sm9: support non-xor modes

cipher/ctr_sm4_test.go

@@ -8,8 +8,6 @@ import (
 	"github.com/emmansun/gmsm/sm4"
 )
 
-var commonCounter = []byte{0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff}
-
 var ctrSM4Tests = []struct {
 	name string
 	key  []byte

cipher/ecb.go

@@ -0,0 +1,99 @@
+// Electronic Code Book (ECB) mode.
+
+// Please do NOT use this mode alone.
+package cipher
+
+import (
+	goCipher "crypto/cipher"
+
+	"github.com/emmansun/gmsm/internal/alias"
+)
+
+type ecb struct {
+	b         goCipher.Block
+	blockSize int
+}
+
+func newECB(b goCipher.Block) *ecb {
+	return &ecb{
+		b:         b,
+		blockSize: b.BlockSize(),
+	}
+}
+
+func (x *ecb) validate(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("cipher: output smaller than input")
+	}
+	if alias.InexactOverlap(dst[:len(src)], src) {
+		panic("cipher: invalid buffer overlap")
+	}
+}
+
+type ecbEncrypter ecb
+
+// ecbEncAble is an interface implemented by ciphers that have a specific
+// optimized implementation of ECB encryption, like sm4.
+// NewECBEncrypter will check for this interface and return the specific
+// BlockMode if found.
+type ecbEncAble interface {
+	NewECBEncrypter() goCipher.BlockMode
+}
+
+// NewECBEncrypter returns a BlockMode which encrypts in electronic code book
+// mode, using the given Block.
+func NewECBEncrypter(b goCipher.Block) goCipher.BlockMode {
+	if ecb, ok := b.(ecbEncAble); ok {
+		return ecb.NewECBEncrypter()
+	}
+	return (*ecbEncrypter)(newECB(b))
+}
+
+func (x *ecbEncrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	(*ecb)(x).validate(dst, src)
+
+	for len(src) > 0 {
+		x.b.Encrypt(dst[:x.blockSize], src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+type ecbDecrypter ecb
+
+// ecbDecAble is an interface implemented by ciphers that have a specific
+// optimized implementation of ECB decryption, like sm4.
+// NewECBDecrypter will check for this interface and return the specific
+// BlockMode if found.
+type ecbDecAble interface {
+	NewECBDecrypter() goCipher.BlockMode
+}
+
+// NewECBDecrypter returns a BlockMode which decrypts in electronic code book
+// mode, using the given Block.
+func NewECBDecrypter(b goCipher.Block) goCipher.BlockMode {
+	if ecb, ok := b.(ecbDecAble); ok {
+		return ecb.NewECBDecrypter()
+	}
+	return (*ecbDecrypter)(newECB(b))
+}
+
+func (x *ecbDecrypter) BlockSize() int { return x.blockSize }
+
+func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
+	(*ecb)(x).validate(dst, src)
+
+	if len(src) == 0 {
+		return
+	}
+	for len(src) > 0 {
+		x.b.Decrypt(dst[:x.blockSize], src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}

cipher/ecb_sm4_test.go

@@ -0,0 +1,119 @@
+package cipher_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/emmansun/gmsm/cipher"
+	"github.com/emmansun/gmsm/sm4"
+)
+
+var ecbSM4Tests = []struct {
+	name string
+	key  []byte
+	in   []byte
+}{
+	{
+		"1 block",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintext"),
+	},
+	{
+		"2 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintext"),
+	},
+	{
+		"2 different blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextfedcba9876543210"),
+	},
+	{
+		"3 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"4 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"5 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"6 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"7 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"8 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+	{
+		"9 same blocks",
+		[]byte("0123456789ABCDEF"),
+		[]byte("exampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintextexampleplaintext"),
+	},
+}
+
+func TestECBBasic(t *testing.T) {
+	for _, test := range ecbSM4Tests {
+		c, err := sm4.NewCipher(test.key)
+		if err != nil {
+			t.Errorf("%s: NewCipher(%d bytes) = %s", test.name, len(test.key), err)
+			continue
+		}
+		encrypter := cipher.NewECBEncrypter(c)
+		ciphertext := make([]byte, len(test.in))
+		encrypter.CryptBlocks(ciphertext, test.in)
+
+		plaintext := make([]byte, len(test.in))
+		decrypter := cipher.NewECBDecrypter(c)
+		decrypter.CryptBlocks(plaintext, ciphertext)
+		if !bytes.Equal(test.in, plaintext) {
+			t.Errorf("%s: ECB encrypt/decrypt failed", test.name)
+		}
+	}
+}
+
+func shouldPanic(t *testing.T, f func()) {
+	t.Helper()
+	defer func() { _ = recover() }()
+	f()
+	t.Errorf("should have panicked")
+}
+
+func TestECBValidate(t *testing.T) {
+	key := make([]byte, 16)
+	src := make([]byte, 32)
+	c, err := sm4.NewCipher(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	decrypter := cipher.NewECBDecrypter(c)
+	// test len(src) == 0
+	decrypter.CryptBlocks(nil, nil)
+
+	// cipher: input not full blocks
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src, src[1:])
+	})
+	// cipher: output smaller than input
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src[1:], src)
+	})
+	// cipher: invalid buffer overlap
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src[1:17], src[2:18])
+	})
+}

