kdf: share Z hash state #220

cfca/pkcs12_sm2.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"math/big"
 
-	"github.com/emmansun/gmsm/kdf"
 	"github.com/emmansun/gmsm/padding"
 	"github.com/emmansun/gmsm/pkcs"
 	"github.com/emmansun/gmsm/sm2"
@@ -59,7 +58,7 @@ func ParseSM2(password, data []byte) (*sm2.PrivateKey, *smx509.Certificate, erro
 	if !keys.EncryptedKey.Algorithm.Equal(oidSM4) && !keys.EncryptedKey.Algorithm.Equal(oidSM4CBC) {
 		return nil, nil, fmt.Errorf("cfca: unsupported algorithm <%v>", keys.EncryptedKey.Algorithm)
 	}
-	ivkey := kdf.Kdf(sm3.New(), password, 32)
+	ivkey := sm3.Kdf(password, 32)
 	marshalledIV, err := asn1.Marshal(ivkey[:16])
 	if err != nil {
 		return nil, nil, err
@@ -91,7 +90,7 @@ func MarshalSM2(password []byte, key *sm2.PrivateKey, cert *smx509.Certificate)
 	if len(password) == 0 {
 		return nil, errors.New("cfca: invalid password")
 	}
-	ivkey := kdf.Kdf(sm3.New(), password, 32)
+	ivkey := sm3.Kdf(password, 32)
 	block, err := sm4.NewCipher(ivkey[16:])
 	if err != nil {
 		return nil, err

kdf/kdf.go

@@ -2,27 +2,48 @@
 package kdf
 
 import (
+	"encoding"
 	"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 {
+func Kdf(newHash func() hash.Hash, z []byte, keyLen int) []byte {
-	limit := uint64(len+md.Size()-1) / uint64(md.Size())
+	baseMD := newHash()
+	limit := uint64(keyLen+baseMD.Size()-1) / uint64(baseMD.Size())
 	if limit >= uint64(1<<32)-1 {
 		panic("kdf: key length too long")
 	}
 	var countBytes [4]byte
 	var ct uint32 = 1
 	var k []byte
+
+	marshaler, ok := baseMD.(encoding.BinaryMarshaler)
+	if limit == 1 || len(z) < baseMD.BlockSize() || !ok {
 		for i := 0; i < int(limit); i++ {
 			binary.BigEndian.PutUint32(countBytes[:], ct)
-		md.Write(z)
+			baseMD.Write(z)
+			baseMD.Write(countBytes[:])
+			k = baseMD.Sum(k)
+			ct++
+			baseMD.Reset()
+		}
+	} else {
+		baseMD.Write(z)
+		zstate, _ := marshaler.MarshalBinary()
+		for i := 0; i < int(limit); i++ {
+			md := newHash()
+			err := md.(encoding.BinaryUnmarshaler).UnmarshalBinary(zstate)
+			if err != nil {
+				panic(err)
+			}
+			binary.BigEndian.PutUint32(countBytes[:], ct)
 			md.Write(countBytes[:])
 			k = md.Sum(k)
 			ct++
-		md.Reset()
 		}		
-	return k[:len]
+	}
+
+	return k[:keyLen]
 }

kdf/kdf_64bit_test.go

@@ -11,6 +11,6 @@ import (
 // This case should be failed on 32bits system.
 func TestKdfPanic(t *testing.T) {
 	shouldPanic(t, func() {
-		Kdf(sm3.New(), []byte("123456"), 1<<37)
+		Kdf(sm3.New, []byte("123456"), 1<<37)
 	})
 }

kdf/kdf_test.go

@@ -31,7 +31,7 @@ func TestKdf(t *testing.T) {
 	for _, tt := range tests {
 		wantBytes, _ := hex.DecodeString(tt.want)
 		t.Run(tt.name, func(t *testing.T) {
-			if got := Kdf(tt.args.md, tt.args.z, tt.args.len); !reflect.DeepEqual(got, wantBytes) {
+			if got := Kdf(sm3.New, tt.args.z, tt.args.len); !reflect.DeepEqual(got, wantBytes) {
 				t.Errorf("Kdf(%v) = %x, want %v", tt.name, got, tt.want)
 			}
 		})
@@ -44,7 +44,7 @@ func TestKdfOldCase(t *testing.T) {
 
 	expected := "006e30dae231b071dfad8aa379e90264491603"
 
