diff options
| author | Emile <git@emile.space> | 2024-10-25 15:55:50 +0200 |
|---|---|---|
| committer | Emile <git@emile.space> | 2024-10-25 15:55:50 +0200 |
| commit | c90f36e3dd179d2de96f4f5fe38d8dc9a9de6dfe (patch) | |
| tree | 89e9afb41c5bf76f48cfb09305a2d3db8d302b06 /vendor/filippo.io/edwards25519 | |
| parent | 98bbb0f559a8883bc47bae80607dbe326a448e61 (diff) | |
Diffstat (limited to 'vendor/filippo.io/edwards25519')
18 files changed, 3883 insertions, 0 deletions
diff --git a/vendor/filippo.io/edwards25519/LICENSE b/vendor/filippo.io/edwards25519/LICENSE new file mode 100644 index 0000000..6a66aea --- /dev/null +++ b/vendor/filippo.io/edwards25519/LICENSE @@ -0,0 +1,27 @@ +Copyright (c) 2009 The Go Authors. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above +copyright notice, this list of conditions and the following disclaimer +in the documentation and/or other materials provided with the +distribution. + * Neither the name of Google Inc. nor the names of its +contributors may be used to endorse or promote products derived from +this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/vendor/filippo.io/edwards25519/README.md b/vendor/filippo.io/edwards25519/README.md new file mode 100644 index 0000000..24e2457 --- /dev/null +++ b/vendor/filippo.io/edwards25519/README.md @@ -0,0 +1,14 @@ +# filippo.io/edwards25519 + +``` +import "filippo.io/edwards25519" +``` + +This library implements the edwards25519 elliptic curve, exposing the necessary APIs to build a wide array of higher-level primitives. +Read the docs at [pkg.go.dev/filippo.io/edwards25519](https://pkg.go.dev/filippo.io/edwards25519). + +The code is originally derived from Adam Langley's internal implementation in the Go standard library, and includes George Tankersley's [performance improvements](https://golang.org/cl/71950). It was then further developed by Henry de Valence for use in ristretto255, and was finally [merged back into the Go standard library](https://golang.org/cl/276272) as of Go 1.17. It now tracks the upstream codebase and extends it with additional functionality. + +Most users don't need this package, and should instead use `crypto/ed25519` for signatures, `golang.org/x/crypto/curve25519` for Diffie-Hellman, or `github.com/gtank/ristretto255` for prime order group logic. However, for anyone currently using a fork of `crypto/internal/edwards25519`/`crypto/ed25519/internal/edwards25519` or `github.com/agl/edwards25519`, this package should be a safer, faster, and more powerful alternative. + +Since this package is meant to curb proliferation of edwards25519 implementations in the Go ecosystem, it welcomes requests for new APIs or reviewable performance improvements. diff --git a/vendor/filippo.io/edwards25519/doc.go b/vendor/filippo.io/edwards25519/doc.go new file mode 100644 index 0000000..ab6aaeb --- /dev/null +++ b/vendor/filippo.io/edwards25519/doc.go @@ -0,0 +1,20 @@ +// Copyright (c) 2021 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 edwards25519 implements group logic for the twisted Edwards curve +// +// -x^2 + y^2 = 1 + -(121665/121666)*x^2*y^2 +// +// This is better known as the Edwards curve equivalent to Curve25519, and is +// the curve used by the Ed25519 signature scheme. +// +// Most users don't need this package, and should instead use crypto/ed25519 for +// signatures, golang.org/x/crypto/curve25519 for Diffie-Hellman, or +// github.com/gtank/ristretto255 for prime order group logic. +// +// However, developers who do need to interact with low-level edwards25519 +// operations can use this package, which is an extended version of +// crypto/internal/edwards25519 from the standard library repackaged as +// an importable module. +package edwards25519 diff --git a/vendor/filippo.io/edwards25519/edwards25519.go b/vendor/filippo.io/edwards25519/edwards25519.go new file mode 100644 index 0000000..a744da2 --- /dev/null +++ b/vendor/filippo.io/edwards25519/edwards25519.go @@ -0,0 +1,427 @@ +// Copyright (c) 2017 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 edwards25519 + +import ( + "errors" + + "filippo.io/edwards25519/field" +) + +// Point types. + +type projP1xP1 struct { + X, Y, Z, T field.Element +} + +type projP2 struct { + X, Y, Z field.Element +} + +// Point represents a point on the edwards25519 curve. +// +// This type works similarly to math/big.Int, and all arguments and receivers +// are allowed to alias. +// +// The zero value is NOT valid, and it may be used only as a receiver. +type Point struct { + // Make the type not comparable (i.e. used with == or as a map key), as + // equivalent points can be represented by different Go values. + _ incomparable + + // The point is internally represented in extended coordinates (X, Y, Z, T) + // where x = X/Z, y = Y/Z, and xy = T/Z per https://eprint.iacr.org/2008/522. + x, y, z, t field.Element +} + +type incomparable [0]func() + +func checkInitialized(points ...*Point) { + for _, p := range points { + if p.x == (field.Element{}) && p.y == (field.Element{}) { + panic("edwards25519: use of uninitialized Point") + } + } +} + +type projCached struct { + YplusX, YminusX, Z, T2d field.Element +} + +type affineCached struct { + YplusX, YminusX, T2d field.Element +} + +// Constructors. + +func (v *projP2) Zero() *projP2 { + v.X.Zero() + v.Y.One() + v.Z.One() + return v +} + +// identity is the point at infinity. +var identity, _ = new(Point).SetBytes([]byte{ + 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}) + +// NewIdentityPoint returns a new Point set to the identity. +func NewIdentityPoint() *Point { + return new(Point).Set(identity) +} + +// generator is the canonical curve basepoint. See TestGenerator for the +// correspondence of this encoding with the values in RFC 8032. +var generator, _ = new(Point).SetBytes([]byte{ + 0x58, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, + 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, + 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, + 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66}) + +// NewGeneratorPoint returns a new Point set to the canonical generator. +func NewGeneratorPoint() *Point { + return new(Point).Set(generator) +} + +func (v *projCached) Zero() *projCached { + v.YplusX.One() + v.YminusX.One() + v.Z.One() + v.T2d.Zero() + return v +} + +func (v *affineCached) Zero() *affineCached { + v.YplusX.One() + v.YminusX.One() + v.T2d.Zero() + return v +} + +// Assignments. + +// Set sets v = u, and returns v. +func (v *Point) Set(u *Point) *Point { + *v = *u + return v +} + +// Encoding. + +// Bytes returns the canonical 32-byte encoding of v, according to RFC 8032, +// Section 5.1.2. +func (v *Point) Bytes() []byte { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. + var buf [32]byte + return v.bytes(&buf) +} + +func (v *Point) bytes(buf *[32]byte) []byte { + checkInitialized(v) + + var zInv, x, y field.Element + zInv.Invert(&v.z) // zInv = 1 / Z + x.Multiply(&v.x, &zInv) // x = X / Z + y.Multiply(&v.y, &zInv) // y = Y / Z + + out := copyFieldElement(buf, &y) + out[31] |= byte(x.IsNegative() << 7) + return out +} + +var feOne = new(field.Element).One() + +// SetBytes sets v = x, where x is a 32-byte encoding of v. If x does not +// represent a valid point on the curve, SetBytes returns nil and an error and +// the receiver is unchanged. Otherwise, SetBytes returns v. +// +// Note that SetBytes accepts all non-canonical encodings of valid points. +// That is, it follows decoding rules that match most implementations in +// the ecosystem rather than RFC 8032. +func (v *Point) SetBytes(x []byte) (*Point, error) { + // Specifically, the non-canonical encodings that are accepted are + // 1) the ones where the field element is not reduced (see the + // (*field.Element).SetBytes docs) and + // 2) the ones where the x-coordinate is zero and the sign bit is set. + // + // Read more at https://hdevalence.ca/blog/2020-10-04-its-25519am, + // specifically the "Canonical A, R" section. + + y, err := new(field.Element).SetBytes(x) + if err != nil { + return nil, errors.New("edwards25519: invalid point encoding length") + } + + // -x² + y² = 1 + dx²y² + // x² + dx²y² = x²(dy² + 1) = y² - 1 + // x² = (y² - 1) / (dy² + 1) + + // u = y² - 1 + y2 := new(field.Element).Square(y) + u := new(field.Element).Subtract(y2, feOne) + + // v = dy² + 1 + vv := new(field.Element).Multiply(y2, d) + vv = vv.Add(vv, feOne) + + // x = +√(u/v) + xx, wasSquare := new(field.Element).SqrtRatio(u, vv) + if wasSquare == 0 { + return nil, errors.New("edwards25519: invalid point encoding") + } + + // Select the negative square root if the sign bit is set. + xxNeg := new(field.Element).Negate(xx) + xx = xx.Select(xxNeg, xx, int(x[31]>>7)) + + v.x.Set(xx) + v.y.Set(y) + v.z.One() + v.t.Multiply(xx, y) // xy = T / Z + + return v, nil +} + +func copyFieldElement(buf *[32]byte, v *field.Element) []byte { + copy(buf[:], v.Bytes()) + return buf[:] +} + +// Conversions. + +func (v *projP2) FromP1xP1(p *projP1xP1) *projP2 { + v.X.Multiply(&p.X, &p.T) + v.Y.Multiply(&p.Y, &p.Z) + v.Z.Multiply(&p.Z, &p.T) + return v +} + +func (v *projP2) FromP3(p *Point) *projP2 { + v.X.Set(&p.x) + v.Y.Set(&p.y) + v.Z.Set(&p.z) + return v +} + +func (v *Point) fromP1xP1(p *projP1xP1) *Point { + v.x.Multiply(&p.X, &p.T) + v.y.Multiply(&p.Y, &p.Z) + v.z.Multiply(&p.Z, &p.T) + v.t.Multiply(&p.X, &p.Y) + return v +} + +func (v *Point) fromP2(p *projP2) *Point { + v.x.Multiply(&p.X, &p.Z) + v.y.Multiply(&p.Y, &p.Z) + v.z.Square(&p.Z) + v.t.Multiply(&p.X, &p.Y) + return v +} + +// d is a constant in the curve equation. +var d, _ = new(field.Element).SetBytes([]byte{ + 0xa3, 0x78, 0x59, 0x13, 0xca, 0x4d, 0xeb, 0x75, + 0xab, 0xd8, 0x41, 0x41, 0x4d, 0x0a, 0x70, 0x00, + 0x98, 0xe8, 0x79, 0x77, 0x79, 0x40, 0xc7, 0x8c, + 0x73, 0xfe, 0x6f, 0x2b, 0xee, 0x6c, 0x03, 0x52}) +var d2 = new(field.Element).Add(d, d) + +func (v *projCached) FromP3(p *Point) *projCached { + v.YplusX.Add(&p.y, &p.x) + v.YminusX.Subtract(&p.y, &p.x) + v.Z.Set(&p.z) + v.T2d.Multiply(&p.t, d2) + return v +} + +func (v *affineCached) FromP3(p *Point) *affineCached { + v.YplusX.Add(&p.y, &p.x) + v.YminusX.Subtract(&p.y, &p.x) + v.T2d.Multiply(&p.t, d2) + + var invZ field.Element + invZ.Invert(&p.z) + v.YplusX.Multiply(&v.YplusX, &invZ) + v.YminusX.Multiply(&v.YminusX, &invZ) + v.T2d.Multiply(&v.T2d, &invZ) + return v +} + +// (Re)addition and subtraction. + +// Add sets v = p + q, and returns v. +func (v *Point) Add(p, q *Point) *Point { + checkInitialized(p, q) + qCached := new(projCached).FromP3(q) + result := new(projP1xP1).Add(p, qCached) + return v.fromP1xP1(result) +} + +// Subtract sets v = p - q, and returns v. +func (v *Point) Subtract(p, q *Point) *Point { + checkInitialized(p, q) + qCached := new(projCached).FromP3(q) + result := new(projP1xP1).Sub(p, qCached) + return v.fromP1xP1(result) +} + +func (v *projP1xP1) Add(p *Point, q *projCached) *projP1xP1 { + var YplusX, YminusX, PP, MM, TT2d, ZZ2 field.Element + + YplusX.Add(&p.y, &p.x) + YminusX.Subtract(&p.y, &p.x) + + PP.Multiply(&YplusX, &q.YplusX) + MM.Multiply(&YminusX, &q.YminusX) + TT2d.Multiply(&p.t, &q.T2d) + ZZ2.Multiply(&p.z, &q.Z) + + ZZ2.Add(&ZZ2, &ZZ2) + + v.X.Subtract(&PP, &MM) + v.Y.Add(&PP, &MM) + v.Z.Add(&ZZ2, &TT2d) + v.T.Subtract(&ZZ2, &TT2d) + return v +} + +func (v *projP1xP1) Sub(p *Point, q *projCached) *projP1xP1 { + var YplusX, YminusX, PP, MM, TT2d, ZZ2 field.Element + + YplusX.Add(&p.y, &p.x) + YminusX.Subtract(&p.y, &p.x) + + PP.Multiply(&YplusX, &q.YminusX) // flipped sign + MM.Multiply(&YminusX, &q.YplusX) // flipped sign + TT2d.Multiply(&p.t, &q.T2d) + ZZ2.Multiply(&p.z, &q.Z) + + ZZ2.Add(&ZZ2, &ZZ2) + + v.X.Subtract(&PP, &MM) + v.Y.Add(&PP, &MM) + v.Z.Subtract(&ZZ2, &TT2d) // flipped sign + v.T.Add(&ZZ2, &TT2d) // flipped sign + return v +} + +func (v *projP1xP1) AddAffine(p *Point, q *affineCached) *projP1xP1 { + var YplusX, YminusX, PP, MM, TT2d, Z2 field.Element + + YplusX.Add(&p.y, &p.x) + YminusX.Subtract(&p.y, &p.x) + + PP.Multiply(&YplusX, &q.YplusX) + MM.Multiply(&YminusX, &q.YminusX) + TT2d.Multiply(&p.t, &q.T2d) + + Z2.Add(&p.z, &p.z) + + v.X.Subtract(&PP, &MM) + v.Y.Add(&PP, &MM) + v.Z.Add(&Z2, &TT2d) + v.T.Subtract(&Z2, &TT2d) + return v +} + +func (v *projP1xP1) SubAffine(p *Point, q *affineCached) *projP1xP1 { + var YplusX, YminusX, PP, MM, TT2d, Z2 field.Element + + YplusX.Add(&p.y, &p.x) + YminusX.Subtract(&p.y, &p.x) + + PP.Multiply(&YplusX, &q.YminusX) // flipped sign + MM.Multiply(&YminusX, &q.YplusX) // flipped sign + TT2d.Multiply(&p.t, &q.T2d) + + Z2.Add(&p.z, &p.z) + + v.X.Subtract(&PP, &MM) + v.Y.Add(&PP, &MM) + v.Z.Subtract(&Z2, &TT2d) // flipped sign + v.T.Add(&Z2, &TT2d) // flipped sign + return v +} + +// Doubling. + +func (v *projP1xP1) Double(p *projP2) *projP1xP1 { + var XX, YY, ZZ2, XplusYsq field.Element + + XX.Square(&p.X) + YY.Square(&p.Y) + ZZ2.Square(&p.Z) + ZZ2.Add(&ZZ2, &ZZ2) + XplusYsq.Add(&p.X, &p.Y) + XplusYsq.Square(&XplusYsq) + + v.Y.Add(&YY, &XX) + v.Z.Subtract(&YY, &XX) + + v.X.Subtract(&XplusYsq, &v.Y) + v.T.Subtract(&ZZ2, &v.Z) + return v +} + +// Negation. + +// Negate sets v = -p, and returns v. +func (v *Point) Negate(p *Point) *Point { + checkInitialized(p) + v.x.Negate(&p.x) + v.y.Set(&p.y) + v.z.Set(&p.z) + v.t.Negate(&p.t) + return v +} + +// Equal returns 1 if v is equivalent to u, and 0 otherwise. +func (v *Point) Equal(u *Point) int { + checkInitialized(v, u) + + var t1, t2, t3, t4 field.Element + t1.Multiply(&v.x, &u.z) + t2.Multiply(&u.x, &v.z) + t3.Multiply(&v.y, &u.z) + t4.Multiply(&u.y, &v.z) + + return t1.Equal(&t2) & t3.Equal(&t4) +} + +// Constant-time operations + +// Select sets v to a if cond == 1 and to b if cond == 0. +func (v *projCached) Select(a, b *projCached, cond int) *projCached { + v.YplusX.Select(&a.YplusX, &b.YplusX, cond) + v.YminusX.Select(&a.YminusX, &b.YminusX, cond) + v.Z.Select(&a.Z, &b.Z, cond) + v.T2d.Select(&a.T2d, &b.T2d, cond) + return v +} + +// Select sets v to a if cond == 1 and to b if cond == 0. +func (v *affineCached) Select(a, b *affineCached, cond int) *affineCached { + v.YplusX.Select(&a.YplusX, &b.YplusX, cond) + v.YminusX.Select(&a.YminusX, &b.YminusX, cond) + v.T2d.Select(&a.T2d, &b.T2d, cond) + return v +} + +// CondNeg negates v if cond == 1 and leaves it unchanged if cond == 0. +func (v *projCached) CondNeg(cond int) *projCached { + v.YplusX.Swap(&v.YminusX, cond) + v.T2d.Select(new(field.Element).Negate(&v.T2d), &v.T2d, cond) + return