cipher/example_test.go

@@ -0,0 +1,76 @@
+package cipher_test
+
+import (
+	"crypto/aes"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/emmansun/gmsm/cipher"
+)
+
+func ExampleNewECBEncrypter() {
+	// Load your secret key from a safe place and reuse it across multiple
+	// NewCipher calls. (Obviously don't use this example key for anything
+	// real.) If you want to convert a passphrase to a key, use a suitable
+	// package like bcrypt or scrypt.
+	key, _ := hex.DecodeString("6368616e676520746869732070617373")
+	plaintext := []byte("exampleplaintextexampleplaintext")
+
+	// ECB mode works on blocks so plaintexts may need to be padded to the
+	// next whole block. For an example of such padding, see
+	// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. Here we'll
+	// assume that the plaintext is already of the correct length.
+	if len(plaintext)%aes.BlockSize != 0 {
+		panic("plaintext is not a multiple of the block size")
+	}
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+
+	ciphertext := make([]byte, len(plaintext))
+	mode := cipher.NewECBEncrypter(block)
+	mode.CryptBlocks(ciphertext, plaintext)
+
+	// It's important to remember that ciphertexts must be authenticated
+	// (i.e. by using crypto/hmac) as well as being encrypted in order to
+	// be secure.
+
+	fmt.Printf("%x\n", ciphertext)
+}
+
+func ExampleNewECBDecrypter() {
+	// Load your secret key from a safe place and reuse it across multiple
+	// NewCipher calls. (Obviously don't use this example key for anything
+	// real.) If you want to convert a passphrase to a key, use a suitable
+	// package like bcrypt or scrypt.
+	key, _ := hex.DecodeString("6368616e676520746869732070617373")
+	ciphertext, _ := hex.DecodeString("f42512e1e4039213bd449ba47faa1b74f42512e1e4039213bd449ba47faa1b74")
+
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		panic(err)
+	}
+
+	// ECB mode always works in whole blocks.
+	if len(ciphertext)%aes.BlockSize != 0 {
+		panic("ciphertext is not a multiple of the block size")
+	}
+
+	mode := cipher.NewECBDecrypter(block)
+
+	// CryptBlocks can work in-place if the two arguments are the same.
+	mode.CryptBlocks(ciphertext, ciphertext)
+
+	// If the original plaintext lengths are not a multiple of the block
+	// size, padding would have to be added when encrypting, which would be
+	// removed at this point. For an example, see
+	// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. However, it's
+	// critical to note that ciphertexts must be authenticated (i.e. by
+	// using crypto/hmac) before being decrypted in order to avoid creating
+	// a padding oracle.
+
+	fmt.Printf("%s\n", ciphertext)
+	// Output: exampleplaintextexampleplaintext
+}

sm4/ctr_cipher_asm.go

@@ -34,7 +34,7 @@ func (c *sm4CipherAsm) NewCTR(iv []byte) cipher.Stream {
 	}
 	s := &ctr{
 		b:       c,
-		ctr:     make([]byte, c.batchBlocks*len(iv)),
+		ctr:     make([]byte, c.blocksSize),
 		out:     make([]byte, 0, bufSize),
 		outUsed: 0,
 	}