-	result := Kdf(sm3.New(), append(x2.Bytes(), y2.Bytes()...), 19)
+	result := Kdf(sm3.New, append(x2.Bytes(), y2.Bytes()...), 19)
 
 	resultStr := hex.EncodeToString(result)
 
@@ -71,16 +71,17 @@ func BenchmarkKdf(b *testing.B) {
 		{64, 32},
 		{64, 64},
 		{64, 128},
-		{440, 32},
+		{64, 256},
+		{64, 512},
+		{64, 1024},
 	}
-	sm3Hash := sm3.New()
 	z := make([]byte, 512)
 	for _, tt := range tests {
 		b.Run(fmt.Sprintf("zLen=%v-kLen=%v", tt.zLen, tt.kLen), func(b *testing.B) {
 			b.ReportAllocs()
 			b.ResetTimer()
 			for i := 0; i < b.N; i++ {
-				Kdf(sm3Hash, z[:tt.zLen], tt.kLen)
+				Kdf(sm3.New, z[:tt.zLen], tt.kLen)
 			}
 		})
 	}

sm2/sm2.go

@@ -25,7 +25,6 @@ import (
 	"github.com/emmansun/gmsm/internal/randutil"
 	_sm2ec "github.com/emmansun/gmsm/internal/sm2ec"
 	"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"
@@ -251,7 +250,7 @@ func encryptSM2EC(c *sm2Curve, pub *ecdsa.PublicKey, random io.Reader, msg []byt
 			return nil, err
 		}
 		C2Bytes := C2.Bytes()[1:]
-		c2 := kdf.Kdf(sm3.New(), C2Bytes, len(msg))
+		c2 := sm3.Kdf(C2Bytes, len(msg))
 		if subtle.ConstantTimeAllZero(c2) {
 			retryCount++
 			if retryCount > maxRetryLimit {
@@ -424,7 +423,7 @@ func decryptSM2EC(c *sm2Curve, priv *PrivateKey, ciphertext []byte, opts *Decryp
 	}
 	C2Bytes := C2.Bytes()[1:]
 	msgLen := len(c2)
-	msg := kdf.Kdf(sm3.New(), C2Bytes, msgLen)
+	msg := sm3.Kdf(C2Bytes, msgLen)
 	if subtle.ConstantTimeAllZero(c2) {
 		return nil, ErrDecryption
 	}

sm2/sm2_keyexchange.go

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

sm2/sm2_legacy.go

@@ -11,7 +11,6 @@ import (
 	"strings"
 
 	"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"
@@ -260,7 +259,7 @@ func encryptLegacy(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *Enc
 		x2, y2 := curve.ScalarMult(pub.X, pub.Y, k.Bytes())
 
 		//A5, calculate t=KDF(x2||y2, klen)
-		c2 := kdf.Kdf(sm3.New(), append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
+		c2 := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
 		if subtle.ConstantTimeAllZero(c2) {
 			retryCount++
 			if retryCount > maxRetryLimit {
@@ -408,7 +407,7 @@ 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 := kdf.Kdf(sm3.New(), append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
+	msg := sm3.Kdf(append(toBytes(curve, x2), toBytes(curve, y2)...), msgLen)
 	if subtle.ConstantTimeAllZero(c2) {
 		return nil, ErrDecryption
 	}