v +} + +// CondNeg negates v if cond == 1 and leaves it unchanged if cond == 0. +func (v *affineCached) CondNeg(cond int) *affineCached { + v.YplusX.Swap(&v.YminusX, cond) + v.T2d.Select(new(field.Element).Negate(&v.T2d), &v.T2d, cond) + return v +} diff --git a/vendor/filippo.io/edwards25519/extra.go b/vendor/filippo.io/edwards25519/extra.go new file mode 100644 index 0000000..d152d68 --- /dev/null +++ b/vendor/filippo.io/edwards25519/extra.go @@ -0,0 +1,349 @@ +// Copyright (c) 2021 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 edwards25519 + +// This file contains additional functionality that is not included in the +// upstream crypto/internal/edwards25519 package. + +import ( + "errors" + + "filippo.io/edwards25519/field" +) + +// ExtendedCoordinates returns v in extended coordinates (X:Y:Z:T) where +// x = X/Z, y = Y/Z, and xy = T/Z as in https://eprint.iacr.org/2008/522. +func (v *Point) ExtendedCoordinates() (X, Y, Z, T *field.Element) { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. Don't change the style without making + // sure it doesn't increase the inliner cost. + var e [4]field.Element + X, Y, Z, T = v.extendedCoordinates(&e) + return +} + +func (v *Point) extendedCoordinates(e *[4]field.Element) (X, Y, Z, T *field.Element) { + checkInitialized(v) + X = e[0].Set(&v.x) + Y = e[1].Set(&v.y) + Z = e[2].Set(&v.z) + T = e[3].Set(&v.t) + return +} + +// SetExtendedCoordinates sets v = (X:Y:Z:T) in extended coordinates where +// x = X/Z, y = Y/Z, and xy = T/Z as in https://eprint.iacr.org/2008/522. +// +// If the coordinates are invalid or don't represent a valid point on the curve, +// SetExtendedCoordinates returns nil and an error and the receiver is +// unchanged. Otherwise, SetExtendedCoordinates returns v. +func (v *Point) SetExtendedCoordinates(X, Y, Z, T *field.Element) (*Point, error) { + if !isOnCurve(X, Y, Z, T) { + return nil, errors.New("edwards25519: invalid point coordinates") + } + v.x.Set(X) + v.y.Set(Y) + v.z.Set(Z) + v.t.Set(T) + return v, nil +} + +func isOnCurve(X, Y, Z, T *field.Element) bool { + var lhs, rhs field.Element + XX := new(field.Element).Square(X) + YY := new(field.Element).Square(Y) + ZZ := new(field.Element).Square(Z) + TT := new(field.Element).Square(T) + // -x² + y² = 1 + dx²y² + // -(X/Z)² + (Y/Z)² = 1 + d(T/Z)² + // -X² + Y² = Z² + dT² + lhs.Subtract(YY, XX) + rhs.Multiply(d, TT).Add(&rhs, ZZ) + if lhs.Equal(&rhs) != 1 { + return false + } + // xy = T/Z + // XY/Z² = T/Z + // XY = TZ + lhs.Multiply(X, Y) + rhs.Multiply(T, Z) + return lhs.Equal(&rhs) == 1 +} + +// BytesMontgomery converts v to a point on the birationally-equivalent +// Curve25519 Montgomery curve, and returns its canonical 32 bytes encoding +// according to RFC 7748. +// +// Note that BytesMontgomery only encodes the u-coordinate, so v and -v encode +// to the same value. If v is the identity point, BytesMontgomery returns 32 +// zero bytes, analogously to the X25519 function. +// +// The lack of an inverse operation (such as SetMontgomeryBytes) is deliberate: +// while every valid edwards25519 point has a unique u-coordinate Montgomery +// encoding, X25519 accepts inputs on the quadratic twist, which don't correspond +// to any edwards25519 point, and every other X25519 input corresponds to two +// edwards25519 points. +func (v *Point) BytesMontgomery() []byte { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. + var buf [32]byte + return v.bytesMontgomery(&buf) +} + +func (v *Point) bytesMontgomery(buf *[32]byte) []byte { + checkInitialized(v) + + // RFC 7748, Section 4.1 provides the bilinear map to calculate the + // Montgomery u-coordinate + // + // u = (1 + y) / (1 - y) + // + // where y = Y / Z. + + var y, recip, u field.Element + + y.Multiply(&v.y, y.Invert(&v.z)) // y = Y / Z + recip.Invert(recip.Subtract(feOne, &y)) // r = 1/(1 - y) + u.Multiply(u.Add(feOne, &y), &recip) // u = (1 + y)*r + + return copyFieldElement(buf, &u) +} + +// MultByCofactor sets v = 8 * p, and returns v. +func (v *Point) MultByCofactor(p *Point) *Point { + checkInitialized(p) + result := projP1xP1{} + pp := (&projP2{}).FromP3(p) + result.Double(pp) + pp.FromP1xP1(&result) + result.Double(pp) + pp.FromP1xP1(&result) + result.Double(pp) + return v.fromP1xP1(&result) +} + +// Given k > 0, set s = s**(2*i). +func (s *Scalar) pow2k(k int) { + for i := 0; i < k; i++ { + s.Multiply(s, s) + } +} + +// Invert sets s to the inverse of a nonzero scalar v, and returns s. +// +// If t is zero, Invert returns zero. +func (s *Scalar) Invert(t *Scalar) *Scalar { + // Uses a hardcoded sliding window of width 4. + var table [8]Scalar + var tt Scalar + tt.Multiply(t, t) + table[0] = *t + for i := 0; i < 7; i++ { + table[i+1].Multiply(&table[i], &tt) + } + // Now table = [t**1, t**3, t**5, t**7, t**9, t**11, t**13, t**15] + // so t**k = t[k/2] for odd k + + // To compute the sliding window digits, use the following Sage script: + + // sage: import itertools + // sage: def sliding_window(w,k): + // ....: digits = [] + // ....: while k > 0: + // ....: if k % 2 == 1: + // ....: kmod = k % (2**w) + // ....: digits.append(kmod) + // ....: k = k - kmod + // ....: else: + // ....: digits.append(0) + // ....: k = k // 2 + // ....: return digits + + // Now we can compute s roughly as follows: + + // sage: s = 1 + // sage: for coeff in reversed(sliding_window(4,l-2)): + // ....: s = s*s + // ....: if coeff > 0 : + // ....: s = s*t**coeff + + // This works on one bit at a time, with many runs of zeros. + // The digits can be collapsed into [(count, coeff)] as follows: + + // sage: [(len(list(group)),d) for d,group in itertools.groupby(sliding_window(4,l-2))] + + // Entries of the form (k, 0) turn into pow2k(k) + // Entries of the form (1, coeff) turn into a squaring and then a table lookup. + // We can fold the squaring into the previous pow2k(k) as pow2k(k+1). + + *s = table[1/2] + s.pow2k(127 + 1) + s.Multiply(s, &table[1/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[9/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[11/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[13/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[15/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[7/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[15/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[5/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[1/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[15/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[15/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[7/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[3/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[11/2]) + s.pow2k(5 + 1) + s.Multiply(s, &table[11/2]) + s.pow2k(9 + 1) + s.Multiply(s, &table[9/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[3/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[3/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[3/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[9/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[7/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[3/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[13/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[7/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[9/2]) + s.pow2k(3 + 1) + s.Multiply(s, &table[15/2]) + s.pow2k(4 + 1) + s.Multiply(s, &table[11/2]) + + return s +} + +// MultiScalarMult sets v = sum(scalars[i] * points[i]), and returns v. +// +// Execution time depends only on the lengths of the two slices, which must match. +func (v *Point) MultiScalarMult(scalars []*Scalar, points []*Point) *Point { + if len(scalars) != len(points) { + panic("edwards25519: called MultiScalarMult with different size inputs") + } + checkInitialized(points...) + + // Proceed as in the single-base case, but share doublings + // between each point in the multiscalar equation. + + // Build lookup tables for each point + tables := make([]projLookupTable, len(points)) + for i := range tables { + tables[i].FromP3(points[i]) + } + // Compute signed radix-16 digits for each scalar + digits := make([][64]int8, len(scalars)) + for i := range digits { + digits[i] = scalars[i].signedRadix16() + } + + // Unwrap first loop iteration to save computing 16*identity + multiple := &projCached{} + tmp1 := &projP1xP1{} + tmp2 := &projP2{} + // Lookup-and-add the appropriate multiple of each input point + for j := range tables { + tables[j].SelectInto(multiple, digits[j][63]) + tmp1.Add(v, multiple) // tmp1 = v + x_(j,63)*Q in P1xP1 coords + v.fromP1xP1(tmp1) // update v + } + tmp2.FromP3(v) // set up tmp2 = v in P2 coords for next iteration + for i := 62; i >= 0; i-- { + tmp1.Double(tmp2) // tmp1 = 2*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 2*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 4*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 4*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 8*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 8*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 16*(prev) in P1xP1 coords + v.fromP1xP1(tmp1) // v = 16*(prev) in P3 coords + // Lookup-and-add the appropriate multiple of each input point + for j := range tables { + tables[j].SelectInto(multiple, digits[j][i]) + tmp1.Add(v, multiple) // tmp1 = v + x_(j,i)*Q in P1xP1 coords + v.fromP1xP1(tmp1) // update v + } + tmp2.FromP3(v) // set up tmp2 = v in P2 coords for next iteration + } + return v +} + +// VarTimeMultiScalarMult sets v = sum(scalars[i] * points[i]), and returns v. +// +// Execution time depends on the inputs. +func (v *Point) VarTimeMultiScalarMult(scalars []*Scalar, points []*Point) *Point { + if len(scalars) != len(points) { + panic("edwards25519: called VarTimeMultiScalarMult with different size inputs") + } + checkInitialized(points...) + + // Generalize double-base NAF computation to arbitrary sizes. + // Here all the points are dynamic, so we only use the smaller + // tables. + + // Build lookup tables for each point + tables := make([]nafLookupTable5, len(points)) + for i := range tables { + tables[i].FromP3(points[i]) + } + // Compute a NAF for each scalar + nafs := make([][256]int8, len(scalars)) + for i := range nafs { + nafs[i] = scalars[i].nonAdjacentForm(5) + } + + multiple := &projCached{} + tmp1 := &projP1xP1{} + tmp2 := &projP2{} + tmp2.Zero() + + // Move from high to low bits, doubling the accumulator + // at each iteration and checking whether there is a nonzero + // coefficient to look up a multiple of. + // + // Skip trying to find the first nonzero coefficent, because + // searching might be more work than a few extra doublings. + for i := 255; i >= 0; i-- { + tmp1.Double(tmp2) + + for j := range nafs { + if nafs[j][i] > 0 { + v.fromP1xP1(tmp1) + tables[j].SelectInto(multiple, nafs[j][i]) + tmp1.Add(v, multiple) + } else if nafs[j][i] < 0 { + v.fromP1xP1(tmp1) + tables[j].SelectInto(multiple, -nafs[j][i]) + tmp1.Sub(v, multiple) + } + } + + tmp2.FromP1xP1(tmp1) + } + + v.fromP2(tmp2) + return v +} diff --git a/vendor/filippo.io/edwards25519/field/fe.go b/vendor/filippo.io/edwards25519/field/fe.go new file mode 100644 index 0000000..5518ef2 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe.go @@ -0,0 +1,420 @@ +// Copyright (c) 2017 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 field implements fast arithmetic modulo 2^255-19. +package field + +import ( + "crypto/subtle" + "encoding/binary" + "errors" + "math/bits" +) + +// Element represents an element of the field GF(2^255-19). Note that this +// is not a cryptographically secure group, and should only be used to interact +// with edwards25519.Point coordinates. +// +// This type works similarly to math/big.Int, and all arguments and receivers +// are allowed to alias. +// +// The zero value is a valid zero element. +type Element struct { + // An element t represents the integer + // t.l0 + t.l1*2^51 + t.l2*2^102 + t.l3*2^153 + t.l4*2^204 + // + // Between operations, all limbs are expected to be lower than 2^52. + l0 uint64 + l1 uint64 + l2 uint64 + l3 uint64 + l4 uint64 +} + +const maskLow51Bits uint64 = (1 << 51) - 1 + +var feZero = &Element{0, 0, 0, 0, 0} + +// Zero sets v = 0, and returns v. +func (v *Element) Zero() *Element { + *v = *feZero + return v +} + +var feOne = &Element{1, 0, 0, 0, 0} + +// One sets v = 1, and returns v. +func (v *Element) One() *Element { + *v = *feOne + return v +} + +// reduce reduces v modulo 2^255 - 19 and returns it. +func (v *Element) reduce() *Element { + v.carryPropagate() + + // After the light reduction we now have a field element representation + // v < 2^255 + 2^13 * 19, but need v < 2^255 - 19. + + // If v >= 2^255 - 19, then v + 19 >= 2^255, which would overflow 2^255 - 1, + // generating a carry. That is, c will be 0 if v < 2^255 - 19, and 1 otherwise. + c := (v.l0 + 19) >> 51 + c = (v.l1 + c) >> 51 + c = (v.l2 + c) >> 51 + c = (v.l3 + c) >> 51 + c = (v.l4 + c) >> 51 + + // If v < 2^255 - 19 and c = 0, this will be a no-op. Otherwise, it's + // effectively applying the reduction identity to the carry. + v.l0 += 19 * c + + v.l1 += v.l0 >> 51 + v.l0 = v.l0 & maskLow51Bits + v.l2 += v.l1 >> 51 + v.l1 = v.l1 & maskLow51Bits + v.l3 += v.l2 >> 51 + v.l2 = v.l2 & maskLow51Bits + v.l4 += v.l3 >> 51 + v.l3 = v.l3 & maskLow51Bits + // no additional carry + v.l4 = v.l4 & maskLow51Bits + + return v +} + +// Add sets v = a + b, and returns v. +func (v *Element) Add(a, b *Element) *Element { + v.l0 = a.l0 + b.l0 + v.l1 = a.l1 + b.l1 + v.l2 = a.l2 + b.l2 + v.l3 = a.l3 + b.l3 + v.l4 = a.l4 + b.l4 + // Using the generic implementation here is actually faster than the + // assembly. Probably because the body of this function is so simple that + // the compiler can figure out better optimizations by inlining the carry + // propagation. + return v.carryPropagateGeneric() +} + +// Subtract sets v = a - b, and returns v. +func (v *Element) Subtract(a, b *Element) *Element { + // We first add 2 * p, to guarantee the subtraction won't underflow, and + // then subtract b (which can be up to 2^255 + 2^13 * 19). + v.l0 = (a.l0 + 0xFFFFFFFFFFFDA) - b.l0 + v.l1 = (a.l1 + 0xFFFFFFFFFFFFE) - b.l1 + v.l2 = (a.l2 + 0xFFFFFFFFFFFFE) - b.l2 + v.l3 = (a.l3 + 0xFFFFFFFFFFFFE) - b.l3 + v.l4 = (a.l4 + 0xFFFFFFFFFFFFE) - b.l4 + return v.carryPropagate() +} + +// Negate sets v = -a, and returns v. +func (v *Element) Negate(a *Element) *Element { + return v.Subtract(feZero, a) +} + +// Invert