sm4/ecb_cipher_asm.go

@@ -0,0 +1,82 @@
+//go:build (amd64 && !purego) || (arm64 && !purego)
+// +build amd64,!purego arm64,!purego
+
+package sm4
+
+import (
+	"crypto/cipher"
+
+	"github.com/emmansun/gmsm/internal/alias"
+)
+
+// Assert that sm4CipherAsm implements the ecbEncAble and ecbDecAble interfaces.
+var _ ecbEncAble = (*sm4CipherAsm)(nil)
+var _ ecbDecAble = (*sm4CipherAsm)(nil)
+
+const ecbEncrypt = 1
+const ecbDecrypt = 0
+
+type ecb struct {
+	b   *sm4CipherAsm
+	enc int
+}
+
+func (x *ecb) validate(dst, src []byte) {
+	if len(src)%BlockSize != 0 {
+		panic("cipher: input not full blocks")
+	}
+	if len(dst) < len(src) {
+		panic("cipher: output smaller than input")
+	}
+	if alias.InexactOverlap(dst[:len(src)], src) {
+		panic("cipher: invalid buffer overlap")
+	}
+}
+
+func (b *sm4CipherAsm) NewECBEncrypter() cipher.BlockMode {
+	var c ecb
+	c.b = b
+	c.enc = ecbEncrypt
+	return &c
+}
+
+func (b *sm4CipherAsm) NewECBDecrypter() cipher.BlockMode {
+	var c ecb
+	c.b = b
+	c.enc = ecbDecrypt
+	return &c
+}
+
+func (x *ecb) BlockSize() int { return BlockSize }
+
+func (x *ecb) CryptBlocks(dst, src []byte) {
+	x.validate(dst, src)
+	if len(src) == 0 {
+		return
+	}
+	for len(src) >= x.b.blocksSize {
+		if x.enc == ecbEncrypt {
+			x.b.EncryptBlocks(dst[:x.b.blocksSize], src[:x.b.blocksSize])
+		} else {
+			x.b.DecryptBlocks(dst[:x.b.blocksSize], src[:x.b.blocksSize])
+		}
+		src = src[x.b.blocksSize:]
+		dst = dst[x.b.blocksSize:]
+	}
+	if len(src) > BlockSize {
+		temp := make([]byte, x.b.blocksSize)
+		copy(temp, src)
+		if x.enc == ecbEncrypt {
+			x.b.EncryptBlocks(temp, temp)
+		} else {
+			x.b.DecryptBlocks(temp, temp)
+		}
+		copy(dst, temp[:len(src)])
+	} else if len(src) > 0 {
+		if x.enc == ecbEncrypt {
+			x.b.Encrypt(dst, src)
+		} else {
+			x.b.Decrypt(dst, src)
+		}
+	}
+}

sm4/ecb_cipher_asm_test.go

@@ -0,0 +1,33 @@
+package sm4
+
+import (
+	"testing"
+
+	"github.com/emmansun/gmsm/cipher"
+)
+
+func TestECBValidate(t *testing.T) {
+	key := make([]byte, 16)
+	src := make([]byte, 32)
+	c, err := NewCipher(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	decrypter := cipher.NewECBDecrypter(c)
+	// test len(src) == 0
+	decrypter.CryptBlocks(nil, nil)
+
+	// cipher: input not full blocks
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src, src[1:])
+	})
+	// cipher: output smaller than input
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src[1:], src)
+	})
+	// cipher: invalid buffer overlap
+	shouldPanic(t, func() {
+		decrypter.CryptBlocks(src[1:17], src[2:18])
+	})
+}

sm4/modes.go

@@ -2,6 +2,20 @@ package sm4
 
 import "crypto/cipher"
 
+// ecbcEncAble is implemented by cipher.Blocks that can provide an optimized
+// implementation of ECB encryption through the cipher.BlockMode interface.
+// See crypto/ecb.go.
+type ecbEncAble interface {
+	NewECBEncrypter() cipher.BlockMode
+}
+
+// ecbDecAble is implemented by cipher.Blocks that can provide an optimized
+// implementation of ECB decryption through the cipher.BlockMode interface.
+// See crypto/ecb.go.
+type ecbDecAble interface {
+	NewECBDecrypter() cipher.BlockMode
+}
+
 // cbcEncAble is implemented by cipher.Blocks that can provide an optimized
 // implementation of CBC encryption through the cipher.BlockMode interface.
 // See crypto/cipher/cbc.go.

sm9/README.md

@@ -3,7 +3,7 @@
 2.Sign/Verify    
 3.Key Exchange  
 4.Wrap/Unwrap Key  
-5.Encryption/Decryption (XOR mode)
+5.Encryption/Decryption
 
