crypto: use go-ethereum secp256k1 package to avoid symbol conflict (#374)

1 files changed, 0 insertions, 325 deletions

diff --git a/crypto/secp256k1/curve.go b/crypto/secp256k1/curve.go
deleted file mode 100644
index 5409ee1d2..000000000
--- a/crypto/secp256k1/curve.go
+++ /dev/null
@@ -1,325 +0,0 @@
-// Copyright 2010 The Go Authors. All rights reserved.
-// Copyright 2011 ThePiachu. All rights reserved.
-// Copyright 2015 Jeffrey Wilcke, Felix Lange, Gustav Simonsson. 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.
-// * The name of ThePiachu may not 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.
-
-package secp256k1
-
-import (
-	"crypto/elliptic"
-	"math/big"
-	"unsafe"
-)
-
-/*
-#include "libsecp256k1/include/secp256k1.h"
-extern int secp256k1_ext_scalar_mul(const secp256k1_context* ctx, const unsigned char *point, const unsigned char *scalar);
-*/
-import "C"
-
-const (
-	// number of bits in a big.Word
-	wordBits = 32 << (uint64(^big.Word(0)) >> 63)
-	// number of bytes in a big.Word
-	wordBytes = wordBits / 8
-)
-
-// readBits encodes the absolute value of bigint as big-endian bytes. Callers
-// must ensure that buf has enough space. If buf is too short the result will
-// be incomplete.
-func readBits(bigint *big.Int, buf []byte) {
-	i := len(buf)
-	for _, d := range bigint.Bits() {
-		for j := 0; j < wordBytes && i > 0; j++ {
-			i--
-			buf[i] = byte(d)
-			d >>= 8
-		}
-	}
-}
-
-// This code is from https://github.com/ThePiachu/GoBit and implements
-// several Koblitz elliptic curves over prime fields.
-//
-// The curve methods, internally, on Jacobian coordinates. For a given
-// (x, y) position on the curve, the Jacobian coordinates are (x1, y1,
-// z1) where x = x1/z1² and y = y1/z1³. The greatest speedups come
-// when the whole calculation can be performed within the transform
-// (as in ScalarMult and ScalarBaseMult). But even for Add and Double,
-// it's faster to apply and reverse the transform than to operate in
-// affine coordinates.
-
-// A BitCurve represents a Koblitz Curve with a=0.
-// See http://www.hyperelliptic.org/EFD/g1p/auto-shortw.html
-type BitCurve struct {
-	P       *big.Int // the order of the underlying field
-	N       *big.Int // the order of the base point
-	B       *big.Int // the constant of the BitCurve equation
-	Gx, Gy  *big.Int // (x,y) of the base point
-	BitSize int      // the size of the underlying field
-}
-
-func (BitCurve *BitCurve) Params() *elliptic.CurveParams {
-	return &elliptic.CurveParams{
-		P:       BitCurve.P,
-		N:       BitCurve.N,
-		B:       BitCurve.B,
-		Gx:      BitCurve.Gx,
-		Gy:      BitCurve.Gy,
-		BitSize: BitCurve.BitSize,
-	}
-}
-
-// IsOnCurve returns true if the given (x,y) lies on the BitCurve.
-func (BitCurve *BitCurve) IsOnCurve(x, y *big.Int) bool {
-	// y² = x³ + b
-	y2 := new(big.Int).Mul(y, y) //y²
-	y2.Mod(y2, BitCurve.P)       //y²%P
-
-	x3 := new(big.Int).Mul(x, x) //x²
-	x3.Mul(x3, x)                //x³
-
-	x3.Add(x3, BitCurve.B) //x³+B
-	x3.Mod(x3, BitCurve.P) //(x³+B)%P
-
-	return x3.Cmp(y2) == 0
-}
-
-//TODO: double check if the function is okay
-// affineFromJacobian reverses the Jacobian transform. See the comment at the
-// top of the file.