sets v = 1/z mod p, and returns v. +// +// If z == 0, Invert returns v = 0. +func (v *Element) Invert(z *Element) *Element { + // Inversion is implemented as exponentiation with exponent p − 2. It uses the + // same sequence of 255 squarings and 11 multiplications as [Curve25519]. + var z2, z9, z11, z2_5_0, z2_10_0, z2_20_0, z2_50_0, z2_100_0, t Element + + z2.Square(z) // 2 + t.Square(&z2) // 4 + t.Square(&t) // 8 + z9.Multiply(&t, z) // 9 + z11.Multiply(&z9, &z2) // 11 + t.Square(&z11) // 22 + z2_5_0.Multiply(&t, &z9) // 31 = 2^5 - 2^0 + + t.Square(&z2_5_0) // 2^6 - 2^1 + for i := 0; i < 4; i++ { + t.Square(&t) // 2^10 - 2^5 + } + z2_10_0.Multiply(&t, &z2_5_0) // 2^10 - 2^0 + + t.Square(&z2_10_0) // 2^11 - 2^1 + for i := 0; i < 9; i++ { + t.Square(&t) // 2^20 - 2^10 + } + z2_20_0.Multiply(&t, &z2_10_0) // 2^20 - 2^0 + + t.Square(&z2_20_0) // 2^21 - 2^1 + for i := 0; i < 19; i++ { + t.Square(&t) // 2^40 - 2^20 + } + t.Multiply(&t, &z2_20_0) // 2^40 - 2^0 + + t.Square(&t) // 2^41 - 2^1 + for i := 0; i < 9; i++ { + t.Square(&t) // 2^50 - 2^10 + } + z2_50_0.Multiply(&t, &z2_10_0) // 2^50 - 2^0 + + t.Square(&z2_50_0) // 2^51 - 2^1 + for i := 0; i < 49; i++ { + t.Square(&t) // 2^100 - 2^50 + } + z2_100_0.Multiply(&t, &z2_50_0) // 2^100 - 2^0 + + t.Square(&z2_100_0) // 2^101 - 2^1 + for i := 0; i < 99; i++ { + t.Square(&t) // 2^200 - 2^100 + } + t.Multiply(&t, &z2_100_0) // 2^200 - 2^0 + + t.Square(&t) // 2^201 - 2^1 + for i := 0; i < 49; i++ { + t.Square(&t) // 2^250 - 2^50 + } + t.Multiply(&t, &z2_50_0) // 2^250 - 2^0 + + t.Square(&t) // 2^251 - 2^1 + t.Square(&t) // 2^252 - 2^2 + t.Square(&t) // 2^253 - 2^3 + t.Square(&t) // 2^254 - 2^4 + t.Square(&t) // 2^255 - 2^5 + + return v.Multiply(&t, &z11) // 2^255 - 21 +} + +// Set sets v = a, and returns v. +func (v *Element) Set(a *Element) *Element { + *v = *a + return v +} + +// SetBytes sets v to x, where x is a 32-byte little-endian encoding. If x is +// not of the right length, SetBytes returns nil and an error, and the +// receiver is unchanged. +// +// Consistent with RFC 7748, the most significant bit (the high bit of the +// last byte) is ignored, and non-canonical values (2^255-19 through 2^255-1) +// are accepted. Note that this is laxer than specified by RFC 8032, but +// consistent with most Ed25519 implementations. +func (v *Element) SetBytes(x []byte) (*Element, error) { + if len(x) != 32 { + return nil, errors.New("edwards25519: invalid field element input size") + } + + // Bits 0:51 (bytes 0:8, bits 0:64, shift 0, mask 51). + v.l0 = binary.LittleEndian.Uint64(x[0:8]) + v.l0 &= maskLow51Bits + // Bits 51:102 (bytes 6:14, bits 48:112, shift 3, mask 51). + v.l1 = binary.LittleEndian.Uint64(x[6:14]) >> 3 + v.l1 &= maskLow51Bits + // Bits 102:153 (bytes 12:20, bits 96:160, shift 6, mask 51). + v.l2 = binary.LittleEndian.Uint64(x[12:20]) >> 6 + v.l2 &= maskLow51Bits + // Bits 153:204 (bytes 19:27, bits 152:216, shift 1, mask 51). + v.l3 = binary.LittleEndian.Uint64(x[19:27]) >> 1 + v.l3 &= maskLow51Bits + // Bits 204:255 (bytes 24:32, bits 192:256, shift 12, mask 51). + // Note: not bytes 25:33, shift 4, to avoid overread. + v.l4 = binary.LittleEndian.Uint64(x[24:32]) >> 12 + v.l4 &= maskLow51Bits + + return v, nil +} + +// Bytes returns the canonical 32-byte little-endian encoding of v. +func (v *Element) Bytes() []byte { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. + var out [32]byte + return v.bytes(&out) +} + +func (v *Element) bytes(out *[32]byte) []byte { + t := *v + t.reduce() + + var buf [8]byte + for i, l := range [5]uint64{t.l0, t.l1, t.l2, t.l3, t.l4} { + bitsOffset := i * 51 + binary.LittleEndian.PutUint64(buf[:], l<<uint(bitsOffset%8)) + for i, bb := range buf { + off := bitsOffset/8 + i + if off >= len(out) { + break + } + out[off] |= bb + } + } + + return out[:] +} + +// Equal returns 1 if v and u are equal, and 0 otherwise. +func (v *Element) Equal(u *Element) int { + sa, sv := u.Bytes(), v.Bytes() + return subtle.ConstantTimeCompare(sa, sv) +} + +// mask64Bits returns 0xffffffff if cond is 1, and 0 otherwise. +func mask64Bits(cond int) uint64 { return ^(uint64(cond) - 1) } + +// Select sets v to a if cond == 1, and to b if cond == 0. +func (v *Element) Select(a, b *Element, cond int) *Element { + m := mask64Bits(cond) + v.l0 = (m & a.l0) | (^m & b.l0) + v.l1 = (m & a.l1) | (^m & b.l1) + v.l2 = (m & a.l2) | (^m & b.l2) + v.l3 = (m & a.l3) | (^m & b.l3) + v.l4 = (m & a.l4) | (^m & b.l4) + return v +} + +// Swap swaps v and u if cond == 1 or leaves them unchanged if cond == 0, and returns v. +func (v *Element) Swap(u *Element, cond int) { + m := mask64Bits(cond) + t := m & (v.l0 ^ u.l0) + v.l0 ^= t + u.l0 ^= t + t = m & (v.l1 ^ u.l1) + v.l1 ^= t + u.l1 ^= t + t = m & (v.l2 ^ u.l2) + v.l2 ^= t + u.l2 ^= t + t = m & (v.l3 ^ u.l3) + v.l3 ^= t + u.l3 ^= t + t = m & (v.l4 ^ u.l4) + v.l4 ^= t + u.l4 ^= t +} + +// IsNegative returns 1 if v is negative, and 0 otherwise. +func (v *Element) IsNegative() int { + return int(v.Bytes()[0] & 1) +} + +// Absolute sets v to |u|, and returns v. +func (v *Element) Absolute(u *Element) *Element { + return v.Select(new(Element).Negate(u), u, u.IsNegative()) +} + +// Multiply sets v = x * y, and returns v. +func (v *Element) Multiply(x, y *Element) *Element { + feMul(v, x, y) + return v +} + +// Square sets v = x * x, and returns v. +func (v *Element) Square(x *Element) *Element { + feSquare(v, x) + return v +} + +// Mult32 sets v = x * y, and returns v. +func (v *Element) Mult32(x *Element, y uint32) *Element { + x0lo, x0hi := mul51(x.l0, y) + x1lo, x1hi := mul51(x.l1, y) + x2lo, x2hi := mul51(x.l2, y) + x3lo, x3hi := mul51(x.l3, y) + x4lo, x4hi := mul51(x.l4, y) + v.l0 = x0lo + 19*x4hi // carried over per the reduction identity + v.l1 = x1lo + x0hi + v.l2 = x2lo + x1hi + v.l3 = x3lo + x2hi + v.l4 = x4lo + x3hi + // The hi portions are going to be only 32 bits, plus any previous excess, + // so we can skip the carry propagation. + return v +} + +// mul51 returns lo + hi * 2⁵¹ = a * b. +func mul51(a uint64, b uint32) (lo uint64, hi uint64) { + mh, ml := bits.Mul64(a, uint64(b)) + lo = ml & maskLow51Bits + hi = (mh << 13) | (ml >> 51) + return +} + +// Pow22523 set v = x^((p-5)/8), and returns v. (p-5)/8 is 2^252-3. +func (v *Element) Pow22523(x *Element) *Element { + var t0, t1, t2 Element + + t0.Square(x) // x^2 + t1.Square(&t0) // x^4 + t1.Square(&t1) // x^8 + t1.Multiply(x, &t1) // x^9 + t0.Multiply(&t0, &t1) // x^11 + t0.Square(&t0) // x^22 + t0.Multiply(&t1, &t0) // x^31 + t1.Square(&t0) // x^62 + for i := 1; i < 5; i++ { // x^992 + t1.Square(&t1) + } + t0.Multiply(&t1, &t0) // x^1023 -> 1023 = 2^10 - 1 + t1.Square(&t0) // 2^11 - 2 + for i := 1; i < 10; i++ { // 2^20 - 2^10 + t1.Square(&t1) + } + t1.Multiply(&t1, &t0) // 2^20 - 1 + t2.Square(&t1) // 2^21 - 2 + for i := 1; i < 20; i++ { // 2^40 - 2^20 + t2.Square(&t2) + } + t1.Multiply(&t2, &t1) // 2^40 - 1 + t1.Square(&t1) // 2^41 - 2 + for i := 1; i < 10; i++ { // 2^50 - 2^10 + t1.Square(&t1) + } + t0.Multiply(&t1, &t0) // 2^50 - 1 + t1.Square(&t0) // 2^51 - 2 + for i := 1; i < 50; i++ { // 2^100 - 2^50 + t1.Square(&t1) + } + t1.Multiply(&t1, &t0) // 2^100 - 1 + t2.Square(&t1) // 2^101 - 2 + for i := 1; i < 100; i++ { // 2^200 - 2^100 + t2.Square(&t2) + } + t1.Multiply(&t2, &t1) // 2^200 - 1 + t1.Square(&t1) // 2^201 - 2 + for i := 1; i < 50; i++ { // 2^250 - 2^50 + t1.Square(&t1) + } + t0.Multiply(&t1, &t0) // 2^250 - 1 + t0.Square(&t0) // 2^251 - 2 + t0.Square(&t0) // 2^252 - 4 + return v.Multiply(&t0, x) // 2^252 - 3 -> x^(2^252-3) +} + +// sqrtM1 is 2^((p-1)/4), which squared is equal to -1 by Euler's Criterion. +var sqrtM1 = &Element{1718705420411056, 234908883556509, + 2233514472574048, 2117202627021982, 765476049583133} + +// SqrtRatio sets r to the non-negative square root of the ratio of u and v. +// +// If u/v is square, SqrtRatio returns r and 1. If u/v is not square, SqrtRatio +// sets r according to Section 4.3 of draft-irtf-cfrg-ristretto255-decaf448-00, +// and returns r and 0. +func (r *Element) SqrtRatio(u, v *Element) (R *Element, wasSquare int) { + t0 := new(Element) + + // r = (u * v3) * (u * v7)^((p-5)/8) + v2 := new(Element).Square(v) + uv3 := new(Element).Multiply(u, t0.Multiply(v2, v)) + uv7 := new(Element).Multiply(uv3, t0.Square(v2)) + rr := new(Element).Multiply(uv3, t0.Pow22523(uv7)) + + check := new(Element).Multiply(v, t0.Square(rr)) // check = v * r^2 + + uNeg := new(Element).Negate(u) + correctSignSqrt := check.Equal(u) + flippedSignSqrt := check.Equal(uNeg) + flippedSignSqrtI := check.Equal(t0.Multiply(uNeg, sqrtM1)) + + rPrime := new(Element).Multiply(rr, sqrtM1) // r_prime = SQRT_M1 * r + // r = CT_SELECT(r_prime IF flipped_sign_sqrt | flipped_sign_sqrt_i ELSE r) + rr.Select(rPrime, rr, flippedSignSqrt|flippedSignSqrtI) + + r.Absolute(rr) // Choose the nonnegative square root. + return r, correctSignSqrt | flippedSignSqrt +} diff --git a/vendor/filippo.io/edwards25519/field/fe_amd64.go b/vendor/filippo.io/edwards25519/field/fe_amd64.go new file mode 100644 index 0000000..edcf163 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_amd64.go @@ -0,0 +1,16 @@ +// Code generated by command: go run fe_amd64_asm.go -out ../fe_amd64.s -stubs ../fe_amd64.go -pkg field. DO NOT EDIT. + +//go:build amd64 && gc && !purego +// +build amd64,gc,!purego + +package field + +// feMul sets out = a * b. It works like feMulGeneric. +// +//go:noescape +func feMul(out *Element, a *Element, b *Element) + +// feSquare sets out = a * a. It works like feSquareGeneric. +// +//go:noescape +func feSquare(out *Element, a *Element) diff --git a/vendor/filippo.io/edwards25519/field/fe_amd64.s b/vendor/filippo.io/edwards25519/field/fe_amd64.s new file mode 100644 index 0000000..293f013 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_amd64.s @@ -0,0 +1,379 @@ +// Code generated by command: go run fe_amd64_asm.go -out ../fe_amd64.s -stubs ../fe_amd64.go -pkg field. DO NOT EDIT. + +//go:build amd64 && gc && !purego +// +build amd64,gc,!purego + +#include "textflag.h" + +// func feMul(out *Element, a *Element, b *Element) +TEXT ·feMul(SB), NOSPLIT, $0-24 + MOVQ a+8(FP), CX + MOVQ b+16(FP), BX + + // r0 = a0×b0 + MOVQ (CX), AX + MULQ (BX) + MOVQ AX, DI + MOVQ DX, SI + + // r0 += 19×a1×b4 + MOVQ 8(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 32(BX) + ADDQ AX, DI + ADCQ DX, SI + + // r0 += 19×a2×b3 + MOVQ 16(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 24(BX) + ADDQ AX, DI + ADCQ DX, SI + + // r0 += 19×a3×b2 + MOVQ 24(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 16(BX) + ADDQ AX, DI + ADCQ DX, SI + + // r0 += 19×a4×b1 + MOVQ 32(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 8(BX) + ADDQ AX, DI + ADCQ DX, SI + + // r1 = a0×b1 + MOVQ (CX), AX + MULQ 8(BX) + MOVQ AX, R9 + MOVQ DX, R8 + + // r1 += a1×b0 + MOVQ 8(CX), AX + MULQ (BX) + ADDQ AX, R9 + ADCQ DX, R8 + + // r1 += 19×a2×b4 + MOVQ 16(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 32(BX) + ADDQ AX, R9 + ADCQ DX, R8 + + // r1 += 19×a3×b3 + MOVQ 24(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 24(BX) + ADDQ AX, R9 + ADCQ DX, R8 + + // r1 += 19×a4×b2 + MOVQ 32(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 16(BX) + ADDQ AX, R9 + ADCQ DX, R8 + + // r2 = a0×b2 + MOVQ (CX), AX + MULQ 16(BX) + MOVQ AX, R11 + MOVQ DX, R10 + + // r2 += a1×b1 + MOVQ 8(CX), AX + MULQ 8(BX) + ADDQ AX, R11 + ADCQ DX, R10 + + // r2 += a2×b0 + MOVQ 16(CX), AX + MULQ (BX) + ADDQ AX, R11 + ADCQ DX, R10 + + // r2 += 19×a3×b4 + MOVQ 24(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 32(BX) + ADDQ AX, R11 + ADCQ DX, R10 + + // r2 += 19×a4×b3 + MOVQ 32(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 24(BX) + ADDQ AX, R11 + ADCQ DX, R10 + + // r3 = a0×b3 + MOVQ (CX), AX + MULQ 24(BX) + MOVQ AX, R13 + MOVQ DX, R12 + + // r3 += a1×b2 + MOVQ 8(CX), AX + MULQ 16(BX) + ADDQ AX, R13 + ADCQ DX, R12 + + // r3 += a2×b1 + MOVQ 16(CX), AX + MULQ 8(BX) + ADDQ AX, R13 + ADCQ DX, R12 + + // r3 += a3×b0 + MOVQ 24(CX), AX + MULQ (BX) + ADDQ AX, R13 + ADCQ DX, R12 + + // r3 += 19×a4×b4 + MOVQ 32(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 32(BX) + ADDQ AX, R13 + ADCQ DX, R12 + + // r4 = a0×b4 + MOVQ (CX), AX + MULQ 32(BX) + MOVQ AX, R15 + MOVQ DX, R14 + + // r4 += a1×b3 + MOVQ 8(CX), AX + MULQ 24(BX) + ADDQ AX, R15 + ADCQ DX, R14 + + // r4 += a2×b2 + MOVQ 16(CX), AX + MULQ 16(BX) + ADDQ AX, R15 + ADCQ DX, R14 + + // r4 += a3×b1 + MOVQ 24(CX), AX + MULQ 8(BX) + ADDQ AX, R15 + ADCQ DX, R14 + + // r4 += a4×b0 + MOVQ 32(CX), AX + MULQ (BX) + ADDQ AX, R15 + ADCQ DX, R14 + + // First reduction chain + MOVQ $0x0007ffffffffffff, AX + SHLQ $0x0d, DI, SI + SHLQ $0x0d, R9, R8 + SHLQ $0x0d, R11, R10 + SHLQ $0x0d, R13, R12 + SHLQ $0x0d, R15, R14 + ANDQ AX, DI + IMUL3Q $0x13, R14, R14 + ADDQ R14, DI + ANDQ AX, R9 + ADDQ SI, R9 + ANDQ AX, R11 + ADDQ R8, R11 + ANDQ AX, R13 + ADDQ R10, R13 + ANDQ AX, R15 + ADDQ R12, R15 + + // Second reduction chain (carryPropagate) + MOVQ DI, SI + SHRQ $0x33, SI + MOVQ R9, R8 + SHRQ $0x33, R8 + MOVQ R11, R10 + SHRQ $0x33, R10 + MOVQ R13, R12 + SHRQ $0x33, R12 + MOVQ R15, R14 + SHRQ $0x33, R14 + ANDQ AX, DI + IMUL3Q $0x13, R14, R14 + ADDQ R14, DI + ANDQ AX, R9 + ADDQ SI, R9 + ANDQ AX, R11 + ADDQ R8, R11 + ANDQ AX, R13 + ADDQ R10, R13 + ANDQ AX, R15 + ADDQ R12, R15 + + // Store output + MOVQ out+0(FP), AX + MOVQ DI, (AX) + MOVQ R9, 8(AX) + MOVQ R11, 16(AX) + MOVQ R13, 24(AX) + MOVQ R15, 32(AX) + RET + +// func feSquare(out *Element, a *Element) +TEXT ·feSquare(SB), NOSPLIT, $0-16 + MOVQ a+8(FP), CX + + // r0 = l0×l0 + MOVQ (CX), AX + MULQ (CX) + MOVQ AX, SI + MOVQ DX, BX + + // r0 += 38×l1×l4 + MOVQ 8(CX), AX + IMUL3Q $0x26, AX, AX + MULQ 32(CX) + ADDQ AX, SI + ADCQ DX, BX + + // r0 += 38×l2×l3 + MOVQ 16(CX), AX + IMUL3Q $0x26, AX, AX + MULQ 24(CX) + ADDQ AX, SI + ADCQ DX, BX + + // r1 = 2×l0×l1 + MOVQ (CX), AX + SHLQ $0x01, AX + MULQ 8(CX) + MOVQ AX, R8 + MOVQ DX, DI + + // r1 += 38×l2×l4 + MOVQ 16(CX), AX + IMUL3Q $0x26, AX, AX + MULQ 32(CX) + ADDQ AX, R8 + ADCQ DX, DI + + // r1 += 19×l3×l3 + MOVQ 24(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 24(CX) + ADDQ AX, R8 + ADCQ DX, DI + + // r2 = 2×l0×l2 + MOVQ (CX), AX + SHLQ $0x01, AX + MULQ 16(CX) + MOVQ AX, R10 + MOVQ DX, R9 + + // r2 += l1×l1 + MOVQ 8(CX), AX + MULQ 8(CX) + ADDQ AX, R10 + ADCQ DX, R9 + + // r2 += 38×l3×l4 + MOVQ 24(CX), AX + IMUL3Q $0x26, AX, AX + MULQ 32(CX) + ADDQ AX, R10 + ADCQ DX, R9 + + // r3 = 2×l0×l3 + MOVQ (CX), AX + SHLQ $0x01, AX + MULQ 24(CX) + MOVQ AX, R12 + MOVQ DX, R11 + + // r3 += 2×l1×l2 + MOVQ 8(CX), AX + IMUL3Q $0x02, AX, AX + MULQ 16(CX) + ADDQ AX, R12 + ADCQ DX, R11 + + // r3 += 19×l4×l4 + MOVQ 32(CX), AX + IMUL3Q $0x13, AX, AX + MULQ 32(CX) + ADDQ AX, R12 + ADCQ DX, R11 + + // r4 = 2×l0×l4 + MOVQ (CX), AX + SHLQ $0x01, AX + MULQ 32(CX) + MOVQ AX, R14 + MOVQ DX, R13 + + // r4 += 2×l1×l3 + MOVQ 8(CX), AX + IMUL3Q $0x02, AX, AX + MULQ 24(CX) + ADDQ AX, R14 + ADCQ DX, R13 + + // r4 += l2×l2 + MOVQ 16(CX), AX + MULQ 16(CX) + ADDQ AX, R14 + ADCQ DX, R13 + + // First reduction chain + MOVQ $0x0007ffffffffffff, AX + SHLQ $0x0d, SI, BX + SHLQ $0x0d, R8, DI + SHLQ $0x0d, R10, R9 + SHLQ $0x0d, R12, R11 + SHLQ $0x0d, R14, R13 + ANDQ AX, SI + IMUL3Q $0x13, R13, R13 + ADDQ R13, SI + ANDQ AX, R8 + ADDQ BX, R8 + ANDQ AX, R10 + ADDQ DI, R10 + ANDQ AX, R12 + ADDQ R9, R12 + ANDQ AX, R14 + ADDQ R11, R14 + + // Second reduction chain (carryPropagate) + MOVQ SI, BX + SHRQ $0x33, BX + MOVQ R8, DI + SHRQ $0x33, DI + MOVQ R10, R9 + SHRQ $0x33, R9 + MOVQ R12, R11 + SHRQ $0x33, R11 + MOVQ R14, R13 + SHRQ $0x33, R13 + ANDQ AX, SI + IMUL3Q $0x13, R13, R13 + ADDQ R13, SI + ANDQ AX, R8 + ADDQ BX, R8 + ANDQ AX, R10 + ADDQ DI, R10 + ANDQ AX, R12 + ADDQ R9, R12 + ANDQ AX, R14 + ADDQ R11, R14 + + // Store output + MOVQ out+0(FP), AX + MOVQ SI, (AX) + MOVQ R8, 8(AX) + MOVQ R10, 16(AX) + MOVQ R12, 24(AX) + MOVQ R14, 32(AX) + RET diff --git a/vendor/filippo.io/edwards25519/field/fe_amd64_noasm.go b/vendor/filippo.io/edwards25519/field/fe_amd64_noasm.go new file mode 100644 index 0000000..ddb6c9b --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_amd64_noasm.go @@ -0,0 +1,12 @@ +// Copyright (c) 2019 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. + +//go:build !amd64 || !gc || purego +// +build !amd64 !gc purego + +package field + +func feMul(v, x, y *Element) { feMulGeneric(v, x, y) } + +func feSquare(v, x *Element) { feSquareGeneric(v, x) } diff --git a/vendor/filippo.io/edwards25519/field/fe_arm64.go b/vendor/filippo.io/edwards25519/field/fe_arm64.go new file mode 100644 index 0000000..af459ef --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_arm64.go @@ -0,0 +1,16 @@ +// Copyright (c) 2020 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. + +//go:build arm64 && gc && !purego +// +build arm64,gc,!purego + +package field + +//go:noescape +func carryPropagate(v *Element) + +func (v *Element) carryPropagate() *Element { + carryPropagate(v) + return v +} diff --git a/vendor/filippo.io/edwards25519/field/fe_arm64.s b/vendor/filippo.io/edwards25519/field/fe_arm64.s new file mode 100644 index 0000000..3126a43 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_arm64.s @@ -0,0 +1,42 @@ +// Copyright (c) 2020 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. + +//go:build arm64 && gc && !purego + +#include "textflag.h" + +// carryPropagate works exactly like carryPropagateGeneric and uses the +// same AND, ADD, and LSR+MADD instructions emitted by the compiler, but +// avoids loading R0-R4 twice and uses LDP and STP. +// +// See https://golang.org/issues/43145 for the main compiler issue. +// +// func carryPropagate(v *Element) +TEXT ·carryPropagate(SB),NOFRAME|NOSPLIT,$0-8 + MOVD v+0(FP), R20 + + LDP 0(R20), (R0, R1) + LDP 16(R20), (R2, R3) + MOVD 32(R20), R4 + + AND $0x7ffffffffffff, R0, R10 + AND $0x7ffffffffffff, R1, R11 + AND $0x7ffffffffffff, R2, R12 + AND $0x7ffffffffffff, R3, R13 + AND $0x7ffffffffffff, R4, R14 + + ADD R0>>51, R11, R11 + ADD R1>>51, R12, R12 + ADD R2>>51, R13, R13 + ADD R3>>51, R14, R14 + // R4>>51 * 19 + R10 -> R10 + LSR $51, R4, R21 + MOVD $19, R22 + MADD R22, R10, R21, R10 + + STP (R10, R11), 0(R20) + STP (R12, R13), 16(R20) + MOVD R14, 32(R20) + + RET diff --git a/vendor/filippo.io/edwards25519/field/fe_arm64_noasm.go b/vendor/filippo.io/edwards25519/field/fe_arm64_noasm.go new file mode 100644 index 0000000..234a5b2 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_arm64_noasm.go @@ -0,0 +1,12 @@ +// Copyright (c) 2021 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. + +//go:build !arm64 || !gc || purego +// +build !arm64 !gc purego + +package field + +func (v *Element) carryPropagate() *Element { + return v.carryPropagateGeneric() +} diff --git a/vendor/filippo.io/edwards25519/field/fe_extra.go b/vendor/filippo.io/edwards25519/field/fe_extra.go new file mode 100644 index 0000000..1ef503b --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_extra.go @@ -0,0 +1,50 @@ +// Copyright (c) 2021 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 field + +import "errors" + +// This file contains additional functionality that is not included in the +// upstream crypto/ed25519/edwards25519/field package. + +// SetWideBytes sets v to x, where x is a 64-byte little-endian encoding, which +// is reduced modulo the field order. If x is not of the right length, +// SetWideBytes returns nil and an error, and the receiver is unchanged. +// +// SetWideBytes is not necessary to select a uniformly distributed value, and is +// only provided for compatibility: SetBytes can be used instead as the chance +// of bias is less than 2⁻²⁵⁰. +func (v *Element) SetWideBytes(x []byte) (*Element, error) { + if len(x) != 64 { + return nil, errors.New("edwards25519: invalid SetWideBytes input size") + } + + // Split the 64 bytes into two elements, and extract the most significant + // bit of each, which is ignored by SetBytes. + lo, _ := new(Element).SetBytes(x[:32]) + loMSB := uint64(x[31] >> 7) + hi, _ := new(Element).SetBytes(x[32:]) + hiMSB := uint64(x[63] >> 7) + + // The output we want is + // + // v = lo + loMSB * 2²⁵⁵ + hi * 2²⁵⁶ + hiMSB * 2⁵¹¹ + // + // which applying the reduction identity comes out to + // + // v = lo + loMSB * 19 + hi * 2 * 19 + hiMSB * 2 * 19² + // + // l0 will be the sum of a 52 bits value (lo.l0), plus a 5 bits value + // (loMSB * 19), a 6 bits value (hi.l0 * 2 * 19), and a 10 bits value + // (hiMSB * 2 * 19²), so it fits in a uint64. + + v.l0 = lo.l0 + loMSB*19 + hi.l0*2*19 + hiMSB*2*19*19 + v.l1 = lo.l1 + hi.l1*2*19 + v.l2 = lo.l2 + hi.l2*2*19 + v.l3 = lo.l3 + hi.l3*2*19 + v.l4 = lo.l4 + hi.l4*2*19 + + return v.carryPropagate(), nil +} diff --git a/vendor/filippo.io/edwards25519/field/fe_generic.go b/vendor/filippo.io/edwards25519/field/fe_generic.go new file mode 100644 index 0000000..86f5fd9 --- /dev/null +++ b/vendor/filippo.io/edwards25519/field/fe_generic.go @@ -0,0 +1,266 @@ +// Copyright (c) 2017 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 field + +import "math/bits" + +// uint128 holds a 128-bit number as two 64-bit limbs, for use with the +// bits.Mul64 and bits.Add64 intrinsics. +type uint128 struct { + lo, hi uint64 +} + +// mul64 returns a * b. +func mul64(a, b uint64) uint128 { + hi, lo := bits.Mul64(a, b) + return uint128{lo, hi} +} + +// addMul64 returns v + a * b. +func addMul64(v uint128, a, b uint64) uint128 { + hi, lo := bits.Mul64(a, b) + lo, c := bits.Add64(lo, v.lo, 0) + hi, _ = bits.Add64(hi, v.hi, c) + return uint128{lo, hi} +} + +// shiftRightBy51 returns a >> 51. a is assumed to be at most 115 bits. +func shiftRightBy51(a uint128) uint64 { + return (a.hi << (64 - 51)) | (a.lo >> 51) +} + +func feMulGeneric(v, a, b *Element) { + a0 := a.l0 + a1 := a.l1 + a2 := a.l2 + a3 := a.l3 + a4 := a.l4 + + b0 := b.l0 + b1 := b.l1 + b2 := b.l2 + b3 := b.l3 + b4 := b.l4 + + // Limb multiplication works like pen-and-paper columnar multiplication, but + // with 51-bit limbs instead of digits. + // + // a4 a3 a2 a1 a0 x + // b4 b3 b2 b1 b0 = + // ------------------------ + // a4b0 a3b0 a2b0 a1b0 a0b0 + + // a4b1 a3b1 a2b1 a1b1 a0b1 + + // a4b2 a3b2 a2b2 a1b2 a0b2 + + // a4b3 a3b3 a2b3 a1b3 a0b3 + + // a4b4 a3b4 a2b4 a1b4 a0b4 = + // ---------------------------------------------- + // r8 r7 r6 r5 r4 r3 r2 r1 r0 + // + // We can then use the reduction identity (a * 2²⁵⁵ + b = a * 19 + b) to + // reduce the limbs that would overflow 255 bits. r5 * 2²⁵⁵ becomes 19 * r5, + // r6 * 2³⁰⁶ becomes 19 * r6 * 2⁵¹, etc. + // + // Reduction can be carried out simultaneously to multiplication. For + // example, we do not compute r5: whenever the result of a multiplication + // belongs to r5, like a1b4, we multiply it by 19 and add the result to r0. + // + // a4b0 a3b0 a2b0 a1b0 a0b0 + + // a3b1 a2b1 a1b1 a0b1 19×a4b1 + + // a2b2 a1b2 a0b2 19×a4b2 19×a3b2 + + // a1b3 a0b3 19×a4b3 19×a3b3 19×a2b3 + + // a0b4 19×a4b4 19×a3b4 19×a2b4 19×a1b4 = + // -------------------------------------- + // r4 r3 r2 r1 r0 + // + // Finally we add up the columns into wide, overlapping limbs. + + a1_19 := a1 * 19 + a2_19 := a2 * 19 + a3_19 := a3 * 19 + a4_19 := a4 * 19 + + // r0 = a0×b0 + 19×(a1×b4 + a2×b3 + a3×b2 + a4×b1) + r0 := mul64(a0, b0) + r0 = addMul64(r0, a1_19, b4) + r0 = addMul64(r0, a2_19, b3) + r0 = addMul64(r0, a3_19, b2) + r0 = addMul64(r0, a4_19, b1) + + // r1 = a0×b1 + a1×b0 + 19×(a2×b4 + a3×b3 + a4×b2) + r1 := mul64(a0, b1) + r1 = addMul64(r1, a1, b0) + r1 = addMul64(r1, a2_19, b4) + r1 = addMul64(r1, a3_19, b3) + r1 = addMul64(r1, a4_19, b2) + + // r2 = a0×b2 + a1×b1 + a2×b0 + 19×(a3×b4 + a4×b3) + r2 := mul64(a0, b2) + r2 = addMul64(r2, a1, b1) + r2 = addMul64(r2, a2, b0) + r2 = addMul64(r2, a3_19, b4) + r2 = addMul64(r2, a4_19, b3) + + // r3 = a0×b3 + a1×b2 + a2×b1 + a3×b0 + 19×a4×b4 + r3 := mul64(a0, b3) + r3 = addMul64(r3, a1, b2) + r3 = addMul64(r3, a2, b1) + r3 = addMul64(r3, a3, b0) + r3 = addMul64(r3, a4_19, b4) + + // r4 = a0×b4 + a1×b3 + a2×b2 + a3×b1 + a4×b0 + r4 := mul64(a0, b4) + r4 = addMul64(r4, a1, b3) + r4 = addMul64(r4, a2, b2) + r4 = addMul64(r4, a3, b1) + r4 = addMul64(r4, a4, b0) + + // After the multiplication, we need to reduce (carry) the five coefficients + // to obtain a result with limbs that are at most slightly larger than 2⁵¹, + // to respect the Element invariant. + // + // Overall, the reduction works the same as carryPropagate, except with + // wider inputs: we take the carry for each coefficient by shifting it right + // by 51, and add it to the limb above it. The top carry is multiplied by 19 + // according to the reduction identity and added to the lowest limb. + // + // The largest coefficient (r0) will be at most 111 bits, which guarantees + // that all carries are at most 111 - 51 = 60 bits, which fits in a uint64. + // + // r0 = a0×b0 + 19×(a1×b4 + a2×b3 + a3×b2 + a4×b1) + // r0 < 2⁵²×2⁵² + 19×(2⁵²×2⁵² + 2⁵²×2⁵² + 2⁵²×2⁵² + 2⁵²×2⁵²) + // r0 < (1 + 19 × 4) × 2⁵² × 2⁵² + // r0 < 2⁷ × 2⁵² × 2⁵² + // r0 < 2¹¹¹ + // + // Moreover, the top coefficient (r4) is at most 107 bits, so c4 is at most + // 56 bits, and c4 * 19 is at most 61 bits, which again fits in a uint64 and + // allows us to easily apply the reduction identity. + // + // r4 = a0×b4 + a1×b3 + a2×b2 + a3×b1 + a4×b0 + // r4 < 5 × 2⁵² × 2⁵² + // r4 < 2¹⁰⁷ + // + + c0 := shiftRightBy51(r0) + c1 := shiftRightBy51(r1) + c2 := shiftRightBy51(r2) + c3 := shiftRightBy51(r3) + c4 := shiftRightBy51(r4) + + rr0 := r0.lo&maskLow51Bits + c4*19 + rr1 := r1.lo&maskLow51Bits + c0 + rr2 := r2.lo&maskLow51Bits + c1 + rr3 := r3.lo&maskLow51Bits + c2 + rr4 := r4.lo&maskLow51Bits + c3 + + // Now all coefficients fit into 64-bit registers but are still too large to + // be passed around as an Element. We therefore do one last carry chain, + // where the carries will be small enough to fit in the wiggle room above 2⁵¹. + *v = Element{rr0, rr1, rr2, rr3, rr4} + v.carryPropagate() +} + +func feSquareGeneric(v, a *Element) { + l0 := a.l0 + l1 := a.l1 + l2 := a.l2 + l3 := a.l3 + l4 := a.l4 + + // Squaring works precisely like multiplication above, but thanks to its + // symmetry we get to group a few terms together. + // + // l4 l3 l2 l1 l0 x + // l4 l3 l2 l1 l0 = + // ------------------------ + // l4l0 l3l0 l2l0 l1l0 l0l0 + + // l4l1 l3l1 l2l1 l1l1 l0l1 + + // l4l2 l3l2 l2l2 l1l2 l0l2 + + // l4l3 l3l3 l2l3 l1l3 l0l3 + + // l4l4 l3l4 l2l4 l1l4 l0l4 = + // ---------------------------------------------- + // r8 r7 r6 r5 r4 r3 r2 r1 r0 + // + // l4l0 l3l0 l2l0 l1l0 l0l0 + + // l3l1 l2l1 l1l1 l0l1 19×l4l1 + + // l2l2 l1l2 l0l2 19×l4l2 19×l3l2 + + // l1l3 l0l3 19×l4l3 19×l3l3 19×l2l3 + + // l0l4 19×l4l4 19×l3l4 19×l2l4 19×l1l4 = + // -------------------------------------- + // r4 r3 r2 r1 r0 + // + // With precomputed 2×, 19×, and 2×19× terms, we can compute each limb with + // only three Mul64 and four Add64, instead of five and eight. + + l0_2 := l0 * 2 + l1_2 := l1 * 2 + + l1_38 := l1 * 38 + l2_38 := l2 * 38 + l3_38 := l3 * 38 + + l3_19 := l3 * 19 + l4_19 := l4 * 19 + + // r0 = l0×l0 + 19×(l1×l4 + l2×l3 + l3×l2 + l4×l1) = l0×l0 + 19×2×(l1×l4 + l2×l3) + r0 := mul64(l0, l0) + r0 = addMul64(r0, l1_38, l4) + r0 = addMul64(r0, l2_38, l3) + + // r1 = l0×l1 + l1×l0 + 19×(l2×l4 + l3×l3 + l4×l2) = 2×l0×l1 + 19×2×l2×l4 + 19×l3×l3 + r1 := mul64(l0_2, l1) + r1 = addMul64(r1, l2_38, l4) + r1 = addMul64(r1, l3_19, l3) + + // r2 = l0×l2 + l1×l1 + l2×l0 + 19×(l3×l4 + l4×l3) = 2×l0×l2 + l1×l1 + 19×2×l3×l4 + r2 := mul64(l0_2, l2) + r2 = addMul64(r2, l1, l1) + r2 = addMul64(r2, l3_38, l4) + + // r3 = l0×l3 + l1×l2 + l2×l1 + l3×l0 + 19×l4×l4 = 2×l0×l3 + 2×l1×l2 + 19×l4×l4 + r3 := mul64(l0_2, l3) + r3 = addMul64(r3, l1_2, l2) + r3 = addMul64(r3, l4_19, l4) + + // r4 = l0×l4 + l1×l3 + l2×l2 + l3×l1 + l4×l0 = 2×l0×l4 + 2×l1×l3 + l2×l2 + r4 := mul64(l0_2, l4) + r4 = addMul64(r4, l1_2, l3) + r4 = addMul64(r4, l2, l2) + + c0 := shiftRightBy51(r0) + c1 := shiftRightBy51(r1) + c2 := shiftRightBy51(r2) + c3 := shiftRightBy51(r3) + c4 := shiftRightBy51(r4) + + rr0 := r0.lo&maskLow51Bits + c4*19 + rr1 := r1.lo&maskLow51Bits + c0 + rr2 := r2.lo&maskLow51Bits + c1 + rr3 := r3.lo&maskLow51Bits + c2 + rr4 := r4.lo&maskLow51Bits + c3 + + *v = Element{rr0, rr1, rr2, rr3, rr4} + v.carryPropagate() +} + +// carryPropagateGeneric brings the limbs below 52 bits by applying the reduction +// identity (a * 2²⁵⁵ + b = a * 19 + b) to the l4 carry. +func (v *Element) carryPropagateGeneric() *Element { + c0 := v.l0 >> 51 + c1 := v.l1 >> 51 + c2 := v.l2 >> 51 + c3 := v.l3 >> 51 + c4 := v.l4 >> 51 + + // c4 is at most 64 - 51 = 13 bits, so c4*19 is at most 18 bits, and + // the final l0 will be at most 52 bits. Similarly for the rest. + v.l0 = v.l0&maskLow51Bits + c4*19 + v.l1 = v.l1&maskLow51Bits + c0 + v.l2 = v.l2&maskLow51Bits + c1 + v.l3 = v.l3&maskLow51Bits + c2 + v.l4 = v.l4&maskLow51Bits + c3 + + return v +} diff --git a/vendor/filippo.io/edwards25519/scalar.go b/vendor/filippo.io/edwards25519/scalar.go new file mode 100644 index 0000000..3fd1653 --- /dev/null +++ b/vendor/filippo.io/edwards25519/scalar.go @@ -0,0 +1,343 @@ +// Copyright (c) 2016 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 edwards25519 + +import ( + "encoding/binary" + "errors" +) + +// A Scalar is an integer modulo +// +// l = 2^252 + 27742317777372353535851937790883648493 +// +// which is the prime order of the edwards25519 group. +// +// This type works similarly to math/big.Int, and all arguments and +// receivers are allowed to alias. +// +// The zero value is a valid zero element. +type Scalar struct { + // s is the scalar in the Montgomery domain, in the format of the + // fiat-crypto implementation. + s fiatScalarMontgomeryDomainFieldElement +} + +// The field implementation in scalar_fiat.go is generated by the fiat-crypto +// project (https://github.com/mit-plv/fiat-crypto) at version v0.0.9 (23d2dbc) +// from a formally verified model. +// +// fiat-crypto code comes under the following license. +// +// Copyright (c) 2015-2020 The fiat-crypto Authors. All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// 1. Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// +// THIS SOFTWARE IS PROVIDED BY the fiat-crypto authors "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, +// Inc. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// + +// NewScalar returns a new zero Scalar. +func NewScalar() *Scalar { + return &Scalar{} +} + +// MultiplyAdd sets s = x * y + z mod l, and returns s. It is equivalent to +// using Multiply and then Add. +func (s *Scalar) MultiplyAdd(x, y, z *Scalar) *Scalar { + // Make a copy of z in case it aliases s. + zCopy := new(Scalar).Set(z) + return s.Multiply(x, y).Add(s, zCopy) +} + +// Add sets s = x + y mod l, and returns s. +func (s *Scalar) Add(x, y *Scalar) *Scalar { + // s = 1 * x + y mod l + fiatScalarAdd(&s.s, &x.s, &y.s) + return s +} + +// Subtract sets s = x - y mod l, and returns s. +func (s *Scalar) Subtract(x, y *Scalar) *Scalar { + // s = -1 * y + x mod l + fiatScalarSub(&s.s, &x.s, &y.s) + return s +} + +// Negate sets s = -x mod l, and returns s. +func (s *Scalar) Negate(x *Scalar) *Scalar { + // s = -1 * x + 0 mod l + fiatScalarOpp(&s.s, &x.s) + return s +} + +// Multiply sets s = x * y mod l, and returns s. +func (s *Scalar) Multiply(x, y *Scalar) *Scalar { + // s = x * y + 0 mod l + fiatScalarMul(&s.s, &x.s, &y.s) + return s +} + +// Set sets s = x, and returns s. +func (s *Scalar) Set(x *Scalar) *Scalar { + *s = *x + return s +} + +// SetUniformBytes sets s = x mod l, where x is a 64-byte little-endian integer. +// If x is not of the right length, SetUniformBytes returns nil and an error, +// and the receiver is unchanged. +// +// SetUniformBytes can be used to set s to a uniformly distributed value given +// 64 uniformly distributed random bytes. +func (s *Scalar) SetUniformBytes(x []byte) (*Scalar, error) { + if len(x) != 64 { + return nil, errors.New("edwards25519: invalid SetUniformBytes input length") + } + + // We have a value x of 512 bits, but our fiatScalarFromBytes function + // expects an input lower than l, which is a little over 252 bits. + // + // Instead of writing a reduction function that operates on wider inputs, we + // can interpret x as the sum of three shorter values a, b, and c. + // + // x = a + b * 2^168 + c * 2^336 mod l + // + // We then precompute 2^168 and 2^336 modulo l, and perform the reduction + // with two multiplications and two additions. + + s.setShortBytes(x[:21]) + t := new(Scalar).setShortBytes(x[21:42]) + s.Add(s, t.Multiply(t, scalarTwo168)) + t.setShortBytes(x[42:]) + s.Add(s, t.Multiply(t, scalarTwo336)) + + return s, nil +} + +// scalarTwo168 and scalarTwo336 are 2^168 and 2^336 modulo l, encoded as a +// fiatScalarMontgomeryDomainFieldElement, which is a little-endian 4-limb value +// in the 2^256 Montgomery domain. +var scalarTwo168 = &Scalar{s: [4]uint64{0x5b8ab432eac74798, 0x38afddd6de59d5d7, + 0xa2c131b399411b7c, 0x6329a7ed9ce5a30}} +var scalarTwo336 = &Scalar{s: [4]uint64{0xbd3d108e2b35ecc5, 0x5c3a3718bdf9c90b, + 0x63aa97a331b4f2ee, 0x3d217f5be65cb5c}} + +// setShortBytes sets s = x mod l, where x is a little-endian integer shorter +// than 32 bytes. +func (s *Scalar) setShortBytes(x []byte) *Scalar { + if len(x) >= 32 { + panic("edwards25519: internal error: setShortBytes called with a long string") + } + var buf [32]byte + copy(buf[:], x) + fiatScalarFromBytes((*[4]uint64)(&s.s), &buf) + fiatScalarToMontgomery(&s.s, (*fiatScalarNonMontgomeryDomainFieldElement)(&s.s)) + return s +} + +// SetCanonicalBytes sets s = x, where x is a 32-byte little-endian encoding of +// s, and returns s. If x is not a canonical encoding of s, SetCanonicalBytes +// returns nil and an error, and the receiver is unchanged. +func (s *Scalar) SetCanonicalBytes(x []byte) (*Scalar, error) { + if len(x) != 32 { + return nil, errors.New("invalid scalar length") + } + if !isReduced(x) { + return nil, errors.New("invalid scalar encoding") + } + + fiatScalarFromBytes((*[4]uint64)(&s.s), (*[32]byte)(x)) + fiatScalarToMontgomery(&s.s, (*fiatScalarNonMontgomeryDomainFieldElement)(&s.s)) + + return s, nil +} + +// scalarMinusOneBytes is l - 1 in little endian. +var scalarMinusOneBytes = [32]byte{236, 211, 245, 92, 26, 99, 18, 88, 214, 156, 247, 162, 222, 249, 222, 20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16} + +// isReduced returns whether the given scalar in 32-byte little endian encoded +// form is reduced modulo l. +func isReduced(s []byte) bool { + if len(s) != 32 { + return false + } + + for i := len(s) - 1; i >= 0; i-- { + switch { + case s[i] > scalarMinusOneBytes[i]: + return false + case s[i] < scalarMinusOneBytes[i]: + return true + } + } + return true +} + +// SetBytesWithClamping applies the buffer pruning described in RFC 8032, +// Section 5.1.5 (also known as clamping) and sets s to the result. The input +// must be 32 bytes, and it is not modified. If x is not of the right length, +// SetBytesWithClamping returns nil and an error, and the receiver is unchanged. +// +// Note that since Scalar values are always reduced modulo the prime order of +// the curve, the resulting value will not preserve any of the cofactor-clearing +// properties that clamping is meant to provide. It will however work as +// expected as long as it is applied to points on the prime order subgroup, like +// in Ed25519. In fact, it is lost to history why RFC 8032 adopted the +// irrelevant RFC 7748 clamping, but it is now required for compatibility. +func (s *Scalar) SetBytesWithClamping(x []byte) (*Scalar, error) { + // The description above omits the purpose of the high bits of the clamping + // for brevity, but those are also lost to reductions, and are also + // irrelevant to edwards25519 as they protect against a specific + // implementation bug that was once observed in a generic Montgomery ladder. + if len(x) != 32 { + return nil, errors.New("edwards25519: invalid SetBytesWithClamping input length") + } + + // We need to use the wide reduction from SetUniformBytes, since clamping + // sets the 2^254 bit, making the value higher than the order. + var wideBytes [64]byte + copy(wideBytes[:], x[:]) + wideBytes[0] &= 248 + wideBytes[31] &= 63 + wideBytes[31] |= 64 + return s.SetUniformBytes(wideBytes[:]) +} + +// Bytes returns the canonical 32-byte little-endian encoding of s. +func (s *Scalar) Bytes() []byte { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. + var encoded [32]byte + return s.bytes(&encoded) +} + +func (s *Scalar) bytes(out *[32]byte) []byte { + var ss fiatScalarNonMontgomeryDomainFieldElement + fiatScalarFromMontgomery(&ss, &s.s) + fiatScalarToBytes(out, (*[4]uint64)(&ss)) + return out[:] +} + +// Equal returns 1 if s and t are equal, and 0 otherwise. +func (s *Scalar) Equal(t *Scalar) int { + var diff fiatScalarMontgomeryDomainFieldElement + fiatScalarSub(&diff, &s.s, &t.s) + var nonzero uint64 + fiatScalarNonzero(&nonzero, (*[4]uint64)(&diff)) + nonzero |= nonzero >> 32 + nonzero |= nonzero >> 16 + nonzero |= nonzero >> 8 + nonzero |= nonzero >> 4 + nonzero |= nonzero >> 2 + nonzero |= nonzero >> 1 + return int(^nonzero) & 1 +} + +// nonAdjacentForm computes a width-w non-adjacent form for this scalar. +// +// w must be between 2 and 8, or nonAdjacentForm will panic. +func (s *Scalar) nonAdjacentForm(w uint) [256]int8 { + // This implementation is adapted from the one + // in curve25519-dalek and is documented there: + // https://github.com/dalek-cryptography/curve25519-dalek/blob/f630041af28e9a405255f98a8a93adca18e4315b/src/scalar.rs#L800-L871 + b := s.Bytes() + if b[31] > 127 { + panic("scalar has high bit set illegally") + } + if w < 2 { + panic("w must be at least 2 by the definition of NAF") + } else if w > 8 { + panic("NAF digits must fit in int8") + } + + var naf [256]int8 + var digits [5]uint64 + + for i := 0; i < 4; i++ { + digits[i] = binary.LittleEndian.Uint64(b[i*8:]) + } + + width := uint64(1 << w) + windowMask := uint64(width - 1) + + pos := uint(0) + carry := uint64(0) + for pos < 256 { + indexU64 := pos / 64 + indexBit := pos % 64 + var bitBuf uint64 + if indexBit < 64-w { + // This window's bits are contained in a single u64 + bitBuf = digits[indexU64] >> indexBit + } else { + // Combine the current 64 bits with bits from the next 64 + bitBuf = (digits[indexU64] >> indexBit) | (digits[1+indexU64] << (64 - indexBit)) + } + + // Add carry into the current window + window := carry + (bitBuf & windowMask) + + if window&1 == 0 { + // If the window value is even, preserve the carry and continue. + // Why is the carry preserved? + // If carry == 0 and window & 1 == 0, + // then the next carry should be 0 + // If carry == 1 and window & 1 == 0, + // then bit_buf & 1 == 1 so the next carry should be 1 + pos += 1 + continue + } + + if window < width/2 { + carry = 0 + naf[pos] = int8(window) + } else { + carry = 1 + naf[pos] = int8(window) - int8(width) + } + + pos += w + } + return naf +} + +func (s *Scalar) signedRadix16() [64]int8 { + b := s.Bytes() + if b[31] > 127 { + panic("scalar has high bit set illegally") + } + + var digits [64]int8 + + // Compute unsigned radix-16 digits: + for i := 0; i < 32; i++ { + digits[2*i] = int8(b[i] & 15) + digits[2*i+1] = int8((b[i] >> 4) & 15) + } + + // Recenter coefficients: + for i := 0; i < 63; i++ { + carry := (digits[i] + 8) >> 4 + digits[i] -= carry << 4 + digits[i+1] += carry + } + + return digits +} diff --git a/vendor/filippo.io/edwards25519/scalar_fiat.go b/vendor/filippo.io/edwards25519/scalar_fiat.go new file mode 100644 index 0000000..2e5782b --- /dev/null +++ b/vendor/filippo.io/edwards25519/scalar_fiat.go @@ -0,0 +1,1147 @@ +// Code generated by Fiat Cryptography. DO NOT EDIT. +// +// Autogenerated: word_by_word_montgomery --lang Go --cmovznz-by-mul --relax-primitive-carry-to-bitwidth 32,64 --public-function-case camelCase --public-type-case camelCase --private-function-case camelCase --private-type-case camelCase --doc-text-before-function-name '' --doc-newline-before-package-declaration --doc-prepend-header 'Code generated by Fiat Cryptography. DO NOT EDIT.' --package-name edwards25519 Scalar 64 '2^252 + 27742317777372353535851937790883648493' mul add sub opp nonzero from_montgomery to_montgomery to_bytes from_bytes +// +// curve description: Scalar +// +// machine_wordsize = 64 (from "64") +// +// requested operations: mul, add, sub, opp, nonzero, from_montgomery, to_montgomery, to_bytes, from_bytes +// +// m = 0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed (from "2^252 + 27742317777372353535851937790883648493") +// +// +// +// NOTE: In addition to the bounds specified above each function, all +// +// functions synthesized for this Montgomery arithmetic require the +// +// input to be strictly less than the prime modulus (m), and also +// +// require the input to be in the unique saturated representation. +// +// All functions also ensure that these two properties are true of +// +// return values. +// +// +// +// Computed values: +// +// eval z = z[0] + (z[1] << 64) + (z[2] << 128) + (z[3] << 192) +// +// bytes_eval z = z[0] + (z[1] << 8) + (z[2] << 16) + (z[3] << 24) + (z[4] << 32) + (z[5] << 40) + (z[6] << 48) + (z[7] << 56) + (z[8] << 64) + (z[9] << 72) + (z[10] << 80) + (z[11] << 88) + (z[12] << 96) + (z[13] << 104) + (z[14] << 112) + (z[15] << 120) + (z[16] << 128) + (z[17] << 136) + (z[18] << 144) + (z[19] << 152) + (z[20] << 160) + (z[21] << 168) + (z[22] << 176) + (z[23] << 184) + (z[24] << 192) + (z[25] << 200) + (z[26] << 208) + (z[27] << 216) + (z[28] << 224) + (z[29] << 232) + (z[30] << 240) + (z[31] << 248) +// +// twos_complement_eval z = let x1 := z[0] + (z[1] << 64) + (z[2] << 128) + (z[3] << 192) in +// +// if x1 & (2^256-1) < 2^255 then x1 & (2^256-1) else (x1 & (2^256-1)) - 2^256 + +package edwards25519 + +import "math/bits" + +type fiatScalarUint1 uint64 // We use uint64 instead of a more narrow type for performance reasons; see https://github.com/mit-plv/fiat-crypto/pull/1006#issuecomment-892625927 +type fiatScalarInt1 int64 // We use uint64 instead of a more narrow type for performance reasons; see https://github.com/mit-plv/fiat-crypto/pull/1006#issuecomment-892625927 + +// The type fiatScalarMontgomeryDomainFieldElement is a field element in the Montgomery domain. +// +// Bounds: [[0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff]] +type fiatScalarMontgomeryDomainFieldElement [4]uint64 + +// The type fiatScalarNonMontgomeryDomainFieldElement is a field element NOT in the Montgomery domain. +// +// Bounds: [[0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff]] +type fiatScalarNonMontgomeryDomainFieldElement [4]uint64 + +// fiatScalarCmovznzU64 is a single-word conditional move. +// +// Postconditions: +// +// out1 = (if arg1 = 0 then arg2 else arg3) +// +// Input Bounds: +// +// arg1: [0x0 ~> 0x1] +// arg2: [0x0 ~> 0xffffffffffffffff] +// arg3: [0x0 ~> 0xffffffffffffffff] +// +// Output Bounds: +// +// out1: [0x0 ~> 0xffffffffffffffff] +func fiatScalarCmovznzU64(out1 *uint64, arg1 fiatScalarUint1, arg2 uint64, arg3 uint64) { + x1 := (uint64(arg1) * 0xffffffffffffffff) + x2 := ((x1 & arg3) | ((^x1) & arg2)) + *out1 = x2 +} + +// fiatScalarMul multiplies two field elements in the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// 0 ≤ eval arg2 < m +// +// Postconditions: +// +// eval (from_montgomery out1) mod m = (eval (from_montgomery