 ## SM9 current performance:
 

sm9/example_test.go

@@ -135,7 +135,7 @@ func ExampleEncryptPrivateKey_Decrypt() {
 	}
 	uid := []byte("Bob")
 	cipherDer, _ := hex.DecodeString("307f020100034200042cb3e90b0977211597652f26ee4abbe275ccb18dd7f431876ab5d40cc2fc563d9417791c75bc8909336a4e6562450836cc863f51002e31ecf0c4aae8d98641070420638ca5bfb35d25cff7cbd684f3ed75f2d919da86a921a2e3e2e2f4cbcf583f240414b7e776811774722a8720752fb1355ce45dc3d0df")
-	plaintext, err := userKey.Decrypt(uid, cipherDer)
+	plaintext, err := userKey.Decrypt(uid, cipherDer, nil)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Error from Decrypt: %s\n", err)
 		return
@@ -156,7 +156,7 @@ func ExampleEncryptMasterPublicKey_Encrypt() {
 	hid := byte(0x03)
 	uid := []byte("Bob")
 
-	ciphertext, err := masterPubKey.Encrypt(rand.Reader, uid, hid, []byte("Chinese IBE standard"))
+	ciphertext, err := masterPubKey.Encrypt(rand.Reader, uid, hid, []byte("Chinese IBE standard"), sm9.DefaultEncrypterOpts)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Error from Encrypt: %s\n", err)
 		return

sm9/sm9.go

@@ -3,6 +3,7 @@ package sm9
 
 import (
 	"crypto"
+	"crypto/cipher"
 	goSubtle "crypto/subtle"
 	"encoding/binary"
 	"errors"
@@ -10,10 +11,13 @@ import (
 	"io"
 	"math/big"
 
+	_cipher "github.com/emmansun/gmsm/cipher"
 	"github.com/emmansun/gmsm/internal/bigmod"
 	"github.com/emmansun/gmsm/internal/subtle"
 	"github.com/emmansun/gmsm/kdf"
+	"github.com/emmansun/gmsm/padding"
 	"github.com/emmansun/gmsm/sm3"
+	"github.com/emmansun/gmsm/sm4"
 	"github.com/emmansun/gmsm/sm9/bn256"
 	"golang.org/x/crypto/cryptobyte"
 	"golang.org/x/crypto/cryptobyte/asn1"
@@ -267,7 +271,7 @@ func (pub *SignMasterPublicKey) Verify(uid []byte, hid byte, hash, sig []byte) b
 	return VerifyASN1(pub, uid, hid, hash, sig)
 }
 
-// WrapKey generate and wrap key with reciever's uid and system hid
+// WrapKey generates and wraps key with reciever's uid and system hid, returns generated key and cipher.
 func WrapKey(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, kLen int) (key []byte, cipher *bn256.G1, err error) {
 	q := pub.GenerateUserPublicKey(uid, hid)
 	var (
@@ -392,78 +396,269 @@ func (priv *EncryptPrivateKey) UnwrapKey(uid, cipherDer []byte, kLen int) ([]byt
 	return UnwrapKey(priv, uid, g, kLen)
 }
 