sm2/sm2_test.go

@@ -851,3 +851,11 @@ func BenchmarkMoreThan32_P256(b *testing.B) {
 func BenchmarkMoreThan32_SM2(b *testing.B) {
 	benchmarkEncrypt(b, P256(), "encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard")
 }
+
+func BenchmarkEncrypt512_SM2(b *testing.B) {
+	benchmarkEncrypt(b, P256(), "encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption s")
+}
+
+func BenchmarkEncrypt1024_SM2(b *testing.B) {
+	benchmarkEncrypt(b, P256(), "encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption sencryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption s")
+}

sm3/sm3.go

@@ -211,3 +211,26 @@ func Sum(data []byte) [Size]byte {
 	d.Write(data)
 	return d.checkSum()
 }
+
+// Kdf key derivation function using SM3, compliance with GB/T 32918.4-2016 5.4.3.
+func Kdf(z []byte, keyLen int) []byte {
+	limit := uint64(keyLen+Size-1) / uint64(Size)
+	if limit >= uint64(1<<32)-1 {
+		panic("sm3: key length too long")
+	}
+	var countBytes [4]byte
+	var ct uint32 = 1
+	var k []byte
+	baseMD := new(digest)
+	baseMD.Reset()
+	baseMD.Write(z)
+	for i := 0; i < int(limit); i++ {
+		binary.BigEndian.PutUint32(countBytes[:], ct)
+		md := *baseMD
+		md.Write(countBytes[:])
+		h := md.checkSum()
+		k = append(k, h[:]...)
+		ct++
+	}
+	return k[:keyLen]
+}

sm3/sm3_test.go

@@ -9,6 +9,8 @@ import (
 	"fmt"
 	"hash"
 	"io"
+	"math/big"
+	"reflect"
 	"testing"
 
 	"golang.org/x/sys/cpu"
@@ -403,6 +405,75 @@ func BenchmarkHash8K_SH256(b *testing.B) {
 	benchmarkSize(benchSH256, b, 8192)
 }
 
+func TestKdf(t *testing.T) {
+	type args struct {
+		z   []byte
+		len int
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{"sm3 case 1", args{[]byte("emmansun"), 16}, "708993ef1388a0ae4245a19bb6c02554"},
+		{"sm3 case 2", args{[]byte("emmansun"), 32}, "708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd4"},
+		{"sm3 case 3", args{[]byte("emmansun"), 48}, "708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd47eba4fa460e7b277bc6b4ce4d07ed493"},
+		{"sm3 case 4", args{[]byte("708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd47eba4fa460e7b277bc6b4ce4d07ed493708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd47eba4fa460e7b277bc6b4ce4d07ed493"), 48}, "49cf14649f324a07e0d5bb2a00f7f05d5f5bdd6d14dff028e071327ec031104590eddb18f98b763e18bf382ff7c3875f"},
+		{"sm3 case 5", args{[]byte("708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd47eba4fa460e7b277bc6b4ce4d07ed493708993ef1388a0ae4245a19bb6c02554c632633e356ddb989beb804fda96cfd47eba4fa460e7b277bc6b4ce4d07ed493"), 128}, "49cf14649f324a07e0d5bb2a00f7f05d5f5bdd6d14dff028e071327ec031104590eddb18f98b763e18bf382ff7c3875f30277f3179baebd795e7853fa643fdf280d8d7b81a2ab7829f615e132ab376d32194cd315908d27090e1180ce442d9be99322523db5bfac40ac5acb03550f5c93e5b01b1d71f2630868909a6a1250edb"},
+	}
+	for _, tt := range tests {
+		wantBytes, _ := hex.DecodeString(tt.want)
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Kdf(tt.args.z, tt.args.len); !reflect.DeepEqual(got, wantBytes) {
+				t.Errorf("Kdf(%v) = %x, want %v", tt.name, 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(append(x2.Bytes(), y2.Bytes()...), 19)
+
+	resultStr := hex.EncodeToString(result)
+
+	if expected != resultStr {
+		t.Fatalf("expected %s, real value %s", expected, resultStr)
+	}
+}
+
+func BenchmarkKdfWithSM3(b *testing.B) {
+	tests := []struct {
+		zLen int
+		kLen int
+	}{
+		{32, 32},
+		{32, 64},
+		{32, 128},
+		{64, 32},
+		{64, 64},
+		{64, 128},
+		{64, 256},
+		{64, 512},
+		{64, 1024},
+		{64, 1024*8},
+	}
+	z := make([]byte, 512)
+	for _, tt := range tests {
+		b.Run(fmt.Sprintf("zLen=%v-kLen=%v", tt.zLen, tt.kLen), func(b *testing.B) {
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				Kdf(z[:tt.zLen], tt.kLen)
+			}
+		})
+	}
+}
+
 /*
 func round1(a, b, c, d, e, f, g, h string, i int) {
 	fmt.Printf("//Round %d\n", i+1)

