a *gfP12) *gfP12 { + e.x.Negative(a.x) + e.y.Set(a.y) + return a +} + +func (e *gfP12) Negative(a *gfP12) *gfP12 { + e.x.Negative(a.x) + e.y.Negative(a.y) + return e +} + +// Frobenius computes (xω+y)^p = x^p ω·ξ^((p-1)/6) + y^p +func (e *gfP12) Frobenius(a *gfP12, pool *bnPool) *gfP12 { + e.x.Frobenius(a.x, pool) + e.y.Frobenius(a.y, pool) + e.x.MulScalar(e.x, xiToPMinus1Over6, pool) + return e +} + +// FrobeniusP2 computes (xω+y)^p² = x^p² ω·ξ^((p²-1)/6) + y^p² +func (e *gfP12) FrobeniusP2(a *gfP12, pool *bnPool) *gfP12 { + e.x.FrobeniusP2(a.x) + e.x.MulGFP(e.x, xiToPSquaredMinus1Over6) + e.y.FrobeniusP2(a.y) + return e +} + +func (e *gfP12) Add(a, b *gfP12) *gfP12 { + e.x.Add(a.x, b.x) + e.y.Add(a.y, b.y) + return e +} + +func (e *gfP12) Sub(a, b *gfP12) *gfP12 { + e.x.Sub(a.x, b.x) + e.y.Sub(a.y, b.y) + return e +} + +func (e *gfP12) Mul(a, b *gfP12, pool *bnPool) *gfP12 { + tx := newGFp6(pool) + tx.Mul(a.x, b.y, pool) + t := newGFp6(pool) + t.Mul(b.x, a.y, pool) + tx.Add(tx, t) + + ty := newGFp6(pool) + ty.Mul(a.y, b.y, pool) + t.Mul(a.x, b.x, pool) + t.MulTau(t, pool) + e.y.Add(ty, t) + e.x.Set(tx) + + tx.Put(pool) + ty.Put(pool) + t.Put(pool) + return e +} + +func (e *gfP12) MulScalar(a *gfP12, b *gfP6, pool *bnPool) *gfP12 { + e.x.Mul(e.x, b, pool) + e.y.Mul(e.y, b, pool) + return e +} + +func (c *gfP12) Exp(a *gfP12, power *big.Int, pool *bnPool) *gfP12 { + sum := newGFp12(pool) + sum.SetOne() + t := newGFp12(pool) + + for i := power.BitLen() - 1; i >= 0; i-- { + t.Square(sum, pool) + if power.Bit(i) != 0 { + sum.Mul(t, a, pool) + } else { + sum.Set(t) + } + } + + c.Set(sum) + + sum.Put(pool) + t.Put(pool) + + return c +} + +func (e *gfP12) Square(a *gfP12, pool *bnPool) *gfP12 { + // Complex squaring algorithm + v0 := newGFp6(pool) + v0.Mul(a.x, a.y, pool) + + t := newGFp6(pool) + t.MulTau(a.x, pool) + t.Add(a.y, t) + ty := newGFp6(pool) + ty.Add(a.x, a.y) + ty.Mul(ty, t, pool) + ty.Sub(ty, v0) + t.MulTau(v0, pool) + ty.Sub(ty, t) + + e.y.Set(ty) + e.x.Double(v0) + + v0.Put(pool) + t.Put(pool) + ty.Put(pool) + + return e +} + +func (e *gfP12) Invert(a *gfP12, pool *bnPool) *gfP12 { + // See "Implementing cryptographic pairings", M. Scott, section 3.2. + // ftp://136.206.11.249/pub/crypto/pairings.pdf + t1 := newGFp6(pool) + t2 := newGFp6(pool) + + t1.Square(a.x, pool) + t2.Square(a.y, pool) + t1.MulTau(t1, pool) + t1.Sub(t2, t1) + t2.Invert(t1, pool) + + e.x.Negative(a.x) + e.y.Set(a.y) + e.MulScalar(e, t2, pool) + + t1.Put(pool) + t2.Put(pool) + + return e +} -- cgit v1.2.3-1-g7c22