-// Encrypt encrypt plaintext, output ciphertext with format C1||C3||C2
-func Encrypt(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, plaintext []byte) ([]byte, error) {
-	key, cipher, err := WrapKey(rand, pub, uid, hid, len(plaintext)+sm3.Size)
+type CipherFactory func(key []byte) (cipher.Block, error)
+
+// EncrypterOpts indicate encrypt/decrypt options
+type EncrypterOpts struct {
+	EncryptType   encryptType
+	Padding       padding.Padding
+	CipherFactory CipherFactory
+	CipherKeySize int
+}
+
+type DecrypterOpts EncrypterOpts
+
+func (opts *EncrypterOpts) getKeySize(plaintext []byte) int {
+	if opts.EncryptType == ENC_TYPE_XOR {
+		return len(plaintext)
+	}
+	return opts.CipherKeySize
+}
+
+// NewEncrypterOpts creates EncrypterOpts with given parameters
+func NewEncrypterOpts(encType encryptType, padMode padding.Padding, factory CipherFactory, cipherKeySize int) *EncrypterOpts {
+	opts := new(EncrypterOpts)
+	opts.EncryptType = encType
+	opts.Padding = padMode
+	opts.CipherFactory = factory
+	opts.CipherKeySize = cipherKeySize
+	return opts
+}
+
+// DefaultEncrypterOpts default option represents XOR mode
+var DefaultEncrypterOpts = NewEncrypterOpts(ENC_TYPE_XOR, nil, nil, 0)
+
+// SM4ECBEncrypterOpts option represents SM4 ECB mode
+var SM4ECBEncrypterOpts = NewEncrypterOpts(ENC_TYPE_ECB, padding.NewPKCS7Padding(sm4.BlockSize), sm4.NewCipher, sm4.BlockSize)
+
+// SM4CBCEncrypterOpts option represents SM4 CBC mode
+var SM4CBCEncrypterOpts = NewEncrypterOpts(ENC_TYPE_CBC, padding.NewPKCS7Padding(sm4.BlockSize), sm4.NewCipher, sm4.BlockSize)
+
+// SM4CFBEncrypterOpts option represents SM4 CFB mode
+var SM4CFBEncrypterOpts = NewEncrypterOpts(ENC_TYPE_CFB, padding.NewPKCS7Padding(sm4.BlockSize), sm4.NewCipher, sm4.BlockSize)
+
+// SM4OFBEncrypterOpts option represents SM4 OFB mode
+var SM4OFBEncrypterOpts = NewEncrypterOpts(ENC_TYPE_OFB, padding.NewPKCS7Padding(sm4.BlockSize), sm4.NewCipher, sm4.BlockSize)
+
+// Encrypt encrypt plaintext, output ciphertext with format C1||C3||C2.
+func Encrypt(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, plaintext []byte, opts *EncrypterOpts) ([]byte, error) {
+	c1, c2, c3, err := encrypt(rand, pub, uid, hid, plaintext, opts)
 	if err != nil {
 		return nil, err
 	}
-	subtle.XORBytes(key, key[:len(plaintext)], plaintext)
+	ciphertext := append(c1.Marshal(), c3...)
+	ciphertext = append(ciphertext, c2...)
+	return ciphertext, nil
+}
+
+func encrypt(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, plaintext []byte, opts *EncrypterOpts) (c1 *bn256.G1, c2, c3 []byte, err error) {
+	if opts == nil {
+		opts = DefaultEncrypterOpts
+	}
+	key1Len := opts.getKeySize(plaintext)
+	key, c1, err := WrapKey(rand, pub, uid, hid, key1Len+sm3.Size)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	c2, err = encryptPlaintext(rand, key[:key1Len], plaintext, opts)
+	if err != nil {
+		return nil, nil, nil, err
+	}
 
 	hash := sm3.New()
-	hash.Write(key)
-	c3 := hash.Sum(nil)
+	hash.Write(c2)
+	hash.Write(key[key1Len:])
+	c3 = hash.Sum(nil)
 
-	ciphertext := append(cipher.Marshal(), c3...)
-	ciphertext = append(ciphertext, key[:len(plaintext)]...)
-	return ciphertext, nil
+	return
+}
+
+func encryptPlaintext(rand io.Reader, key, plaintext []byte, opts *EncrypterOpts) ([]byte, error) {
+	switch opts.EncryptType {
+	case ENC_TYPE_XOR:
+		subtle.XORBytes(key, key, plaintext)
+		return key, nil
+	case ENC_TYPE_ECB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		paddedPlainText := opts.Padding.Pad(plaintext)
+		ciphertext := make([]byte, len(paddedPlainText))
+		mode := _cipher.NewECBEncrypter(block)
+		mode.CryptBlocks(ciphertext, paddedPlainText)
+		return ciphertext, nil
+	case ENC_TYPE_CBC:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		paddedPlainText := opts.Padding.Pad(plaintext)
+		blockSize := block.BlockSize()
+		ciphertext := make([]byte, blockSize+len(paddedPlainText))
+		iv := ciphertext[:blockSize]
+		if _, err := io.ReadFull(rand, iv); err != nil {
+			return nil, err
+		}
+		mode := cipher.NewCBCEncrypter(block, iv)
+		mode.CryptBlocks(ciphertext[blockSize:], paddedPlainText)
+		return ciphertext, nil
+	case ENC_TYPE_CFB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		blockSize := block.BlockSize()
+		ciphertext := make([]byte, blockSize+len(plaintext))
+		iv := ciphertext[:blockSize]
+		if _, err := io.ReadFull(rand, iv); err != nil {
+			return nil, err
+		}
+		stream := cipher.NewCFBEncrypter(block, iv)
+		stream.XORKeyStream(ciphertext[blockSize:], plaintext)
+		return ciphertext, nil
+	case ENC_TYPE_OFB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		blockSize := block.BlockSize()
+		ciphertext := make([]byte, blockSize+len(plaintext))
+		iv := ciphertext[:blockSize]
+		if _, err := io.ReadFull(rand, iv); err != nil {
+			return nil, err
+		}
+		stream := cipher.NewOFB(block, iv)
+		stream.XORKeyStream(ciphertext[blockSize:], plaintext)
+		return ciphertext, nil
+	}
+	return nil, fmt.Errorf("sm9: unsupported encryption type <%v>", opts.EncryptType)
 }
 
