feat: Add SM4 encryption and HMAC calculation

- Add the `HMAC` function to calculate the HMAC value of a given key and data.
- Add encryption and decryption functions with the SM4 algorithm.
- Add tests for the encryption and decryption functions in the `smtongsuo` package.

crypto/aes.go

@@ -3,6 +3,8 @@ package crypto
 import (
 	"crypto/aes"
 	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/sha256"
 	"io"
 	"os"
 	"strings"
@@ -325,3 +327,13 @@ func AESEncryptFilesInDir(dir string, secret []byte, opts ...AESEncryptFilesInDi
 
 	return pool.Wait()
 }
+
+// HMAC calculate HMAC
+func HMAC(key, data []byte) ([]byte, error) {
+	h := hmac.New(sha256.New, key)
+	if _, err := h.Write(data); err != nil {
+		return nil, errors.Wrap(err, "write data")
+	}
+
+	return h.Sum(nil), nil
+}

crypto/aes_test.go

@@ -241,3 +241,18 @@ func TestGcmIvLength(t *testing.T) {
 		require.Equal(t, AesGcmTagLen, gcm.Overhead())
 	}
 }
+
+func TestHMAC(t *testing.T) {
+	t.Parallel()
+
+	key := []byte("secret-key")
+	data := []byte("hello world")
+
+	expected := []byte{0x9, 0x5d, 0x5a, 0x21, 0xfe, 0x6d, 0x6, 0x46, 0xdb, 0x22, 0x3f, 0xdf, 0x3d, 0xe6, 0x43, 0x6b, 0xb8, 0xdf, 0xb2, 0xfa, 0xb0, 0xb5, 0x16, 0x77, 0xec, 0xf6, 0x44, 0x1f, 0xcf, 0x5f, 0x2a, 0x67}
+
+	for i := 0; i < 5; i++ {
+		result, err := HMAC(key, data)
+		require.NoError(t, err)
+		require.Equal(t, expected, result)
+	}
+}

crypto/smtongsuo.go

@@ -3,6 +3,7 @@ package crypto
 import (
 	"bytes"
 	"context"
+	"encoding/hex"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -253,3 +254,68 @@ func (t *Tongsuo) NewX509CertByCSR(ctx context.Context,
 
 	return certDer, nil
 }
+
+func (t *Tongsuo) EncryptBySm4Baisc(ctx context.Context, key, plaintext, iv []byte) (ciphertext, hmac []byte, err error) {
+	dir, err := os.MkdirTemp("", "tongsuo*")
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "generate tem dir")
+	}
+	defer t.removeAll(dir)
+
+	cipherPath := filepath.Join(dir, "cipher")
+	if _, err = t.runCMD(ctx, []string{
+		"enc", "-sm4-cbc", "-e",
+		"-in", "/dev/stdin", "-out", cipherPath,
+		"-K", hex.EncodeToString(key), "-iv", hex.EncodeToString(iv),
+	}, plaintext); err != nil {
+		return nil, nil, errors.Wrap(err, "encrypt")
+	}
+
+	if ciphertext, err = os.ReadFile(cipherPath); err != nil {
+		return nil, nil, errors.Wrap(err, "read cipher")
+	}
+
+	if hmac, err = HMAC(key, ciphertext); err != nil {
+		return nil, nil, errors.Wrap(err, "calculate hmac")
+	}
+
+	return ciphertext, hmac, nil
+}
+
+// DecryptBySm4Baisc decrypt by sm4
+//
+// # Args
+//   - key: sm4 key
+//   - ciphertext: sm4 encrypted data
+//   - iv: sm4 iv
+//   - hmac: if not nil, will check ciphertext's integrity by hmac
+func (t *Tongsuo) DecryptBySm4Baisc(ctx context.Context, key, ciphertext, iv, hmac []byte) (plaintext []byte, err error) {
+	if len(hmac) != 0 { // check hmac
+		if expectedHmac, err := HMAC(key, ciphertext); err != nil {
+			return nil, errors.Wrap(err, "calculate hmac")
+		} else if !bytes.Equal(hmac, expectedHmac) {
+			return nil, errors.Errorf("hmac not match")
+		}
+	}
+
+	dir, err := os.MkdirTemp("", "tongsuo*")
+	if err != nil {
+		return nil, errors.Wrap(err, "generate tem dir")
+	}
+	defer t.removeAll(dir)
+
+	cipherPath := filepath.Join(dir, "cipher")
+	if err = os.WriteFile(cipherPath, ciphertext, 0600); err != nil {
+		return nil, errors.Wrap(err, "write cipher")
+	}
+
+	if plaintext, err = t.runCMD(ctx, []string{
+		"enc", "-sm4-cbc", "-d",
+		"-in", cipherPath, "-out", "/dev/stdout",
+		"-K", hex.EncodeToString(key), "-iv", hex.EncodeToString(iv),
+	}, ciphertext); err != nil {
+		return nil, errors.Wrap(err, "decrypt")
+	}
+
+	return plaintext, nil
+}

crypto/smtongsuo_test.go

@@ -155,3 +155,55 @@ func TestTongsuo_NewIntermediaCaByCsr(t *testing.T) {
 		require.Contains(t, certinfo, "Issuer: CN = test-common-name")
 	})
 }
+
+func TestTongsuo_EncryptBySm4Baisc(t *testing.T) {
+	t.Parallel()
+	if testSkipSmTongsuo(t) {
+		return
+	}
+
+	ctx := context.Background()
+	ins, err := NewTongsuo("/usr/local/bin/tongsuo")
+	require.NoError(t, err)
+
+	key, err := Salt(16)
+	require.NoError(t, err)
+	incorrectKey, err := Salt(16)
+	require.NoError(t, err)
+	plaintext := []byte("Hello, World!")
+	iv, err := Salt(16)
+	require.NoError(t, err)
+
+	t.Run("correct passphare", func(t *testing.T) {
+		t.Parallel()
+
+		ciphertext, tag, err := ins.EncryptBySm4Baisc(ctx, key, plaintext, iv)
+		require.NoError(t, err)
+		require.NotNil(t, ciphertext)
+
+		// Decrypt the ciphertext to verify the encryption
+		decrypted, err := ins.DecryptBySm4Baisc(ctx, key, ciphertext, iv, tag)
+		require.NoError(t, err)
+		require.Equal(t, plaintext, decrypted)
+	})
+
+	t.Run("incorrect passphare", func(t *testing.T) {
+		t.Parallel()
+
+		ciphertext, tag, err := ins.EncryptBySm4Baisc(ctx, key, plaintext, iv)
+		require.NoError(t, err)
+		require.NotNil(t, ciphertext)
+
+		// Decrypt the ciphertext with incorrect key
+		_, err = ins.DecryptBySm4Baisc(ctx, []byte("incorrect key"), ciphertext, iv, tag)
+		require.ErrorContains(t, err, "hmac not match")
+
+		// Decrypt the ciphertext with incorrect tag
+		_, err = ins.DecryptBySm4Baisc(ctx, key, ciphertext, iv, []byte("incorrect tag"))
+		require.ErrorContains(t, err, "hmac not match")
+
+		// Decrypt the ciphertext with incorrect key and empty tag
+		_, err = ins.DecryptBySm4Baisc(ctx, incorrectKey, ciphertext, iv, nil)
+		require.ErrorContains(t, err, "got bad decrypt")
+	})
+}