sm9/sm9.go

@@ -12,7 +12,6 @@ import (
 	"github.com/emmansun/gmsm/internal/bigmod"
 	"github.com/emmansun/gmsm/internal/randutil"
 	"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"
@@ -317,7 +316,7 @@ func WrapKey(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte,
 		buffer = append(buffer, w.Marshal()...)
 		buffer = append(buffer, uid...)
 
-		key = kdf.Kdf(sm3.New(), buffer, kLen)
+		key = sm3.Kdf(buffer, kLen)
 		if !subtle.ConstantTimeAllZero(key) {
 			break
 		}
@@ -403,7 +402,7 @@ func UnwrapKey(priv *EncryptPrivateKey, uid []byte, cipher *bn256.G1, kLen int)
 	buffer = append(buffer, w.Marshal()...)
 	buffer = append(buffer, uid...)
 
-	key := kdf.Kdf(sm3.New(), buffer, kLen)
+	key := sm3.Kdf(buffer, kLen)
 	if subtle.ConstantTimeAllZero(key) {
 		return nil, ErrDecryption
 	}
@@ -685,7 +684,7 @@ func (ke *KeyExchange) generateSharedKey(isResponder bool) ([]byte, error) {
 	buffer = append(buffer, ke.g2.Marshal()...)
 	buffer = append(buffer, ke.g3.Marshal()...)
 
-	return kdf.Kdf(sm3.New(), buffer, ke.keyLength), nil
+	return sm3.Kdf(buffer, ke.keyLength), nil
 }
 
 func respondKeyExchange(ke *KeyExchange, hid byte, r *bigmod.Nat, rA *bn256.G1) (*bn256.G1, []byte, error) {

sm9/sm9_test.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/emmansun/gmsm/internal/bigmod"
 	"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"
@@ -563,7 +562,7 @@ func TestWrapKeySM9Sample(t *testing.T) {
 	buffer = append(buffer, w.Marshal()...)
 	buffer = append(buffer, uid...)
 
-	key := kdf.Kdf(sm3.New(), buffer, 32)
+	key := sm3.Kdf(buffer, 32)
 
 	if hex.EncodeToString(key) != expectedKey {
 		t.Errorf("expected %v, got %v\n", expectedKey, hex.EncodeToString(key))
@@ -629,7 +628,7 @@ func TestEncryptSM9Sample(t *testing.T) {
 	buffer = append(buffer, w.Marshal()...)
 	buffer = append(buffer, uid...)
 
-	key := kdf.Kdf(sm3.New(), buffer, len(plaintext)+32)
+	key := sm3.Kdf(buffer, len(plaintext)+32)
 
 	if hex.EncodeToString(key) != expectedKey {
 		t.Errorf("not expected key")
@@ -697,7 +696,7 @@ func TestEncryptSM9SampleBlockMode(t *testing.T) {
 	buffer = append(buffer, w.Marshal()...)
 	buffer = append(buffer, uid...)
 
-	key := kdf.Kdf(sm3.New(), buffer, 16+32)
+	key := sm3.Kdf(buffer, 16+32)
 
 	if hex.EncodeToString(key) != expectedKey {
 		t.Errorf("not expected key, expected %v, got %x\n", expectedKey, key)