-func (BitCurve *BitCurve) affineFromJacobian(x, y, z *big.Int) (xOut, yOut *big.Int) {
-	zinv := new(big.Int).ModInverse(z, BitCurve.P)
-	zinvsq := new(big.Int).Mul(zinv, zinv)
-
-	xOut = new(big.Int).Mul(x, zinvsq)
-	xOut.Mod(xOut, BitCurve.P)
-	zinvsq.Mul(zinvsq, zinv)
-	yOut = new(big.Int).Mul(y, zinvsq)
-	yOut.Mod(yOut, BitCurve.P)
-	return
-}
-
-// Add returns the sum of (x1,y1) and (x2,y2)
-func (BitCurve *BitCurve) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int) {
-	z := new(big.Int).SetInt64(1)
-	return BitCurve.affineFromJacobian(BitCurve.addJacobian(x1, y1, z, x2, y2, z))
-}
-
-// addJacobian takes two points in Jacobian coordinates, (x1, y1, z1) and
-// (x2, y2, z2) and returns their sum, also in Jacobian form.
-func (BitCurve *BitCurve) addJacobian(x1, y1, z1, x2, y2, z2 *big.Int) (*big.Int, *big.Int, *big.Int) {
-	// See http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#addition-add-2007-bl
-	z1z1 := new(big.Int).Mul(z1, z1)
-	z1z1.Mod(z1z1, BitCurve.P)
-	z2z2 := new(big.Int).Mul(z2, z2)
-	z2z2.Mod(z2z2, BitCurve.P)
-
-	u1 := new(big.Int).Mul(x1, z2z2)
-	u1.Mod(u1, BitCurve.P)
-	u2 := new(big.Int).Mul(x2, z1z1)
-	u2.Mod(u2, BitCurve.P)
-	h := new(big.Int).Sub(u2, u1)
-	if h.Sign() == -1 {
-		h.Add(h, BitCurve.P)
-	}
-	i := new(big.Int).Lsh(h, 1)
-	i.Mul(i, i)
-	j := new(big.Int).Mul(h, i)
-
-	s1 := new(big.Int).Mul(y1, z2)
-	s1.Mul(s1, z2z2)
-	s1.Mod(s1, BitCurve.P)
-	s2 := new(big.Int).Mul(y2, z1)
-	s2.Mul(s2, z1z1)
-	s2.Mod(s2, BitCurve.P)
-	r := new(big.Int).Sub(s2, s1)
-	if r.Sign() == -1 {
-		r.Add(r, BitCurve.P)
-	}
-	r.Lsh(r, 1)
-	v := new(big.Int).Mul(u1, i)
-
-	x3 := new(big.Int).Set(r)
-	x3.Mul(x3, x3)
-	x3.Sub(x3, j)
-	x3.Sub(x3, v)
-	x3.Sub(x3, v)
-	x3.Mod(x3, BitCurve.P)
-
-	y3 := new(big.Int).Set(r)
-	v.Sub(v, x3)
-	y3.Mul(y3, v)
-	s1.Mul(s1, j)
-	s1.Lsh(s1, 1)
-	y3.Sub(y3, s1)
-	y3.Mod(y3, BitCurve.P)
-
-	z3 := new(big.Int).Add(z1, z2)
-	z3.Mul(z3, z3)
-	z3.Sub(z3, z1z1)
-	if z3.Sign() == -1 {
-		z3.Add(z3, BitCurve.P)
-	}
-	z3.Sub(z3, z2z2)
-	if z3.Sign() == -1 {
-		z3.Add(z3, BitCurve.P)
-	}
-	z3.Mul(z3, h)
-	z3.Mod(z3, BitCurve.P)
-
-	return x3, y3, z3
-}
-
-// Double returns 2*(x,y)
-func (BitCurve *BitCurve) Double(x1, y1 *big.Int) (*big.Int, *big.Int) {
-	z1 := new(big.Int).SetInt64(1)
-	return BitCurve.affineFromJacobian(BitCurve.doubleJacobian(x1, y1, z1))
-}
-
-// doubleJacobian takes a point in Jacobian coordinates, (x, y, z), and
-// returns its double, also in Jacobian form.