 // EncryptASN1 encrypt plaintext and output ciphertext with ASN.1 format according
 // SM9 cryptographic algorithm application specification, SM9Cipher definition.
-func EncryptASN1(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, plaintext []byte) ([]byte, error) {
-	return pub.Encrypt(rand, uid, hid, plaintext)
+func EncryptASN1(rand io.Reader, pub *EncryptMasterPublicKey, uid []byte, hid byte, plaintext []byte, opts *EncrypterOpts) ([]byte, error) {
+	return pub.Encrypt(rand, uid, hid, plaintext, opts)
 }
 
 // Encrypt encrypt plaintext and output ciphertext with ASN.1 format according
 // SM9 cryptographic algorithm application specification, SM9Cipher definition.
-func (pub *EncryptMasterPublicKey) Encrypt(rand io.Reader, uid []byte, hid byte, plaintext []byte) ([]byte, error) {
-	key, cipher, err := WrapKey(rand, pub, uid, hid, len(plaintext)+sm3.Size)
+func (pub *EncryptMasterPublicKey) Encrypt(rand io.Reader, uid []byte, hid byte, plaintext []byte, opts *EncrypterOpts) ([]byte, error) {
+	if opts == nil {
+		opts = DefaultEncrypterOpts
+	}
+	c1, c2, c3, err := encrypt(rand, pub, uid, hid, plaintext, opts)
 	if err != nil {
 		return nil, err
 	}
-	subtle.XORBytes(key, key[:len(plaintext)], plaintext)
-
-	hash := sm3.New()
-	hash.Write(key)
-	c3 := hash.Sum(nil)
 
 	var b cryptobyte.Builder
 	b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
-		b.AddASN1Int64(int64(ENC_TYPE_XOR))
-		b.AddASN1BitString(cipher.MarshalUncompressed())
+		b.AddASN1Int64(int64(opts.EncryptType))
+		b.AddASN1BitString(c1.MarshalUncompressed())
 		b.AddASN1OctetString(c3)
-		b.AddASN1OctetString(key[:len(plaintext)])
+		b.AddASN1OctetString(c2)
 	})
 	return b.Bytes()
 }
 
 // Decrypt decrypt chipher, ciphertext should be with format C1||C3||C2
-func Decrypt(priv *EncryptPrivateKey, uid, ciphertext []byte) ([]byte, error) {
+func Decrypt(priv *EncryptPrivateKey, uid, ciphertext []byte, opts *EncrypterOpts) ([]byte, error) {
+	if opts == nil {
+		opts = DefaultEncrypterOpts
+	}
+
 	c := &bn256.G1{}
-	c3, err := c.Unmarshal(ciphertext)
+	c3c2, err := c.Unmarshal(ciphertext)
 	if err != nil {
 		return nil, ErrDecryption
 	}
 
-	key, err := UnwrapKey(priv, uid, c, len(c3))
+	c2 := c3c2[sm3.Size:]
+	key1Len := opts.getKeySize(c2)
+
+	key, err := UnwrapKey(priv, uid, c, key1Len+sm3.Size)
 	if err != nil {
 		return nil, err
 	}
 
-	c2 := c3[sm3.Size:]
+	return decrypt(c, key[:key1Len], key[key1Len:], c2, c3c2[:sm3.Size], opts)
+}
 
+func decrypt(cipher *bn256.G1, key1, key2, c2, c3 []byte, opts *EncrypterOpts) ([]byte, error) {
 	hash := sm3.New()
 	hash.Write(c2)
-	hash.Write(key[len(c2):])
+	hash.Write(key2)
 	c32 := hash.Sum(nil)
 
