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kdf: move Kdf() from sm3 to kdf

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Sun Yimin 2022-08-25 11:48:41 +08:00 committed by GitHub
parent 8f5dcb842e
commit eedd5ebc2b
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GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 142 additions and 65 deletions
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9
internal/subtle/constant_time.go Normal file
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@ -0,0 +1,9 @@
package subtle
func ConstantTimeAllZero(bytes []byte) bool {
var b uint8
for _, v := range bytes {
b |= v
}
return b == 0
}

24
internal/subtle/constant_time_test.go Normal file
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@ -0,0 +1,24 @@
package subtle
import "testing"
func TestConstantTimeAllZero(t *testing.T) {
type args struct {
bytes []byte
}
tests := []struct {
name string
args args
want bool
}{
{"all zero", args{[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, true},
{"not all zero", args{[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 1}}, false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := ConstantTimeAllZero(tt.args.bytes); got != tt.want {
t.Errorf("ConstantTimeAllZero() = %v, want %v", got, tt.want)
}
})
}
}

27
kdf/kdf.go Normal file
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@ -0,0 +1,27 @@
package kdf
import (
"encoding/binary"
"hash"
)
// Kdf key derivation function, compliance with GB/T 32918.4-2016 5.4.3.
// ANSI-X9.63-KDF
func Kdf(md hash.Hash, z []byte, len int) []byte {
limit := uint64(len+md.Size()-1) / uint64(md.Size())
if limit >= uint64(1<<32)-1 {
panic("kdf: key length too long")
}
var countBytes [4]byte
var ct uint32 = 1
k := make([]byte, len+md.Size()-1)
for i := 0; i < int(limit); i++ {
binary.BigEndian.PutUint32(countBytes[:], ct)
md.Write(z)
md.Write(countBytes[:])
copy(k[i*md.Size():], md.Sum(nil))
ct++
md.Reset()
}
return k[:len]
}

64
kdf/kdf_test.go Normal file
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@ -0,0 +1,64 @@
package kdf
import (
"encoding/hex"
"hash"
"math/big"
"reflect"
"testing"
"github.com/emmansun/gmsm/sm3"
)
func TestKdf(t *testing.T) {
type args struct {
md hash.Hash
z []byte
len int
}
tests := []struct {
name string
args args
want []byte
}{
{"sm3 case 1", args{sm3.New(), []byte("emmansun"), 16}, []byte{112, 137, 147, 239, 19, 136, 160, 174, 66, 69, 161, 155, 182, 192, 37, 84}},
{"sm3 case 2", args{sm3.New(), []byte("emmansun"), 32}, []byte{112, 137, 147, 239, 19, 136, 160, 174, 66, 69, 161, 155, 182, 192, 37, 84, 198, 50, 99, 62, 53, 109, 219, 152, 155, 235, 128, 79, 218, 150, 207, 212}},
{"sm3 case 3", args{sm3.New(), []byte("emmansun"), 48}, []byte{112, 137, 147, 239, 19, 136, 160, 174, 66, 69, 161, 155, 182, 192, 37, 84, 198, 50, 99, 62, 53, 109, 219, 152, 155, 235, 128, 79, 218, 150, 207, 212, 126, 186, 79, 164, 96, 231, 178, 119, 188, 107, 76, 228, 208, 126, 212, 147}},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := Kdf(tt.args.md, tt.args.z, tt.args.len); !reflect.DeepEqual(got, tt.want) {
t.Errorf("Kdf() = %v, want %v", got, tt.want)
}
})
}
}
func TestKdfOldCase(t *testing.T) {
x2, _ := new(big.Int).SetString("64D20D27D0632957F8028C1E024F6B02EDF23102A566C932AE8BD613A8E865FE", 16)
y2, _ := new(big.Int).SetString("58D225ECA784AE300A81A2D48281A828E1CEDF11C4219099840265375077BF78", 16)
expected := "006e30dae231b071dfad8aa379e90264491603"
result := Kdf(sm3.New(), append(x2.Bytes(), y2.Bytes()...), 19)
resultStr := hex.EncodeToString(result)
if expected != resultStr {
t.Fatalf("expected %s, real value %s", expected, resultStr)
}
}
func shouldPanic(t *testing.T, f func()) {
t.Helper()
defer func() { _ = recover() }()
f()
t.Errorf("should have panicked")
}
// This case should be failed on 32bits system.
func TestKdfPanic(t *testing.T) {
shouldPanic(t, func() {
Kdf(sm3.New(), []byte("123456"), 1<<37)
})
}

