From 5f7826270c9e87509fd7731ec64953a5e4761de0 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Tue, 28 Feb 2017 15:09:11 +0100 Subject: all: unify big.Int zero checks, use common/math in more places (#3716) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * common/math: optimize PaddedBigBytes, use it more name old time/op new time/op delta PaddedBigBytes-8 71.1ns ± 5% 46.1ns ± 1% -35.15% (p=0.000 n=20+19) name old alloc/op new alloc/op delta PaddedBigBytes-8 48.0B ± 0% 32.0B ± 0% -33.33% (p=0.000 n=20+20) * all: unify big.Int zero checks Various checks were in use. This commit replaces them all with Int.Sign, which is cheaper and less code. eg templates: func before(x *big.Int) bool { return x.BitLen() == 0 } func after(x *big.Int) bool { return x.Sign() == 0 } func before(x *big.Int) bool { return x.BitLen() > 0 } func after(x *big.Int) bool { return x.Sign() != 0 } func before(x *big.Int) int { return x.Cmp(common.Big0) } func after(x *big.Int) int { return x.Sign() } * common/math, crypto/secp256k1: make ReadBits public in package math --- crypto/secp256k1/curve.go | 6 ++++-- crypto/secp256k1/curve_test.go | 39 --------------------------------------- crypto/secp256k1/secp256.go | 14 -------------- crypto/secp256k1/secp256_test.go | 5 ++--- crypto/signature_cgo.go | 4 ++-- 5 files changed, 8 insertions(+), 60 deletions(-) delete mode 100644 crypto/secp256k1/curve_test.go (limited to 'crypto') diff --git a/crypto/secp256k1/curve.go b/crypto/secp256k1/curve.go index 61cad5463..ec6d266ce 100644 --- a/crypto/secp256k1/curve.go +++ b/crypto/secp256k1/curve.go @@ -36,6 +36,8 @@ import ( "math/big" "sync" "unsafe" + + "github.com/ethereum/go-ethereum/common/math" ) /* @@ -230,8 +232,8 @@ func (BitCurve *BitCurve) ScalarMult(Bx, By *big.Int, scalar []byte) (*big.Int, // Do the multiplication in C, updating point. point := make([]byte, 64) - readBits(point[:32], Bx) - readBits(point[32:], By) + math.ReadBits(Bx, point[:32]) + math.ReadBits(By, point[32:]) pointPtr := (*C.uchar)(unsafe.Pointer(&point[0])) scalarPtr := (*C.uchar)(unsafe.Pointer(&scalar[0])) res := C.secp256k1_pubkey_scalar_mul(context, pointPtr, scalarPtr) diff --git a/crypto/secp256k1/curve_test.go b/crypto/secp256k1/curve_test.go deleted file mode 100644 index d915ee852..000000000 --- a/crypto/secp256k1/curve_test.go +++ /dev/null @@ -1,39 +0,0 @@ -// Copyright 2015 The go-ethereum Authors -// This file is part of the go-ethereum library. -// -// The go-ethereum library is free software: you can redistribute it and/or modify -// it under the terms of the GNU Lesser General Public License as published by -// the Free Software Foundation, either version 3 of the License, or -// (at your option) any later version. -// -// The go-ethereum library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU Lesser General Public License for more details. -// -// You should have received a copy of the GNU Lesser General Public License -// along with the go-ethereum library. If not, see . - -package secp256k1 - -import ( - "bytes" - "encoding/hex" - "math/big" - "testing" -) - -func TestReadBits(t *testing.T) { - check := func(input string) { - want, _ := hex.DecodeString(input) - int, _ := new(big.Int).SetString(input, 16) - buf := make([]byte, len(want)) - readBits(buf, int) - if !bytes.Equal(buf, want) { - t.Errorf("have: %x\nwant: %x", buf, want) - } - } - check("000000000000000000000000000000000000000000000000000000FEFCF3F8F0") - check("0000000000012345000000000000000000000000000000000000FEFCF3F8F0") - check("18F8F8F1000111000110011100222004330052300000000000000000FEFCF3F8F0") -} diff --git a/crypto/secp256k1/secp256.go b/crypto/secp256k1/secp256.go index 1a152a670..0ffa04fe0 100644 --- a/crypto/secp256k1/secp256.go +++ b/crypto/secp256k1/secp256.go @@ -38,7 +38,6 @@ import "C" import ( "errors" - "math/big" "unsafe" ) @@ -129,16 +128,3 @@ func checkSignature(sig []byte) error { } return nil } - -// reads num into buf as big-endian bytes. -func readBits(buf []byte, num *big.Int) { - const wordLen = int(unsafe.Sizeof(big.Word(0))) - i := len(buf) - for _, d := range num.Bits() { - for j := 0; j < wordLen && i > 0; j++ { - i-- - buf[i] = byte(d) - d >>= 8 - } - } -} diff --git a/crypto/secp256k1/secp256_test.go b/crypto/secp256k1/secp256_test.go index 287ab512e..f6582ecd5 100644 --- a/crypto/secp256k1/secp256_test.go +++ b/crypto/secp256k1/secp256_test.go @@ -24,6 +24,7 @@ import ( "encoding/hex" "testing" + "github.com/ethereum/go-ethereum/common/math" "github.com/ethereum/go-ethereum/crypto/randentropy" ) @@ -35,9 +36,7 @@ func generateKeyPair() (pubkey, privkey []byte) { panic(err) } pubkey = elliptic.Marshal(S256(), key.X, key.Y) - privkey = make([]byte, 32) - readBits(privkey, key.D) - return pubkey, privkey + return pubkey, math.PaddedBigBytes(key.D, 32) } func randSig() []byte { diff --git a/crypto/signature_cgo.go b/crypto/signature_cgo.go index 5faa6061f..d1485de08 100644 --- a/crypto/signature_cgo.go +++ b/crypto/signature_cgo.go @@ -23,7 +23,7 @@ import ( "crypto/elliptic" "fmt" - "github.com/ethereum/go-ethereum/common" + "github.com/ethereum/go-ethereum/common/math" "github.com/ethereum/go-ethereum/crypto/secp256k1" ) @@ -53,7 +53,7 @@ func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) { if len(hash) != 32 { return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash)) } - seckey := common.LeftPadBytes(prv.D.Bytes(), prv.Params().BitSize/8) + seckey := math.PaddedBigBytes(prv.D, prv.Params().BitSize/8) defer zeroBytes(seckey) return secp256k1.Sign(hash, seckey) } -- cgit