-	if goSubtle.ConstantTimeCompare(c3[:sm3.Size], c32) != 1 {
+	if goSubtle.ConstantTimeCompare(c3, c32) != 1 {
 		return nil, ErrDecryption
 	}
 
-	subtle.XORBytes(key, c2, key[:len(c2)])
-	return key[:len(c2)], nil
+	return decryptCiphertext(key1, c2, opts)
+}
+
+func decryptCiphertext(key, ciphertext []byte, opts *EncrypterOpts) ([]byte, error) {
+	switch opts.EncryptType {
+	case ENC_TYPE_XOR:
+		subtle.XORBytes(key, ciphertext, key)
+		return key, nil
+	case ENC_TYPE_ECB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		plaintext := make([]byte, len(ciphertext))
+		mode := _cipher.NewECBDecrypter(block)
+		mode.CryptBlocks(plaintext, ciphertext)
+		return opts.Padding.Unpad(plaintext)
+	case ENC_TYPE_CBC:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		blockSize := block.BlockSize()
+		if len(ciphertext) < blockSize {
+			return nil, ErrDecryption
+		}
+		iv := ciphertext[:blockSize]
+		ciphertext = ciphertext[blockSize:]
+		plaintext := make([]byte, len(ciphertext))
+		mode := cipher.NewCBCDecrypter(block, iv)
+		mode.CryptBlocks(plaintext, ciphertext)
+		return opts.Padding.Unpad(plaintext)
+	case ENC_TYPE_CFB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		blockSize := block.BlockSize()
+		if len(ciphertext) < blockSize {
+			return nil, ErrDecryption
+		}
+		iv := ciphertext[:blockSize]
+		ciphertext = ciphertext[blockSize:]
+		plaintext := make([]byte, len(ciphertext))
+		stream := cipher.NewCFBDecrypter(block, iv)
+		stream.XORKeyStream(plaintext, ciphertext)
+		return plaintext, nil
+	case ENC_TYPE_OFB:
+		block, err := opts.CipherFactory(key)
+		if err != nil {
+			return nil, err
+		}
+		blockSize := block.BlockSize()
+		if len(ciphertext) < blockSize {
+			return nil, ErrDecryption
+		}
+		iv := ciphertext[:blockSize]
+		ciphertext = ciphertext[blockSize:]
+		plaintext := make([]byte, len(ciphertext))
+		stream := cipher.NewOFB(block, iv)
+		stream.XORKeyStream(plaintext, ciphertext)
+		return plaintext, nil
+	}
+	return nil, fmt.Errorf("sm9: unsupported encryption type <%v>", opts.EncryptType)
 }
 
 // DecryptASN1 decrypt chipher, ciphertext should be with ASN.1 format according
@@ -489,39 +684,30 @@ func DecryptASN1(priv *EncryptPrivateKey, uid, ciphertext []byte) ([]byte, error
 		!inner.Empty() {
 		return nil, errors.New("sm9: invalid ciphertext asn.1 data")
 	}
-	if encType != int(ENC_TYPE_XOR) {
-		return nil, fmt.Errorf("sm9: does not support this kind of encrypt type <%v> yet", encType)
-	}
+	// We just make assumption block cipher is SM4 and padding scheme is pkcs7
+	opts := NewEncrypterOpts(encryptType(encType), padding.NewPKCS7Padding(sm4.BlockSize), sm4.NewCipher, sm4.BlockSize)
 	c, err := unmarshalG1(c1Bytes)
 	if err != nil {
 		return nil, ErrDecryption
 	}
 
-	key, err := UnwrapKey(priv, uid, c, len(c2Bytes)+len(c3Bytes))
+	key1Len := opts.getKeySize(c2Bytes)
+	key, err := UnwrapKey(priv, uid, c, key1Len+sm3.Size)
 	if err != nil {
 		return nil, err
 	}
 
-	hash := sm3.New()
-	hash.Write(c2Bytes)
-	hash.Write(key[len(c2Bytes):])
-	c32 := hash.Sum(nil)
-
-	if goSubtle.ConstantTimeCompare(c3Bytes, c32) != 1 {
-		return nil, ErrDecryption
-	}
-	subtle.XORBytes(key, c2Bytes, key[:len(c2Bytes)])
-	return key[:len(c2Bytes)], nil
+	return decrypt(c, key[:key1Len], key[key1Len:], c2Bytes, c3Bytes, opts)
 }
 