arg1) * eval (from_montgomery arg2)) mod m +// 0 ≤ eval out1 < m +func fiatScalarMul(out1 *fiatScalarMontgomeryDomainFieldElement, arg1 *fiatScalarMontgomeryDomainFieldElement, arg2 *fiatScalarMontgomeryDomainFieldElement) { + x1 := arg1[1] + x2 := arg1[2] + x3 := arg1[3] + x4 := arg1[0] + var x5 uint64 + var x6 uint64 + x6, x5 = bits.Mul64(x4, arg2[3]) + var x7 uint64 + var x8 uint64 + x8, x7 = bits.Mul64(x4, arg2[2]) + var x9 uint64 + var x10 uint64 + x10, x9 = bits.Mul64(x4, arg2[1]) + var x11 uint64 + var x12 uint64 + x12, x11 = bits.Mul64(x4, arg2[0]) + var x13 uint64 + var x14 uint64 + x13, x14 = bits.Add64(x12, x9, uint64(0x0)) + var x15 uint64 + var x16 uint64 + x15, x16 = bits.Add64(x10, x7, uint64(fiatScalarUint1(x14))) + var x17 uint64 + var x18 uint64 + x17, x18 = bits.Add64(x8, x5, uint64(fiatScalarUint1(x16))) + x19 := (uint64(fiatScalarUint1(x18)) + x6) + var x20 uint64 + _, x20 = bits.Mul64(x11, 0xd2b51da312547e1b) + var x22 uint64 + var x23 uint64 + x23, x22 = bits.Mul64(x20, 0x1000000000000000) + var x24 uint64 + var x25 uint64 + x25, x24 = bits.Mul64(x20, 0x14def9dea2f79cd6) + var x26 uint64 + var x27 uint64 + x27, x26 = bits.Mul64(x20, 0x5812631a5cf5d3ed) + var x28 uint64 + var x29 uint64 + x28, x29 = bits.Add64(x27, x24, uint64(0x0)) + x30 := (uint64(fiatScalarUint1(x29)) + x25) + var x32 uint64 + _, x32 = bits.Add64(x11, x26, uint64(0x0)) + var x33 uint64 + var x34 uint64 + x33, x34 = bits.Add64(x13, x28, uint64(fiatScalarUint1(x32))) + var x35 uint64 + var x36 uint64 + x35, x36 = bits.Add64(x15, x30, uint64(fiatScalarUint1(x34))) + var x37 uint64 + var x38 uint64 + x37, x38 = bits.Add64(x17, x22, uint64(fiatScalarUint1(x36))) + var x39 uint64 + var x40 uint64 + x39, x40 = bits.Add64(x19, x23, uint64(fiatScalarUint1(x38))) + var x41 uint64 + var x42 uint64 + x42, x41 = bits.Mul64(x1, arg2[3]) + var x43 uint64 + var x44 uint64 + x44, x43 = bits.Mul64(x1, arg2[2]) + var x45 uint64 + var x46 uint64 + x46, x45 = bits.Mul64(x1, arg2[1]) + var x47 uint64 + var x48 uint64 + x48, x47 = bits.Mul64(x1, arg2[0]) + var x49 uint64 + var x50 uint64 + x49, x50 = bits.Add64(x48, x45, uint64(0x0)) + var x51 uint64 + var x52 uint64 + x51, x52 = bits.Add64(x46, x43, uint64(fiatScalarUint1(x50))) + var x53 uint64 + var x54 uint64 + x53, x54 = bits.Add64(x44, x41, uint64(fiatScalarUint1(x52))) + x55 := (uint64(fiatScalarUint1(x54)) + x42) + var x56 uint64 + var x57 uint64 + x56, x57 = bits.Add64(x33, x47, uint64(0x0)) + var x58 uint64 + var x59 uint64 + x58, x59 = bits.Add64(x35, x49, uint64(fiatScalarUint1(x57))) + var x60 uint64 + var x61 uint64 + x60, x61 = bits.Add64(x37, x51, uint64(fiatScalarUint1(x59))) + var x62 uint64 + var x63 uint64 + x62, x63 = bits.Add64(x39, x53, uint64(fiatScalarUint1(x61))) + var x64 uint64 + var x65 uint64 + x64, x65 = bits.Add64(uint64(fiatScalarUint1(x40)), x55, uint64(fiatScalarUint1(x63))) + var x66 uint64 + _, x66 = bits.Mul64(x56, 0xd2b51da312547e1b) + var x68 uint64 + var x69 uint64 + x69, x68 = bits.Mul64(x66, 0x1000000000000000) + var x70 uint64 + var x71 uint64 + x71, x70 = bits.Mul64(x66, 0x14def9dea2f79cd6) + var x72 uint64 + var x73 uint64 + x73, x72 = bits.Mul64(x66, 0x5812631a5cf5d3ed) + var x74 uint64 + var x75 uint64 + x74, x75 = bits.Add64(x73, x70, uint64(0x0)) + x76 := (uint64(fiatScalarUint1(x75)) + x71) + var x78 uint64 + _, x78 = bits.Add64(x56, x72, uint64(0x0)) + var x79 uint64 + var x80 uint64 + x79, x80 = bits.Add64(x58, x74, uint64(fiatScalarUint1(x78))) + var x81 uint64 + var x82 uint64 + x81, x82 = bits.Add64(x60, x76, uint64(fiatScalarUint1(x80))) + var x83 uint64 + var x84 uint64 + x83, x84 = bits.Add64(x62, x68, uint64(fiatScalarUint1(x82))) + var x85 uint64 + var x86 uint64 + x85, x86 = bits.Add64(x64, x69, uint64(fiatScalarUint1(x84))) + x87 := (uint64(fiatScalarUint1(x86)) + uint64(fiatScalarUint1(x65))) + var x88 uint64 + var x89 uint64 + x89, x88 = bits.Mul64(x2, arg2[3]) + var x90 uint64 + var x91 uint64 + x91, x90 = bits.Mul64(x2, arg2[2]) + var x92 uint64 + var x93 uint64 + x93, x92 = bits.Mul64(x2, arg2[1]) + var x94 uint64 + var x95 uint64 + x95, x94 = bits.Mul64(x2, arg2[0]) + var x96 uint64 + var x97 uint64 + x96, x97 = bits.Add64(x95, x92, uint64(0x0)) + var x98 uint64 + var x99 uint64 + x98, x99 = bits.Add64(x93, x90, uint64(fiatScalarUint1(x97))) + var x100 uint64 + var x101 uint64 + x100, x101 = bits.Add64(x91, x88, uint64(fiatScalarUint1(x99))) + x102 := (uint64(fiatScalarUint1(x101)) + x89) + var x103 uint64 + var x104 uint64 + x103, x104 = bits.Add64(x79, x94, uint64(0x0)) + var x105 uint64 + var x106 uint64 + x105, x106 = bits.Add64(x81, x96, uint64(fiatScalarUint1(x104))) + var x107 uint64 + var x108 uint64 + x107, x108 = bits.Add64(x83, x98, uint64(fiatScalarUint1(x106))) + var x109 uint64 + var x110 uint64 + x109, x110 = bits.Add64(x85, x100, uint64(fiatScalarUint1(x108))) + var x111 uint64 + var x112 uint64 + x111, x112 = bits.Add64(x87, x102, uint64(fiatScalarUint1(x110))) + var x113 uint64 + _, x113 = bits.Mul64(x103, 0xd2b51da312547e1b) + var x115 uint64 + var x116 uint64 + x116, x115 = bits.Mul64(x113, 0x1000000000000000) + var x117 uint64 + var x118 uint64 + x118, x117 = bits.Mul64(x113, 0x14def9dea2f79cd6) + var x119 uint64 + var x120 uint64 + x120, x119 = bits.Mul64(x113, 0x5812631a5cf5d3ed) + var x121 uint64 + var x122 uint64 + x121, x122 = bits.Add64(x120, x117, uint64(0x0)) + x123 := (uint64(fiatScalarUint1(x122)) + x118) + var x125 uint64 + _, x125 = bits.Add64(x103, x119, uint64(0x0)) + var x126 uint64 + var x127 uint64 + x126, x127 = bits.Add64(x105, x121, uint64(fiatScalarUint1(x125))) + var x128 uint64 + var x129 uint64 + x128, x129 = bits.Add64(x107, x123, uint64(fiatScalarUint1(x127))) + var x130 uint64 + var x131 uint64 + x130, x131 = bits.Add64(x109, x115, uint64(fiatScalarUint1(x129))) + var x132 uint64 + var x133 uint64 + x132, x133 = bits.Add64(x111, x116, uint64(fiatScalarUint1(x131))) + x134 := (uint64(fiatScalarUint1(x133)) + uint64(fiatScalarUint1(x112))) + var x135 uint64 + var x136 uint64 + x136, x135 = bits.Mul64(x3, arg2[3]) + var x137 uint64 + var x138 uint64 + x138, x137 = bits.Mul64(x3, arg2[2]) + var x139 uint64 + var x140 uint64 + x140, x139 = bits.Mul64(x3, arg2[1]) + var x141 uint64 + var x142 uint64 + x142, x141 = bits.Mul64(x3, arg2[0]) + var x143 uint64 + var x144 uint64 + x143, x144 = bits.Add64(x142, x139, uint64(0x0)) + var x145 uint64 + var x146 uint64 + x145, x146 = bits.Add64(x140, x137, uint64(fiatScalarUint1(x144))) + var x147 uint64 + var x148 uint64 + x147, x148 = bits.Add64(x138, x135, uint64(fiatScalarUint1(x146))) + x149 := (uint64(fiatScalarUint1(x148)) + x136) + var x150 uint64 + var x151 uint64 + x150, x151 = bits.Add64(x126, x141, uint64(0x0)) + var x152 uint64 + var x153 uint64 + x152, x153 = bits.Add64(x128, x143, uint64(fiatScalarUint1(x151))) + var x154 uint64 + var x155 uint64 + x154, x155 = bits.Add64(x130, x145, uint64(fiatScalarUint1(x153))) + var x156 uint64 + var x157 uint64 + x156, x157 = bits.Add64(x132, x147, uint64(fiatScalarUint1(x155))) + var x158 uint64 + var x159 uint64 + x158, x159 = bits.Add64(x134, x149, uint64(fiatScalarUint1(x157))) + var x160 uint64 + _, x160 = bits.Mul64(x150, 0xd2b51da312547e1b) + var x162 uint64 + var x163 uint64 + x163, x162 = bits.Mul64(x160, 0x1000000000000000) + var x164 uint64 + var x165 uint64 + x165, x164 = bits.Mul64(x160, 0x14def9dea2f79cd6) + var x166 uint64 + var x167 uint64 + x167, x166 = bits.Mul64(x160, 0x5812631a5cf5d3ed) + var x168 uint64 + var x169 uint64 + x168, x169 = bits.Add64(x167, x164, uint64(0x0)) + x170 := (uint64(fiatScalarUint1(x169)) + x165) + var x172 uint64 + _, x172 = bits.Add64(x150, x166, uint64(0x0)) + var x173 uint64 + var x174 uint64 + x173, x174 = bits.Add64(x152, x168, uint64(fiatScalarUint1(x172))) + var x175 uint64 + var x176 uint64 + x175, x176 = bits.Add64(x154, x170, uint64(fiatScalarUint1(x174))) + var x177 uint64 + var x178 uint64 + x177, x178 = bits.Add64(x156, x162, uint64(fiatScalarUint1(x176))) + var x179 uint64 + var x180 uint64 + x179, x180 = bits.Add64(x158, x163, uint64(fiatScalarUint1(x178))) + x181 := (uint64(fiatScalarUint1(x180)) + uint64(fiatScalarUint1(x159))) + var x182 uint64 + var x183 uint64 + x182, x183 = bits.Sub64(x173, 0x5812631a5cf5d3ed, uint64(0x0)) + var x184 uint64 + var x185 uint64 + x184, x185 = bits.Sub64(x175, 0x14def9dea2f79cd6, uint64(fiatScalarUint1(x183))) + var x186 uint64 + var x187 uint64 + x186, x187 = bits.Sub64(x177, uint64(0x0), uint64(fiatScalarUint1(x185))) + var x188 uint64 + var x189 uint64 + x188, x189 = bits.Sub64(x179, 0x1000000000000000, uint64(fiatScalarUint1(x187))) + var x191 uint64 + _, x191 = bits.Sub64(x181, uint64(0x0), uint64(fiatScalarUint1(x189))) + var x192 uint64 + fiatScalarCmovznzU64(&x192, fiatScalarUint1(x191), x182, x173) + var x193 uint64 + fiatScalarCmovznzU64(&x193, fiatScalarUint1(x191), x184, x175) + var x194 uint64 + fiatScalarCmovznzU64(&x194, fiatScalarUint1(x191), x186, x177) + var x195 uint64 + fiatScalarCmovznzU64(&x195, fiatScalarUint1(x191), x188, x179) + out1[0] = x192 + out1[1] = x193 + out1[2] = x194 + out1[3] = x195 +} + +// fiatScalarAdd adds two field elements in the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// 0 ≤ eval arg2 < m +// +// Postconditions: +// +// eval (from_montgomery out1) mod m = (eval (from_montgomery arg1) + eval (from_montgomery arg2)) mod m +// 0 ≤ eval out1 < m +func fiatScalarAdd(out1 *fiatScalarMontgomeryDomainFieldElement, arg1 *fiatScalarMontgomeryDomainFieldElement, arg2 *fiatScalarMontgomeryDomainFieldElement) { + var x1 uint64 + var x2 uint64 + x1, x2 = bits.Add64(arg1[0], arg2[0], uint64(0x0)) + var x3 uint64 + var x4 uint64 + x3, x4 = bits.Add64(arg1[1], arg2[1], uint64(fiatScalarUint1(x2))) + var x5 uint64 + var x6 uint64 + x5, x6 = bits.Add64(arg1[2], arg2[2], uint64(fiatScalarUint1(x4))) + var x7 uint64 + var x8 uint64 + x7, x8 = bits.Add64(arg1[3], arg2[3], uint64(fiatScalarUint1(x6))) + var x9 uint64 + var x10 uint64 + x9, x10 = bits.Sub64(x1, 0x5812631a5cf5d3ed, uint64(0x0)) + var x11 uint64 + var x12 uint64 + x11, x12 = bits.Sub64(x3, 0x14def9dea2f79cd6, uint64(fiatScalarUint1(x10))) + var x13 uint64 + var x14 uint64 + x13, x14 = bits.Sub64(x5, uint64(0x0), uint64(fiatScalarUint1(x12))) + var x15 uint64 + var x16 uint64 + x15, x16 = bits.Sub64(x7, 0x1000000000000000, uint64(fiatScalarUint1(x14))) + var x18 uint64 + _, x18 = bits.Sub64(uint64(fiatScalarUint1(x8)), uint64(0x0), uint64(fiatScalarUint1(x16))) + var x19 uint64 + fiatScalarCmovznzU64(&x19, fiatScalarUint1(x18), x9, x1) + var x20 uint64 + fiatScalarCmovznzU64(&x20, fiatScalarUint1(x18), x11, x3) + var x21 uint64 + fiatScalarCmovznzU64(&x21, fiatScalarUint1(x18), x13, x5) + var x22 uint64 + fiatScalarCmovznzU64(&x22, fiatScalarUint1(x18), x15, x7) + out1[0] = x19 + out1[1] = x20 + out1[2] = x21 + out1[3] = x22 +} + +// fiatScalarSub subtracts two field elements in the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// 0 ≤ eval arg2 < m +// +// Postconditions: +// +// eval (from_montgomery out1) mod m = (eval (from_montgomery arg1) - eval (from_montgomery arg2)) mod m +// 0 ≤ eval out1 < m +func fiatScalarSub(out1 *fiatScalarMontgomeryDomainFieldElement, arg1 *fiatScalarMontgomeryDomainFieldElement, arg2 *fiatScalarMontgomeryDomainFieldElement) { + var x1 uint64 + var x2 uint64 + x1, x2 = bits.Sub64(arg1[0], arg2[0], uint64(0x0)) + var x3 uint64 + var x4 uint64 + x3, x4 = bits.Sub64(arg1[1], arg2[1], uint64(fiatScalarUint1(x2))) + var x5 uint64 + var x6 uint64 + x5, x6 = bits.Sub64(arg1[2], arg2[2], uint64(fiatScalarUint1(x4))) + var x7 uint64 + var x8 uint64 + x7, x8 = bits.Sub64(arg1[3], arg2[3], uint64(fiatScalarUint1(x6))) + var x9 uint64 + fiatScalarCmovznzU64(&x9, fiatScalarUint1(x8), uint64(0x0), 0xffffffffffffffff) + var x10 uint64 + var x11 uint64 + x10, x11 = bits.Add64(x1, (x9 & 0x5812631a5cf5d3ed), uint64(0x0)) + var x12 uint64 + var x13 uint64 + x12, x13 = bits.Add64(x3, (x9 & 0x14def9dea2f79cd6), uint64(fiatScalarUint1(x11))) + var x14 uint64 + var x15 uint64 + x14, x15 = bits.Add64(x5, uint64(0x0), uint64(fiatScalarUint1(x13))) + var x16 uint64 + x16, _ = bits.Add64(x7, (x9 & 0x1000000000000000), uint64(fiatScalarUint1(x15))) + out1[0] = x10 + out1[1] = x12 + out1[2] = x14 + out1[3] = x16 +} + +// fiatScalarOpp negates a field element in the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// +// Postconditions: +// +// eval (from_montgomery out1) mod m = -eval (from_montgomery arg1) mod m +// 0 ≤ eval out1 < m +func fiatScalarOpp(out1 *fiatScalarMontgomeryDomainFieldElement, arg1 *fiatScalarMontgomeryDomainFieldElement) { + var x1 uint64 + var x2 uint64 + x1, x2 = bits.Sub64(uint64(0x0), arg1[0], uint64(0x0)) + var x3 uint64 + var x4 uint64 + x3, x4 = bits.Sub64(uint64(0x0), arg1[1], uint64(fiatScalarUint1(x2))) + var x5 uint64 + var x6 uint64 + x5, x6 = bits.Sub64(uint64(0x0), arg1[2], uint64(fiatScalarUint1(x4))) + var x7 uint64 + var x8 uint64 + x7, x8 = bits.Sub64(uint64(0x0), arg1[3], uint64(fiatScalarUint1(x6))) + var x9 uint64 + fiatScalarCmovznzU64(&x9, fiatScalarUint1(x8), uint64(0x0), 0xffffffffffffffff) + var x10 uint64 + var x11 uint64 + x10, x11 = bits.Add64(x1, (x9 & 0x5812631a5cf5d3ed), uint64(0x0)) + var x12 uint64 + var x13 uint64 + x12, x13 = bits.Add64(x3, (x9 & 0x14def9dea2f79cd6), uint64(fiatScalarUint1(x11))) + var x14 uint64 + var x15 uint64 + x14, x15 = bits.Add64(x5, uint64(0x0), uint64(fiatScalarUint1(x13))) + var x16 uint64 + x16, _ = bits.Add64(x7, (x9 & 0x1000000000000000), uint64(fiatScalarUint1(x15))) + out1[0] = x10 + out1[1] = x12 + out1[2] = x14 + out1[3] = x16 +} + +// fiatScalarNonzero outputs a single non-zero word if the input is non-zero and zero otherwise. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// +// Postconditions: +// +// out1 = 0 ↔ eval (from_montgomery arg1) mod m = 0 +// +// Input Bounds: +// +// arg1: [[0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff]] +// +// Output Bounds: +// +// out1: [0x0 ~> 0xffffffffffffffff] +func fiatScalarNonzero(out1 *uint64, arg1 *[4]uint64) { + x1 := (arg1[0] | (arg1[1] | (arg1[2] | arg1[3]))) + *out1 = x1 +} + +// fiatScalarFromMontgomery translates a field element out of the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// +// Postconditions: +// +// eval out1 mod m = (eval arg1 * ((2^64)⁻¹ mod m)^4) mod m +// 0 ≤ eval out1 < m +func fiatScalarFromMontgomery(out1 *fiatScalarNonMontgomeryDomainFieldElement, arg1 *fiatScalarMontgomeryDomainFieldElement) { + x1 := arg1[0] + var x2 uint64 + _, x2 = bits.Mul64(x1, 0xd2b51da312547e1b) + var x4 uint64 + var x5 uint64 + x5, x4 = bits.Mul64(x2, 0x1000000000000000) + var x6 uint64 + var x7 uint64 + x7, x6 = bits.Mul64(x2, 0x14def9dea2f79cd6) + var x8 uint64 + var x9 uint64 + x9, x8 = bits.Mul64(x2, 0x5812631a5cf5d3ed) + var x10 uint64 + var x11 uint64 + x10, x11 = bits.Add64(x9, x6, uint64(0x0)) + var x13 uint64 + _, x13 = bits.Add64(x1, x8, uint64(0x0)) + var x14 uint64 + var x15 uint64 + x14, x15 = bits.Add64(uint64(0x0), x10, uint64(fiatScalarUint1(x13))) + var x16 uint64 + var x17 uint64 + x16, x17 = bits.Add64(x14, arg1[1], uint64(0x0)) + var x18 uint64 + _, x18 = bits.Mul64(x16, 0xd2b51da312547e1b) + var x20 uint64 + var x21 uint64 + x21, x20 = bits.Mul64(x18, 0x1000000000000000) + var x22 uint64 + var x23 uint64 + x23, x22 = bits.Mul64(x18, 0x14def9dea2f79cd6) + var x24 uint64 + var x25 uint64 + x25, x24 = bits.Mul64(x18, 0x5812631a5cf5d3ed) + var x26 uint64 + var x27 uint64 + x26, x27 = bits.Add64(x25, x22, uint64(0x0)) + var x29 uint64 + _, x29 = bits.Add64(x16, x24, uint64(0x0)) + var x30 uint64 + var x31 uint64 + x30, x31 = bits.Add64((uint64(fiatScalarUint1(x17)) + (uint64(fiatScalarUint1(x15)) + (uint64(fiatScalarUint1(x11)) + x7))), x26, uint64(fiatScalarUint1(x29))) + var x32 uint64 + var x33 uint64 + x32, x33 = bits.Add64(x4, (uint64(fiatScalarUint1(x27)) + x23), uint64(fiatScalarUint1(x31))) + var x34 uint64 + var x35 uint64 + x34, x35 = bits.Add64(x5, x20, uint64(fiatScalarUint1(x33))) + var x36 uint64 + var x37 uint64 + x36, x37 = bits.Add64(x30, arg1[2], uint64(0x0)) + var x38 uint64 + var x39 uint64 + x38, x39 = bits.Add64(x32, uint64(0x0), uint64(fiatScalarUint1(x37))) + var x40 uint64 + var x41 uint64 + x40, x41 = bits.Add64(x34, uint64(0x0), uint64(fiatScalarUint1(x39))) + var x42 uint64 + _, x42 = bits.Mul64(x36, 0xd2b51da312547e1b) + var x44 uint64 + var x45 uint64 + x45, x44 = bits.Mul64(x42, 0x1000000000000000) + var x46 uint64 + var x47 uint64 + x47, x46 = bits.Mul64(x42, 0x14def9dea2f79cd6) + var x48 uint64 + var x49 uint64 + x49, x48 = bits.Mul64(x42, 0x5812631a5cf5d3ed) + var x50 uint64 + var x51 uint64 + x50, x51 = bits.Add64(x49, x46, uint64(0x0)) + var x53 uint64 + _, x53 = bits.Add64(x36, x48, uint64(0x0)) + var x54 uint64 + var x55 uint64 + x54, x55 = bits.Add64(x38, x50, uint64(fiatScalarUint1(x53))) + var x56 uint64 + var x57 uint64 + x56, x57 = bits.Add64(x40, (uint64(fiatScalarUint1(x51)) + x47), uint64(fiatScalarUint1(x55))) + var x58 uint64 + var x59 uint64 + x58, x59 = bits.Add64((uint64(fiatScalarUint1(x41)) + (uint64(fiatScalarUint1(x35)) + x21)), x44, uint64(fiatScalarUint1(x57))) + var x60 uint64 + var x61 uint64 + x60, x61 = bits.Add64(x54, arg1[3], uint64(0x0)) + var x62 uint64 + var x63 uint64 + x62, x63 = bits.Add64(x56, uint64(0x0), uint64(fiatScalarUint1(x61))) + var x64 uint64 + var x65 uint64 + x64, x65 = bits.Add64(x58, uint64(0x0), uint64(fiatScalarUint1(x63))) + var x66 uint64 + _, x66 = bits.Mul64(x60, 0xd2b51da312547e1b) + var x68 uint64 + var x69 uint64 + x69, x68 = bits.Mul64(x66, 0x1000000000000000) + var x70 uint64 + var x71 uint64 + x71, x70 = bits.Mul64(x66, 0x14def9dea2f79cd6) + var x72 uint64 + var x73 uint64 + x73, x72 = bits.Mul64(x66, 0x5812631a5cf5d3ed) + var x74 uint64 + var x75 uint64 + x74, x75 = bits.Add64(x73, x70, uint64(0x0)) + var x77 uint64 + _, x77 = bits.Add64(x60, x72, uint64(0x0)) + var x78 uint64 + var x79 uint64 + x78, x79 = bits.Add64(x62, x74, uint64(fiatScalarUint1(x77))) + var x80 uint64 + var x81 uint64 + x80, x81 = bits.Add64(x64, (uint64(fiatScalarUint1(x75)) + x71), uint64(fiatScalarUint1(x79))) + var x82 uint64 + var x83 uint64 + x82, x83 = bits.Add64((uint64(fiatScalarUint1(x65)) + (uint64(fiatScalarUint1(x59)) + x45)), x68, uint64(fiatScalarUint1(x81))) + x84 := (uint64(fiatScalarUint1(x83)) + x69) + var x85 uint64 + var x86 uint64 + x85, x86 = bits.Sub64(x78, 0x5812631a5cf5d3ed, uint64(0x0)) + var x87 uint64 + var x88 uint64 + x87, x88 = bits.Sub64(x80, 0x14def9dea2f79cd6, uint64(fiatScalarUint1(x86))) + var x89 uint64 + var x90 uint64 + x89, x90 = bits.Sub64(x82, uint64(0x0), uint64(fiatScalarUint1(x88))) + var x91 uint64 + var x92 uint64 + x91, x92 = bits.Sub64(x84, 0x1000000000000000, uint64(fiatScalarUint1(x90))) + var x94 uint64 + _, x94 = bits.Sub64(uint64(0x0), uint64(0x0), uint64(fiatScalarUint1(x92))) + var x95 uint64 + fiatScalarCmovznzU64(&x95, fiatScalarUint1(x94), x85, x78) + var x96 uint64 + fiatScalarCmovznzU64(&x96, fiatScalarUint1(x94), x87, x80) + var x97 uint64 + fiatScalarCmovznzU64(&x97, fiatScalarUint1(x94), x89, x82) + var x98 uint64 + fiatScalarCmovznzU64(&x98, fiatScalarUint1(x94), x91, x84) + out1[0] = x95 + out1[1] = x96 + out1[2] = x97 + out1[3] = x98 +} + +// fiatScalarToMontgomery translates a field element into the Montgomery domain. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// +// Postconditions: +// +// eval (from_montgomery out1) mod m = eval arg1 mod m +// 0 ≤ eval out1 < m +func fiatScalarToMontgomery(out1 *fiatScalarMontgomeryDomainFieldElement, arg1 *fiatScalarNonMontgomeryDomainFieldElement) { + x1 := arg1[1] + x2 := arg1[2] + x3 := arg1[3] + x4 := arg1[0] + var x5 uint64 + var x6 uint64 + x6, x5 = bits.Mul64(x4, 0x399411b7c309a3d) + var x7 uint64 + var x8 uint64 + x8, x7 = bits.Mul64(x4, 0xceec73d217f5be65) + var x9 uint64 + var x10 uint64 + x10, x9 = bits.Mul64(x4, 0xd00e1ba768859347) + var x11 uint64 + var x12 uint64 + x12, x11 = bits.Mul64(x4, 0xa40611e3449c0f01) + var x13 uint64 + var x14 uint64 + x13, x14 = bits.Add64(x12, x9, uint64(0x0)) + var x15 uint64 + var x16 uint64 + x15, x16 = bits.Add64(x10, x7, uint64(fiatScalarUint1(x14))) + var x17 uint64 + var x18 uint64 + x17, x18 = bits.Add64(x8, x5, uint64(fiatScalarUint1(x16))) + var x19 uint64 + _, x19 = bits.Mul64(x11, 0xd2b51da312547e1b) + var x21 uint64 + var x22 uint64 + x22, x21 = bits.Mul64(x19, 0x1000000000000000) + var x23 uint64 + var x24 uint64 + x24, x23 = bits.Mul64(x19, 0x14def9dea2f79cd6) + var x25 uint64 + var x26 uint64 + x26, x25 = bits.Mul64(x19, 0x5812631a5cf5d3ed) + var x27 uint64 + var x28 uint64 + x27, x28 = bits.Add64(x26, x23, uint64(0x0)) + var x30 uint64 + _, x30 = bits.Add64(x11, x25, uint64(0x0)) + var x31 uint64 + var x32 uint64 + x31, x32 = bits.Add64(x13, x27, uint64(fiatScalarUint1(x30))) + var x33 uint64 + var x34 uint64 + x33, x34 = bits.Add64(x15, (uint64(fiatScalarUint1(x28)) + x24), uint64(fiatScalarUint1(x32))) + var x35 uint64 + var x36 uint64 + x35, x36 = bits.Add64(x17, x21, uint64(fiatScalarUint1(x34))) + var x37 uint64 + var x38 uint64 + x38, x37 = bits.Mul64(x1, 0x399411b7c309a3d) + var x39 uint64 + var x40 uint64 + x40, x39 = bits.Mul64(x1, 0xceec73d217f5be65) + var x41 uint64 + var x42 uint64 + x42, x41 = bits.Mul64(x1, 0xd00e1ba768859347) + var x43 uint64 + var x44 uint64 + x44, x43 = bits.Mul64(x1, 0xa40611e3449c0f01) + var x45 uint64 + var x46 uint64 + x45, x46 = bits.Add64(x44, x41, uint64(0x0)) + var x47 uint64 + var x48 uint64 + x47, x48 = bits.Add64(x42, x39, uint64(fiatScalarUint1(x46))) + var x49 uint64 + var x50 uint64 + x49, x50 = bits.Add64(x40, x37, uint64(fiatScalarUint1(x48))) + var x51 uint64 + var x52 uint64 + x51, x52 = bits.Add64(x31, x43, uint64(0x0)) + var x53 uint64 + var x54 uint64 + x53, x54 = bits.Add64(x33, x45, uint64(fiatScalarUint1(x52))) + var x55 uint64 + var x56 uint64 + x55, x56 = bits.Add64(x35, x47, uint64(fiatScalarUint1(x54))) + var x57 uint64 + var x58 uint64 + x57, x58 = bits.Add64(((uint64(fiatScalarUint1(x36)) + (uint64(fiatScalarUint1(x18)) + x6)) + x22), x49, uint64(fiatScalarUint1(x56))) + var x59 uint64 + _, x59 = bits.Mul64(x51, 0xd2b51da312547e1b) + var x61 uint64 + var x62 uint64 + x62, x61 = bits.Mul64(x59, 0x1000000000000000) + var x63 uint64 + var x64 uint64 + x64, x63 = bits.Mul64(x59, 0x14def9dea2f79cd6) + var x65 uint64 + var x66 uint64 + x66, x65 = bits.Mul64(x59, 0x5812631a5cf5d3ed) + var x67 uint64 + var x68 uint64 + x67, x68 = bits.Add64(x66, x63, uint64(0x0)) + var x70 uint64 + _, x70 = bits.Add64(x51, x65, uint64(0x0)) + var x71 uint64 + var x72 uint64 + x71, x72 = bits.Add64(x53, x67, uint64(fiatScalarUint1(x70))) + var x73 uint64 + var x74 uint64 + x73, x74 = bits.Add64(x55, (uint64(fiatScalarUint1(x68)) + x64), uint64(fiatScalarUint1(x72))) + var x75 uint64 + var x76 uint64 + x75, x76 = bits.Add64(x57, x61, uint64(fiatScalarUint1(x74))) + var x77 uint64 + var x78 uint64 + x78, x77 = bits.Mul64(x2, 0x399411b7c309a3d) + var x79 uint64 + var x80 uint64 + x80, x79 = bits.Mul64(x2, 0xceec73d217f5be65) + var x81 uint64 + var x82 uint64 + x82, x81 = bits.Mul64(x2, 0xd00e1ba768859347) + var x83 uint64 + var x84 uint64 + x84, x83 = bits.Mul64(x2, 0xa40611e3449c0f01) + var x85 uint64 + var x86 uint64 + x85, x86 = bits.Add64(x84, x81, uint64(0x0)) + var x87 uint64 + var x88 uint64 + x87, x88 = bits.Add64(x82, x79, uint64(fiatScalarUint1(x86))) + var x89 uint64 + var x90 uint64 + x89, x90 = bits.Add64(x80, x77, uint64(fiatScalarUint1(x88))) + var x91 uint64 + var x92 uint64 + x91, x92 = bits.Add64(x71, x83, uint64(0x0)) + var x93 uint64 + var x94 uint64 + x93, x94 = bits.Add64(x73, x85, uint64(fiatScalarUint1(x92))) + var x95 uint64 + var x96 uint64 + x95, x96 = bits.Add64(x75, x87, uint64(fiatScalarUint1(x94))) + var x97 uint64 + var x98 uint64 + x97, x98 = bits.Add64(((uint64(fiatScalarUint1(x76)) + (uint64(fiatScalarUint1(x58)) + (uint64(fiatScalarUint1(x50)) + x38))) + x62), x89, uint64(fiatScalarUint1(x96))) + var x99 uint64 + _, x99 = bits.Mul64(x91, 0xd2b51da312547e1b) + var x101 uint64 + var x102 uint64 + x102, x101 = bits.Mul64(x99, 0x1000000000000000) + var x103 uint64 + var x104 uint64 + x104, x103 = bits.Mul64(x99, 0x14def9dea2f79cd6) + var x105 uint64 + var x106 uint64 + x106, x105 = bits.Mul64(x99, 0x5812631a5cf5d3ed) + var x107 uint64 + var x108 uint64 + x107, x108 = bits.Add64(x106, x103, uint64(0x0)) + var x110 uint64 + _, x110 = bits.Add64(x91, x105, uint64(0x0)) + var x111 uint64 + var x112 uint64 + x111, x112 = bits.Add64(x93, x107, uint64(fiatScalarUint1(x110))) + var x113 uint64 + var x114 uint64 + x113, x114 = bits.Add64(x95, (uint64(fiatScalarUint1(x108)) + x104), uint64(fiatScalarUint1(x112))) + var x115 uint64 + var x116 uint64 + x115, x116 = bits.Add64(x97, x101, uint64(fiatScalarUint1(x114))) + var x117 uint64 + var x118 uint64 + x118, x117 = bits.Mul64(x3, 0x399411b7c309a3d) + var x119 uint64 + var x120 uint64 + x120, x119 = bits.Mul64(x3, 0xceec73d217f5be65) + var x121 uint64 + var x122 uint64 + x122, x121 = bits.Mul64(x3, 0xd00e1ba768859347) + var x123 uint64 + var x124 uint64 + x124, x123 = bits.Mul64(x3, 0xa40611e3449c0f01) + var x125 uint64 + var x126 uint64 + x125, x126 = bits.Add64(x124, x121, uint64(0x0)) + var x127 uint64 + var x128 uint64 + x127, x128 = bits.Add64(x122, x119, uint64(fiatScalarUint1(x126))) + var x129 uint64 + var x130 uint64 + x129, x130 = bits.Add64(x120, x117, uint64(fiatScalarUint1(x128))) + var x131 uint64 + var x132 uint64 + x131, x132 = bits.Add64(x111, x123, uint64(0x0)) + var x133 uint64 + var x134 uint64 + x133, x134 = bits.Add64(x113, x125, uint64(fiatScalarUint1(x132))) + var x135 uint64 + var x136 uint64 + x135, x136 = bits.Add64(x115, x127, uint64(fiatScalarUint1(x134))) + var x137 uint64 + var x138 uint64 + x137, x138 = bits.Add64(((uint64(fiatScalarUint1(x116)) + (uint64(fiatScalarUint1(x98)) + (uint64(fiatScalarUint1(x90)) + x78))) + x102), x129, uint64(fiatScalarUint1(x136))) + var x139 uint64 + _, x139 = bits.Mul64(x131, 0xd2b51da312547e1b) + var x141 uint64 + var x142 uint64 + x142, x141 = bits.Mul64(x139, 0x1000000000000000) + var x143 uint64 + var x144 uint64 + x144, x143 = bits.Mul64(x139, 0x14def9dea2f79cd6) + var x145 uint64 + var x146 uint64 + x146, x145 = bits.Mul64(x139, 0x5812631a5cf5d3ed) + var x147 uint64 + var x148 uint64 + x147, x148 = bits.Add64(x146, x143, uint64(0x0)) + var x150 uint64 + _, x150 = bits.Add64(x131, x145, uint64(0x0)) + var x151 uint64 + var x152 uint64 + x151, x152 = bits.Add64(x133, x147, uint64(fiatScalarUint1(x150))) + var x153 uint64 + var x154 uint64 + x153, x154 = bits.Add64(x135, (uint64(fiatScalarUint1(x148)) + x144), uint64(fiatScalarUint1(x152))) + var x155 uint64 + var x156 uint64 + x155, x156 = bits.Add64(x137, x141, uint64(fiatScalarUint1(x154))) + x157 := ((uint64(fiatScalarUint1(x156)) + (uint64(fiatScalarUint1(x138)) + (uint64(fiatScalarUint1(x130)) + x118))) + x142) + var x158 uint64 + var x159 uint64 + x158, x159 = bits.Sub64(x151, 0x5812631a5cf5d3ed, uint64(0x0)) + var x160 uint64 + var x161 uint64 + x160, x161 = bits.Sub64(x153, 0x14def9dea2f79cd6, uint64(fiatScalarUint1(x159))) + var x162 uint64 + var x163 uint64 + x162, x163 = bits.Sub64(x155, uint64(0x0), uint64(fiatScalarUint1(x161))) + var x164 uint64 + var x165 uint64 + x164, x165 = bits.Sub64(x157, 0x1000000000000000, uint64(fiatScalarUint1(x163))) + var x167 uint64 + _, x167 = bits.Sub64(uint64(0x0), uint64(0x0), uint64(fiatScalarUint1(x165))) + var x168 uint64 + fiatScalarCmovznzU64(&x168, fiatScalarUint1(x167), x158, x151) + var x169 uint64 + fiatScalarCmovznzU64(&x169, fiatScalarUint1(x167), x160, x153) + var x170 uint64 + fiatScalarCmovznzU64(&x170, fiatScalarUint1(x167), x162, x155) + var x171 uint64 + fiatScalarCmovznzU64(&x171, fiatScalarUint1(x167), x164, x157) + out1[0] = x168 + out1[1] = x169 + out1[2] = x170 + out1[3] = x171 +} + +// fiatScalarToBytes serializes a field element NOT in the Montgomery domain to bytes in little-endian order. +// +// Preconditions: +// +// 0 ≤ eval arg1 < m +// +// Postconditions: +// +// out1 = map (λ x, ⌊((eval arg1 mod m) mod 2^(8 * (x + 1))) / 2^(8 * x)⌋) [0..31] +// +// Input Bounds: +// +// arg1: [[0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0x1fffffffffffffff]] +// +// Output Bounds: +// +// out1: [[0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0x1f]] +func fiatScalarToBytes(out1 *[32]uint8, arg1 *[4]uint64) { + x1 := arg1[3] + x2 := arg1[2] + x3 := arg1[1] + x4 := arg1[0] + x5 := (uint8(x4) & 0xff) + x6 := (x4 >> 8) + x7 := (uint8(x6) & 0xff) + x8 := (x6 >> 8) + x9 := (uint8(x8) & 0xff) + x10 := (x8 >> 8) + x11 := (uint8(x10) & 0xff) + x12 := (x10 >> 8) + x13 := (uint8(x12) & 0xff) + x14 := (x12 >> 8) + x15 := (uint8(x14) & 0xff) + x16 := (x14 >> 8) + x17 := (uint8(x16) & 0xff) + x18 := uint8((x16 >> 8)) + x19 := (uint8(x3) & 0xff) + x20 := (x3 >> 8) + x21 := (uint8(x20) & 0xff) + x22 := (x20 >> 8) + x23 := (uint8(x22) & 0xff) + x24 := (x22 >> 8) + x25 := (uint8(x24) & 0xff) + x26 := (x24 >> 8) + x27 := (uint8(x26) & 0xff) + x28 := (x26 >> 8) + x29 := (uint8(x28) & 0xff) + x30 := (x28 >> 8) + x31 := (uint8(x30) & 0xff) + x32 := uint8((x30 >> 8)) + x33 := (uint8(x2) & 0xff) + x34 := (x2 >> 8) + x35 := (uint8(x34) & 0xff) + x36 := (x34 >> 8) + x37 := (uint8(x36) & 0xff) + x38 := (x36 >> 8) + x39 := (uint8(x38) & 0xff) + x40 := (x38 >> 8) + x41 := (uint8(x40) & 0xff) + x42 := (x40 >> 8) + x43 := (uint8(x42) & 0xff) + x44 := (x42 >> 8) + x45 := (uint8(x44) & 0xff) + x46 := uint8((x44 >> 8)) + x47 := (uint8(x1) & 0xff) + x48 := (x1 >> 8) + x49 := (uint8(x48) & 0xff) + x50 := (x48 >> 8) + x51 := (uint8(x50) & 0xff) + x52 := (x50 >> 8) + x53 := (uint8(x52) & 0xff) + x54 := (x52 >> 8) + x55 := (uint8(x54) & 0xff) + x56 := (x54 >> 8) + x57 := (uint8(x56) & 0xff) + x58 := (x56 >> 8) + x59 := (uint8(x58) & 0xff) + x60 := uint8((x58 >> 8)) + out1[0] = x5 + out1[1] = x7 + out1[2] = x9 + out1[3] = x11 + out1[4] = x13 + out1[5] = x15 + out1[6] = x17 + out1[7] = x18 + out1[8] = x19 + out1[9] = x21 + out1[10] = x23 + out1[11] = x25 + out1[12] = x27 + out1[13] = x29 + out1[14] = x31 + out1[15] = x32 + out1[16] = x33 + out1[17] = x35 + out1[18] = x37 + out1[19] = x39 + out1[20] = x41 + out1[21] = x43 + out1[22] = x45 + out1[23] = x46 + out1[24] = x47 + out1[25] = x49 + out1[26] = x51 + out1[27] = x53 + out1[28] = x55 + out1[29] = x57 + out1[30] = x59 + out1[31] = x60 +} + +// fiatScalarFromBytes deserializes a field element NOT in the Montgomery domain from bytes in little-endian order. +// +// Preconditions: +// +// 0 ≤ bytes_eval arg1 < m +// +// Postconditions: +// +// eval out1 mod m = bytes_eval arg1 mod m +// 0 ≤ eval out1 < m +// +// Input Bounds: +// +// arg1: [[0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0xff], [0x0 ~> 0x1f]] +// +// Output Bounds: +// +// out1: [[0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0xffffffffffffffff], [0x0 ~> 0x1fffffffffffffff]] +func fiatScalarFromBytes(out1 *[4]uint64, arg1 *[32]uint8) { + x1 := (uint64(arg1[31]) << 56) + x2 := (uint64(arg1[30]) << 48) + x3 := (uint64(arg1[29]) << 40) + x4 := (uint64(arg1[28]) << 32) + x5 := (uint64(arg1[27]) << 24) + x6 := (uint64(arg1[26]) << 16) + x7 := (uint64(arg1[25]) << 8) + x8 := arg1[24] + x9 := (uint64(arg1[23]) << 56) + x10 := (uint64(arg1[22]) << 48) + x11 := (uint64(arg1[21]) << 40) + x12 := (uint64(arg1[20]) << 32) + x13 := (uint64(arg1[19]) << 24) + x14 := (uint64(arg1[18]) << 16) + x15 := (uint64(arg1[17]) << 8) + x16 := arg1[16] + x17 := (uint64(arg1[15]) << 56) + x18 := (uint64(arg1[14]) << 48) + x19 := (uint64(arg1[13]) << 40) + x20 := (uint64(arg1[12]) << 32) + x21 := (uint64(arg1[11]) << 24) + x22 := (uint64(arg1[10]) << 16) + x23 := (uint64(arg1[9]) << 8) + x24 := arg1[8] + x25 := (uint64(arg1[7]) << 56) + x26 := (uint64(arg1[6]) << 48) + x27 := (uint64(arg1[5]) << 40) + x28 := (uint64(arg1[4]) << 32) + x29 := (uint64(arg1[3]) << 24) + x30 := (uint64(arg1[2]) << 16) + x31 := (uint64(arg1[1]) << 8) + x32 := arg1[0] + x33 := (x31 + uint64(x32)) + x34 := (x30 + x33) + x35 := (x29 + x34) + x36 := (x28 + x35) + x37 := (x27 + x36) + x38 := (x26 + x37) + x39 := (x25 + x38) + x40 := (x23 + uint64(x24)) + x41 := (x22 + x40) + x42 := (x21 + x41) + x43 := (x20 + x42) + x44 := (x19 + x43) + x45 := (x18 + x44) + x46 := (x17 + x45) + x47 := (x15 + uint64(x16)) + x48 := (x14 + x47) + x49 := (x13 + x48) + x50 := (x12 + x49) + x51 := (x11 + x50) + x52 := (x10 + x51) + x53 := (x9 + x52) + x54 := (x7 + uint64(x8)) + x55 := (x6 + x54) + x56 := (x5 + x55) + x57 := (x4 + x56) + x58 := (x3 + x57) + x59 := (x2 + x58) + x60 := (x1 + x59) + out1[0] = x39 + out1[1] = x46 + out1[2] = x53 + out1[3] = x60 +} diff --git a/vendor/filippo.io/edwards25519/scalarmult.go b/vendor/filippo.io/edwards25519/scalarmult.go new file mode 100644 index 0000000..f7ca3ce --- /dev/null +++ b/vendor/filippo.io/edwards25519/scalarmult.go @@ -0,0 +1,214 @@ +// Copyright (c) 2019 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 edwards25519 + +import "sync" + +// basepointTable is a set of 32 affineLookupTables, where table i is generated +// from 256i * basepoint. It is precomputed the first time it's used. +func basepointTable() *[32]affineLookupTable { + basepointTablePrecomp.initOnce.Do(func() { + p := NewGeneratorPoint() + for i := 0; i < 32; i++ { + basepointTablePrecomp.table[i].FromP3(p) + for j := 0; j < 8; j++ { + p.Add(p, p) + } + } + }) + return &basepointTablePrecomp.table +} + +var basepointTablePrecomp struct { + table [32]affineLookupTable + initOnce sync.Once +} + +// ScalarBaseMult sets v = x * B, where B is the canonical generator, and +// returns v. +// +// The scalar multiplication is done in constant time. +func (v *Point) ScalarBaseMult(x *Scalar) *Point { + basepointTable := basepointTable() + + // Write x = sum(x_i * 16^i) so x*B = sum( B*x_i*16^i ) + // as described in the Ed25519 paper + // + // Group even and odd coefficients + // x*B = x_0*16^0*B + x_2*16^2*B + ... + x_62*16^62*B + // + x_1*16^1*B + x_3*16^3*B + ... + x_63*16^63*B + // x*B = x_0*16^0*B + x_2*16^2*B + ... + x_62*16^62*B + // + 16*( x_1*16^0*B + x_3*16^2*B + ... + x_63*16^62*B) + // + // We use a lookup table for each i to get x_i*16^(2*i)*B + // and do four doublings to multiply by 16. + digits := x.signedRadix16() + + multiple := &affineCached{} + tmp1 := &projP1xP1{} + tmp2 := &projP2{} + + // Accumulate the odd components first + v.Set(NewIdentityPoint()) + for i := 1; i < 64; i += 2 { + basepointTable[i/2].SelectInto(multiple, digits[i]) + tmp1.AddAffine(v, multiple) + v.fromP1xP1(tmp1) + } + + // Multiply by 16 + tmp2.FromP3(v) // tmp2 = v in P2 coords + tmp1.Double(tmp2) // tmp1 = 2*v in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 2*v in P2 coords + tmp1.Double(tmp2) // tmp1 = 4*v in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 4*v in P2 coords + tmp1.Double(tmp2) // tmp1 = 8*v in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 8*v in P2 coords + tmp1.Double(tmp2) // tmp1 = 16*v in P1xP1 coords + v.fromP1xP1(tmp1) // now v = 16*(odd components) + + // Accumulate the even components + for i := 0; i < 64; i += 2 { + basepointTable[i/2].SelectInto(multiple, digits[i]) + tmp1.AddAffine(v, multiple) + v.fromP1xP1(tmp1) + } + + return v +} + +// ScalarMult sets v = x * q, and returns v. +// +// The scalar multiplication is done in constant time. +func (v *Point) ScalarMult(x *Scalar, q *Point) *Point { + checkInitialized(q) + + var table projLookupTable + table.FromP3(q) + + // Write x = sum(x_i * 16^i) + // so x*Q = sum( Q*x_i*16^i ) + // = Q*x_0 + 16*(Q*x_1 + 16*( ... + Q*x_63) ... ) + // <------compute inside out--------- + // + // We use the lookup table to get the x_i*Q values + // and do four doublings to compute 16*Q + digits := x.signedRadix16() + + // Unwrap first loop iteration to save computing 16*identity + multiple := &projCached{} + tmp1 := &projP1xP1{} + tmp2 := &projP2{} + table.SelectInto(multiple, digits[63]) + + v.Set(NewIdentityPoint()) + tmp1.Add(v, multiple) // tmp1 = x_63*Q in P1xP1 coords + for i := 62; i >= 0; i-- { + tmp2.FromP1xP1(tmp1) // tmp2 = (prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 2*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 2*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 4*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 4*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 8*(prev) in P1xP1 coords + tmp2.FromP1xP1(tmp1) // tmp2 = 8*(prev) in P2 coords + tmp1.Double(tmp2) // tmp1 = 16*(prev) in P1xP1 coords + v.fromP1xP1(tmp1) // v = 16*(prev) in P3 coords + table.SelectInto(multiple, digits[i]) + tmp1.Add(v, multiple) // tmp1 = x_i*Q + 16*(prev) in P1xP1 coords + } + v.fromP1xP1(tmp1) + return v +} + +// basepointNafTable is the nafLookupTable8 for the basepoint. +// It is precomputed the first time it's used. +func basepointNafTable() *nafLookupTable8 { + basepointNafTablePrecomp.initOnce.Do(func() { + basepointNafTablePrecomp.table.FromP3(NewGeneratorPoint()) + }) + return &basepointNafTablePrecomp.table +} + +var basepointNafTablePrecomp struct { + table nafLookupTable8 + initOnce sync.Once +} + +// VarTimeDoubleScalarBaseMult sets v = a * A + b * B, where B is the canonical +// generator, and returns v. +// +// Execution time depends on the inputs. +func (v *Point) VarTimeDoubleScalarBaseMult(a *Scalar, A *Point, b *Scalar) *Point { + checkInitialized(A) + + // Similarly to the single variable-base approach, we compute + // digits and use them with a lookup table. However, because + // we are allowed to do variable-time operations, we don't + // need constant-time lookups or constant-time digit + // computations. + // + // So we use a non-adjacent form of some width w instead of + // radix 16. This is like a binary representation (one digit + // for each binary place) but we allow the digits to grow in + // magnitude up to 2^{w-1} so that the nonzero digits are as + // sparse as possible. Intuitively, this "condenses" the + // "mass" of the scalar onto sparse coefficients (meaning + // fewer additions). + + basepointNafTable := basepointNafTable() + var aTable nafLookupTable5 + aTable.FromP3(A) + // Because the basepoint is fixed, we can use a wider NAF + // corresponding to a bigger table. + aNaf := a.nonAdjacentForm(5) + bNaf := b.nonAdjacentForm(8) + + // Find the first nonzero coefficient. + i := 255 + for j := i; j >= 0; j-- { + if aNaf[j] != 0 || bNaf[j] != 0 { + break + } + } + + multA := &projCached{} + multB := &affineCached{} + tmp1 := &projP1xP1{} + tmp2 := &projP2{} + tmp2.Zero() + + // Move from high to low bits, doubling the accumulator + // at each iteration and checking whether there is a nonzero + // coefficient to look up a multiple of. + for ; i >= 0; i-- { + tmp1.Double(tmp2) + + // Only update v if we have a nonzero coeff to add in. + if aNaf[i] > 0 { + v.fromP1xP1(tmp1) + aTable.SelectInto(multA, aNaf[i]) + tmp1.Add(v, multA) + } else if aNaf[i] < 0 { + v.fromP1xP1(tmp1) + aTable.SelectInto(multA, -aNaf[i]) + tmp1.Sub(v, multA) + } + + if bNaf[i] > 0 { + v.fromP1xP1(tmp1) + basepointNafTable.SelectInto(multB, bNaf[i]) + tmp1.AddAffine(v, multB) + } else if bNaf[i] < 0 { + v.fromP1xP1(tmp1) + basepointNafTable.SelectInto(multB, -bNaf[i]) + tmp1.SubAffine(v, multB) + } + + tmp2.FromP1xP1(tmp1) + } + + v.fromP2(tmp2) + return v +} diff --git a/vendor/filippo.io/edwards25519/tables.go b/vendor/filippo.io/edwards25519/tables.go new file mode 100644 index 0000000..83234bb --- /dev/null +++ b/vendor/filippo.io/edwards25519/tables.go @@ -0,0 +1,129 @@ +// Copyright (c) 2019 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 edwards25519 + +import ( + "crypto/subtle" +) + +// A dynamic lookup table for variable-base, constant-time scalar muls. +type projLookupTable struct { + points [8]projCached +} + +// A precomputed lookup table for fixed-base, constant-time scalar muls. +type affineLookupTable struct { + points [8]affineCached +} + +// A dynamic lookup table for variable-base, variable-time scalar muls. +type nafLookupTable5 struct { + points [8]projCached +} + +// A precomputed lookup table for fixed-base, variable-time scalar muls. +type nafLookupTable8 struct { + points [64]affineCached +} + +// Constructors. + +// Builds a lookup table at runtime. Fast. +func (v *projLookupTable) FromP3(q *Point) { + // Goal: v.points[i] = (i+1)*Q, i.e., Q, 2Q, ..., 8Q + // This allows lookup of -8Q, ..., -Q, 0, Q, ..., 8Q + v.points[0].FromP3(q) + tmpP3 := Point{} + tmpP1xP1 := projP1xP1{} + for i := 0; i < 7; i++ { + // Compute (i+1)*Q as Q + i*Q and convert to a projCached + // This is needlessly complicated because the API has explicit + // receivers instead of creating stack objects and relying on RVO + v.points[i+1].FromP3(tmpP3.fromP1xP1(tmpP1xP1.Add(q, &v.points[i]))) + } +} + +// This is not optimised for speed; fixed-base tables should be precomputed. +func (v *affineLookupTable) FromP3(q *Point) { + // Goal: v.points[i] = (i+1)*Q, i.e., Q, 2Q, ..., 8Q + // This allows lookup of -8Q, ..., -Q, 0, Q, ..., 8Q + v.points[0].FromP3(q) + tmpP3 := Point{} + tmpP1xP1 := projP1xP1{} + for i := 0; i < 7; i++ { + // Compute (i+1)*Q as Q + i*Q and convert to affineCached + v.points[i+1].FromP3(tmpP3.fromP1xP1(tmpP1xP1.AddAffine(q, &v.points[i]))) + } +} + +// Builds a lookup table at runtime. Fast. +func (v *nafLookupTable5) FromP3(q *Point) { + // Goal: v.points[i] = (2*i+1)*Q, i.e., Q, 3Q, 5Q, ..., 15Q + // This allows lookup of -15Q, ..., -3Q, -Q, 0, Q, 3Q, ..., 15Q + v.points[0].FromP3(q) + q2 := Point{} + q2.Add(q, q) + tmpP3 := Point{} + tmpP1xP1 := projP1xP1{} + for i := 0; i < 7; i++ { + v.points[i+1].FromP3(tmpP3.fromP1xP1(tmpP1xP1.Add(&q2, &v.points[i]))) + } +} + +// This is not optimised for speed; fixed-base tables should be precomputed. +func (v *nafLookupTable8) FromP3(q *Point) { + v.points[0].FromP3(q) + q2 := Point{} + q2.Add(q, q) + tmpP3 := Point{} + tmpP1xP1 := projP1xP1{} + for i := 0; i < 63; i++ { + v.points[i+1].FromP3(tmpP3.fromP1xP1(tmpP1xP1.AddAffine(&q2, &v.points[i]))) + } +} + +// Selectors. + +// Set dest to x*Q, where -8 <= x <= 8, in constant time. +func (v *projLookupTable) SelectInto(dest *projCached, x int8) { + // Compute xabs = |x| + xmask := x >> 7 + xabs := uint8((x + xmask) ^ xmask) + + dest.Zero() + for j := 1; j <= 8; j++ { + // Set dest = j*Q if |x| = j + cond := subtle.ConstantTimeByteEq(xabs, uint8(j)) + dest.Select(&v.points[j-1], dest, cond) + } + // Now dest = |x|*Q, conditionally negate to get x*Q + dest.CondNeg(int(xmask & 1)) +} + +// Set dest to x*Q, where -8 <= x <= 8, in constant time. +func (v *affineLookupTable) SelectInto(dest *affineCached, x int8) { + // Compute xabs = |x| + xmask := x >> 7 + xabs := uint8((x + xmask) ^ xmask) + + dest.Zero() + for j := 1; j <= 8; j++ { + // Set dest = j*Q if |x| = j + cond := subtle.ConstantTimeByteEq(xabs, uint8(j)) + dest.Select(&v.points[j-1], dest, cond) + } + // Now dest = |x|*Q, conditionally negate to get x*Q + dest.CondNeg(int(xmask & 1)) +} + +// Given odd x with 0 < x < 2^4, return x*Q (in variable time). +func (v *nafLookupTable5) SelectInto(dest *projCached, x int8) { + *dest = v.points[x/2] +} + +// Given odd x with 0 < x < 2^7, return x*Q (in variable time). +func (v *nafLookupTable8) SelectInto(dest *affineCached, x int8) { + *dest = v.points[x/2] +} |