-func (BitCurve *BitCurve) doubleJacobian(x, y, z *big.Int) (*big.Int, *big.Int, *big.Int) {
-	// See http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#doubling-dbl-2009-l
-
-	a := new(big.Int).Mul(x, x) //X1²
-	b := new(big.Int).Mul(y, y) //Y1²
-	c := new(big.Int).Mul(b, b) //B²
-
-	d := new(big.Int).Add(x, b) //X1+B
-	d.Mul(d, d)                 //(X1+B)²
-	d.Sub(d, a)                 //(X1+B)²-A
-	d.Sub(d, c)                 //(X1+B)²-A-C
-	d.Mul(d, big.NewInt(2))     //2*((X1+B)²-A-C)
-
-	e := new(big.Int).Mul(big.NewInt(3), a) //3*A
-	f := new(big.Int).Mul(e, e)             //E²
-
-	x3 := new(big.Int).Mul(big.NewInt(2), d) //2*D
-	x3.Sub(f, x3)                            //F-2*D
-	x3.Mod(x3, BitCurve.P)
-
-	y3 := new(big.Int).Sub(d, x3)                  //D-X3
-	y3.Mul(e, y3)                                  //E*(D-X3)
-	y3.Sub(y3, new(big.Int).Mul(big.NewInt(8), c)) //E*(D-X3)-8*C
-	y3.Mod(y3, BitCurve.P)
-
-	z3 := new(big.Int).Mul(y, z) //Y1*Z1
-	z3.Mul(big.NewInt(2), z3)    //3*Y1*Z1
-	z3.Mod(z3, BitCurve.P)
-
-	return x3, y3, z3
-}
-
-func (BitCurve *BitCurve) ScalarMult(Bx, By *big.Int, scalar []byte) (*big.Int, *big.Int) {
-	// Ensure scalar is exactly 32 bytes. We pad always, even if
-	// scalar is 32 bytes long, to avoid a timing side channel.
-	if len(scalar) > 32 {
-		panic("can't handle scalars > 256 bits")
-	}
-	// NOTE: potential timing issue
-	padded := make([]byte, 32)
-	copy(padded[32-len(scalar):], scalar)
-	scalar = padded
-
-	// Do the multiplication in C, updating point.
-	point := make([]byte, 64)
-	readBits(Bx, point[:32])
-	readBits(By, point[32:])
-
-	pointPtr := (*C.uchar)(unsafe.Pointer(&point[0]))
-	scalarPtr := (*C.uchar)(unsafe.Pointer(&scalar[0]))
-	res := C.secp256k1_ext_scalar_mul(context, pointPtr, scalarPtr)
-
-	// Unpack the result and clear temporaries.
-	x := new(big.Int).SetBytes(point[:32])
-	y := new(big.Int).SetBytes(point[32:])
-	for i := range point {
-		point[i] = 0
-	}
-	for i := range padded {
-		scalar[i] = 0
-	}
-	if res != 1 {
-		return nil, nil
-	}
-	return x, y
-}
-
-// ScalarBaseMult returns k*G, where G is the base point of the group and k is
-// an integer in big-endian form.
-func (BitCurve *BitCurve) ScalarBaseMult(k []byte) (*big.Int, *big.Int) {
-	return BitCurve.ScalarMult(BitCurve.Gx, BitCurve.Gy, k)
-}
-
-// Marshal converts a point into the form specified in section 4.3.6 of ANSI
-// X9.62.
-func (BitCurve *BitCurve) Marshal(x, y *big.Int) []byte {
-	byteLen := (BitCurve.BitSize + 7) >> 3
-	ret := make([]byte, 1+2*byteLen)
-	ret[0] = 4 // uncompressed point flag
-	readBits(x, ret[1:1+byteLen])
-	readBits(y, ret[1+byteLen:])
-	return ret
-}
-
-// Unmarshal converts a point, serialised by Marshal, into an x, y pair. On
-// error, x = nil.
-func (BitCurve *BitCurve) Unmarshal(data []byte) (x, y *big.Int) {
-	byteLen := (BitCurve.BitSize + 7) >> 3
-	if len(data) != 1+2*byteLen {
-		return
-	}
-	if data[0] != 4 { // uncompressed form
-		return
-	}
-	x = new(big.Int).SetBytes(data[1 : 1+byteLen])
-	y = new(big.Int).SetBytes(data[1+byteLen:])
-	return
-}
-
-var theCurve = new(BitCurve)
-
-func init() {
-	// See SEC 2 section 2.7.1
-	// curve parameters taken from:
-	// http://www.secg.org/sec2-v2.pdf
-	theCurve.P, _ = new(big.Int).SetString("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F", 0)
-	theCurve.N, _ = new(big.Int).SetString("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141", 0)
-	theCurve.B, _ = new(big.Int).SetString("0x0000000000000000000000000000000000000000000000000000000000000007", 0)
-	theCurve.Gx, _ = new(big.Int).SetString("0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798", 0)
-	theCurve.Gy, _ = new(big.Int).SetString("0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8", 0)
-	theCurve.BitSize = 256
-}
-
-// S256 returns a BitCurve which implements secp256k1.
-func S256() *BitCurve {
-	return theCurve
-}