 // Decrypt decrypt chipher, ciphertext should be with ASN.1 format according
 // SM9 cryptographic algorithm application specification, SM9Cipher definition.
-func (priv *EncryptPrivateKey) Decrypt(uid, ciphertext []byte) ([]byte, error) {
+func (priv *EncryptPrivateKey) Decrypt(uid, ciphertext []byte, opts *EncrypterOpts) ([]byte, error) {
 	if ciphertext[0] == 0x30 { // should be ASN.1 format
 		return DecryptASN1(priv, uid, ciphertext)
 	}
 	// fallback to C1||C3||C2 raw format
-	return Decrypt(priv, uid, ciphertext)
+	return Decrypt(priv, uid, ciphertext, opts)
 }
 
 // KeyExchange key exchange struct, include internal stat in whole key exchange flow.

sm9/sm9_test.go

@@ -659,26 +659,31 @@ func TestEncryptDecrypt(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext)
-	if err != nil {
-		t.Fatal(err)
+	encTypes := []*EncrypterOpts{
+		DefaultEncrypterOpts, SM4ECBEncrypterOpts, SM4CBCEncrypterOpts, SM4CFBEncrypterOpts, SM4OFBEncrypterOpts,
 	}
+	for _, opts := range encTypes {
+		cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext, opts)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-	got, err := Decrypt(userKey, uid, cipher)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if string(got) != string(plaintext) {
-		t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
-	}
+		got, err := Decrypt(userKey, uid, cipher, opts)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if string(got) != string(plaintext) {
+			t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		}
 
-	got, err = userKey.Decrypt(uid, cipher)
-	if err != nil {
-		t.Fatal(err)
-	}
+		got, err = userKey.Decrypt(uid, cipher, opts)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-	if string(got) != string(plaintext) {
-		t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		if string(got) != string(plaintext) {
+			t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		}
 	}
 }
 
@@ -694,27 +699,32 @@ func TestEncryptDecryptASN1(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	cipher, err := EncryptASN1(rand.Reader, masterKey.Public(), uid, hid, plaintext)
-	if err != nil {
-		t.Fatal(err)
+	encTypes := []*EncrypterOpts{
+		DefaultEncrypterOpts, SM4ECBEncrypterOpts, SM4CBCEncrypterOpts, SM4CFBEncrypterOpts, SM4OFBEncrypterOpts,
 	}
+	for _, opts := range encTypes {
+		cipher, err := EncryptASN1(rand.Reader, masterKey.Public(), uid, hid, plaintext, opts)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-	got, err := DecryptASN1(userKey, uid, cipher)
-	if err != nil {
-		t.Fatal(err)
-	}
+		got, err := DecryptASN1(userKey, uid, cipher)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-	if string(got) != string(plaintext) {
-		t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
-	}
+		if string(got) != string(plaintext) {
+			t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		}
 
-	got, err = userKey.Decrypt(uid, cipher)
-	if err != nil {
-		t.Fatal(err)
-	}
+		got, err = userKey.Decrypt(uid, cipher, opts)
+		if err != nil {
+			t.Fatal(err)
+		}
 
-	if string(got) != string(plaintext) {
-		t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		if string(got) != string(plaintext) {
+			t.Errorf("expected %v, got %v\n", string(plaintext), string(got))
+		}
 	}
 }
 
@@ -782,7 +792,7 @@ func BenchmarkEncrypt(b *testing.B) {
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext)
+		cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext, nil)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -803,14 +813,14 @@ func BenchmarkDecrypt(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext)
+	cipher, err := Encrypt(rand.Reader, masterKey.Public(), uid, hid, plaintext, nil)
 	if err != nil {
 		b.Fatal(err)
 	}
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		got, err := Decrypt(userKey, uid, cipher)
+		got, err := Decrypt(userKey, uid, cipher, nil)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -832,7 +842,7 @@ func BenchmarkDecryptASN1(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
-	cipher, err := EncryptASN1(rand.Reader, masterKey.Public(), uid, hid, plaintext)
+	cipher, err := EncryptASN1(rand.Reader, masterKey.Public(), uid, hid, plaintext, nil)
 	if err != nil {
 		b.Fatal(err)
 	}