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extract kdf to sm3

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Sun Yimin 2022-06-10 10:29:12 +08:00 committed by GitHub
parent 6b8782ddf1
commit ef51a679a7
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 49 additions and 54 deletions
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40
sm2/sm2.go
View File

@ -16,7 +16,6 @@ import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/sha512"
"encoding/binary"
"errors"
"fmt"
"io"
@ -25,6 +24,7 @@ import (
"sync"
"github.com/emmansun/gmsm/internal/randutil"
"github.com/emmansun/gmsm/internal/xor"
"github.com/emmansun/gmsm/sm3"
"golang.org/x/crypto/cryptobyte"
"golang.org/x/crypto/cryptobyte/asn1"
@ -287,29 +287,6 @@ func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error)
const maxRetryLimit = 100
// kdf key derivation function, compliance with GB/T 32918.4-2016 5.4.3.
func kdf(z []byte, len int) ([]byte, bool) {
limit := (len + sm3.Size - 1) >> sm3.SizeBitSize
md := sm3.New()
var countBytes [4]byte
var ct uint32 = 1
k := make([]byte, len+sm3.Size-1)
for i := 0; i < limit; i++ {
binary.BigEndian.PutUint32(countBytes[:], ct)
md.Write(z)
md.Write(countBytes[:])
copy(k[i*sm3.Size:], md.Sum(nil))
ct++
md.Reset()
}
for i := 0; i < len; i++ {
if k[i] != 0 {
return k[:len], true
}
}
return k, false
}
func calculateC3(curve elliptic.Curve, x2, y2 *big.Int, msg []byte) []byte {
md := sm3.New()
md.Write(toBytes(curve, x2))
@ -364,7 +341,7 @@ func Encrypt(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *Encrypter
//A5, calculate t=KDF(x2||y2, klen)
var kdfCount int = 0
t, success := kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
c2, success := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
if !success {
kdfCount++
if kdfCount > maxRetryLimit {
@ -374,10 +351,7 @@ func Encrypt(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *Encrypter
}
//A6, C2 = M + t;
c2 := make([]byte, msgLen)
for i := 0; i < msgLen; i++ {
c2[i] = msg[i] ^ t[i]
}
xor.XorBytes(c2, msg, c2)
//A7, C3 = hash(x2||M||y2)
c3 := calculateC3(curve, x2, y2, msg)
@ -428,16 +402,14 @@ func rawDecrypt(priv *PrivateKey, x1, y1 *big.Int, c2, c3 []byte) ([]byte, error
curve := priv.Curve
x2, y2 := curve.ScalarMult(x1, y1, priv.D.Bytes())
msgLen := len(c2)
t, success := kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
msg, success := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
if !success {
return nil, errors.New("sm2: invalid cipher text")
}
//B5, calculate msg = c2 ^ t
msg := make([]byte, msgLen)
for i := 0; i < msgLen; i++ {
msg[i] = c2[i] ^ t[i]
}
xor.XorBytes(msg, c2, msg)
u := calculateC3(curve, x2, y2, msg)
for i := 0; i < sm3.Size; i++ {
if c3[i] != u[i] {

20
sm2/sm2_test.go
View File

@ -5,32 +5,12 @@ import (
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"encoding/hex"
"math/big"
"reflect"
"testing"
"github.com/emmansun/gmsm/sm3"
)
func Test_kdf(t *testing.T) {
x2, _ := new(big.Int).SetString("64D20D27D0632957F8028C1E024F6B02EDF23102A566C932AE8BD613A8E865FE", 16)
y2, _ := new(big.Int).SetString("58D225ECA784AE300A81A2D48281A828E1CEDF11C4219099840265375077BF78", 16)
expected := "006e30dae231b071dfad8aa379e90264491603"
result, success := kdf(append(x2.Bytes(), y2.Bytes()...), 19)
if !success {
t.Fatalf("failed")
}
resultStr := hex.EncodeToString(result)
if expected != resultStr {
t.Fatalf("expected %s, real value %s", expected, resultStr)
}
}
func Test_SplicingOrder(t *testing.T) {
priv, _ := GenerateKey(rand.Reader)
tests := []struct {

23
sm3/sm3.go
View File

@ -209,3 +209,26 @@ func Sum(data []byte) [Size]byte {
d.Write(data)
return d.checkSum()
}
// Kdf key derivation function, compliance with GB/T 32918.4-2016 5.4.3.
func Kdf(z []byte, len int) ([]byte, bool) {
limit := (len + Size - 1) >> SizeBitSize
md := New()
var countBytes [4]byte
var ct uint32 = 1
k := make([]byte, len+Size-1)
for i := 0; i < limit; i++ {
binary.BigEndian.PutUint32(countBytes[:], ct)
md.Write(z)
md.Write(countBytes[:])
copy(k[i*Size:], md.Sum(nil))
ct++
md.Reset()
}
for i := 0; i < len; i++ {
if k[i] != 0 {
return k[:len], true
}
}
return k, false
}

20
sm3/sm3_test.go
View File

@ -5,9 +5,11 @@ import (
"crypto/sha256"
"encoding"
"encoding/base64"
"encoding/hex"
"fmt"
"hash"
"io"
"math/big"
"testing"
"golang.org/x/sys/cpu"
@ -113,6 +115,24 @@ func TestBlockSize(t *testing.T) {
fmt.Printf("ARM64 has sm3 %v, has sm4 %v, has aes %v\n", cpu.ARM64.HasSM3, cpu.ARM64.HasSM4, cpu.ARM64.HasAES)
}
func Test_kdf(t *testing.T) {
x2, _ := new(big.Int).SetString("64D20D27D0632957F8028C1E024F6B02EDF23102A566C932AE8BD613A8E865FE", 16)
y2, _ := new(big.Int).SetString("58D225ECA784AE300A81A2D48281A828E1CEDF11C4219099840265375077BF78", 16)
expected := "006e30dae231b071dfad8aa379e90264491603"
result, success := Kdf(append(x2.Bytes(), y2.Bytes()...), 19)
if !success {
t.Fatalf("failed")
}
resultStr := hex.EncodeToString(result)
if expected != resultStr {
t.Fatalf("expected %s, real value %s", expected, resultStr)
}
}
var bench = New()
var benchSH256 = sha256.New()
var buf = make([]byte, 8192)