7
sm2/sm2.go
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@ -24,6 +24,7 @@ import (
"github.com/emmansun/gmsm/internal/randutil"
"github.com/emmansun/gmsm/internal/subtle"
"github.com/emmansun/gmsm/kdf"
"github.com/emmansun/gmsm/sm2/sm2ec"
"github.com/emmansun/gmsm/sm3"
"golang.org/x/crypto/cryptobyte"
@ -335,7 +336,8 @@ func Encrypt(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *Encrypter
//A5, calculate t=KDF(x2||y2, klen)
var kdfCount int = 0
c2, success := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
c2 := kdf.Kdf(sm3.New(), append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
success := subtle.ConstantTimeAllZero(c2)
if !success {
kdfCount++
if kdfCount > maxRetryLimit {
@ -396,7 +398,8 @@ 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)
msg, success := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
msg := kdf.Kdf(sm3.New(), append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
success := subtle.ConstantTimeAllZero(c2)
if !success {
return nil, errors.New("sm2: invalid cipher text")
}

7
sm2/sm2_keyexchange.go
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@ -7,6 +7,7 @@ import (
"io"
"math/big"
"github.com/emmansun/gmsm/kdf"
"github.com/emmansun/gmsm/sm3"
)
@ -184,11 +185,7 @@ func (ke *KeyExchange) generateSharedKey(isResponder bool) ([]byte, error) {
buffer = append(buffer, ke.z...)
buffer = append(buffer, ke.peerZ...)
}
key, ok := sm3.Kdf(buffer, ke.keyLength)
if !ok {
return nil, errors.New("sm2: internal error, kdf failed")
}
return key, nil
return kdf.Kdf(sm3.New(), buffer, ke.keyLength), nil
}
// avf is the associative value function.

23
sm3/sm3.go
View File

@ -209,26 +209,3 @@ 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()
}
k = k[:len]
var b uint8
for _, v := range k {
b |= v
}
return k, int((uint32(b)-1)>>31) != 1
}

20
sm3/sm3_test.go
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@ -5,11 +5,9 @@ import (
"crypto/sha256"
"encoding"
"encoding/base64"
"encoding/hex"
"fmt"
"hash"
"io"
"math/big"
"testing"
"golang.org/x/sys/cpu"
@ -115,24 +113,6 @@ 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)

13
sm9/sm9.go
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@ -11,6 +11,7 @@ import (
"math/big"
"github.com/emmansun/gmsm/internal/subtle"
"github.com/emmansun/gmsm/kdf"
"github.com/emmansun/gmsm/sm3"
"github.com/emmansun/gmsm/sm9/bn256"
"golang.org/x/crypto/cryptobyte"
@ -226,7 +227,8 @@ func WrapKey(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte,
buffer = append(buffer, w.Marshal()...)
buffer = append(buffer, uid...)
key, ok = sm3.Kdf(buffer, kLen)
key = kdf.Kdf(sm3.New(), buffer, kLen)
ok = subtle.ConstantTimeAllZero(key)
if ok {
break
}
@ -297,7 +299,8 @@ func UnwrapKey(priv *EncryptPrivateKey, uid []byte, cipher *bn256.G1, kLen int)
buffer = append(buffer, w.Marshal()...)
buffer = append(buffer, uid...)
key, ok := sm3.Kdf(buffer, kLen)
key := kdf.Kdf(sm3.New(), buffer, kLen)
ok := subtle.ConstantTimeAllZero(key)
if !ok {
return nil, errors.New("sm9: invalid cipher")
}
@ -562,11 +565,7 @@ func (ke *KeyExchange) generateSharedKey(isResponder bool) ([]byte, error) {
buffer = append(buffer, ke.g2.Marshal()...)
buffer = append(buffer, ke.g3.Marshal()...)
key, ok := sm3.Kdf(buffer, ke.keyLength)
if !ok {
return nil, errors.New("sm9: internal error, kdf failed")
}
return key, nil
return kdf.Kdf(sm3.New(), buffer, ke.keyLength), nil
}
func respondKeyExchange(ke *KeyExchange, hid byte, r *big.Int, rA *bn256.G1) (*bn256.G1, []byte, error) {

13
sm9/sm9_test.go
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@ -7,6 +7,7 @@ import (
"testing"
"github.com/emmansun/gmsm/internal/subtle"
"github.com/emmansun/gmsm/kdf"
"github.com/emmansun/gmsm/sm3"
"github.com/emmansun/gmsm/sm9/bn256"
)
@ -437,10 +438,8 @@ func TestWrapKeySM9Sample(t *testing.T) {
buffer = append(buffer, w.Marshal()...)
buffer = append(buffer, uid...)
key, ok := sm3.Kdf(buffer, 32)
if !ok {
t.Failed()
}
key := kdf.Kdf(sm3.New(), buffer, 32)
if hex.EncodeToString(key) != expectedKey {
t.Errorf("expected %v, got %v\n", expectedKey, hex.EncodeToString(key))
}
@ -501,10 +500,8 @@ func TestEncryptSM9Sample(t *testing.T) {
buffer = append(buffer, w.Marshal()...)
buffer = append(buffer, uid...)
key, ok := sm3.Kdf(buffer, len(plaintext)+32)
if !ok {
t.Failed()
}
key := kdf.Kdf(sm3.New(), buffer, len(plaintext)+32)
if hex.EncodeToString(key) != expectedKey {
t.Errorf("not expected key")
}