sm4: move implementation detail to internal

sm4/sm4.go

@@ -0,0 +1,31 @@
+// Package sm4 implements ShangMi(SM) sm4 symmetric encryption algorithm.
+package sm4
+
+import (
+	"crypto/cipher"
+	"strconv"
+
+	"github.com/emmansun/gmsm/internal/sm4"
+)
+
+// BlockSize the sm4 block size in bytes.
+const BlockSize = 16
+
+type KeySizeError int
+
+func (k KeySizeError) Error() string {
+	return "sm4: invalid key size " + strconv.Itoa(int(k))
+}
+
+// NewCipher creates and returns a new [cipher.Block] implementation.
+// The key argument should be the SM4 key, must be 16 bytes long.
+func NewCipher(key []byte) (cipher.Block, error) {
+	k := len(key)
+	switch k {
+	default:
+		return nil, KeySizeError(k)
+	case 16:
+		break
+	}
+	return sm4.NewCipher(key)
+}

sm4/sm4_test.go

@@ -0,0 +1,125 @@
+package sm4
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/emmansun/gmsm/internal/cryptotest"
+)
+
+type CryptTest struct {
+	key []byte
+	in  []byte
+	out []byte
+}
+
+var encryptTests = []CryptTest{
+	{
+		// Appendix 1.
+		[]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10},
+		[]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10},
+		[]byte{0x68, 0x1e, 0xdf, 0x34, 0xd2, 0x06, 0x96, 0x5e, 0x86, 0xb3, 0xe9, 0x4f, 0x53, 0x6e, 0x42, 0x46},
+	},
+}
+
+func Test_sample1(t *testing.T) {
+	src := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}
+	expected := []byte{0x68, 0x1e, 0xdf, 0x34, 0xd2, 0x06, 0x96, 0x5e, 0x86, 0xb3, 0xe9, 0x4f, 0x53, 0x6e, 0x42, 0x46}
+	c, err := NewCipher(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dst := make([]byte, 16)
+	c.Encrypt(dst, src)
+	if !reflect.DeepEqual(dst, expected) {
+		t.Errorf("expected=%x, result=%x\n", expected, dst)
+	}
+	c.Decrypt(dst, expected)
+	if !reflect.DeepEqual(dst, src) {
+		t.Errorf("expected=%x, result=%x\n", src, dst)
+	}
+}
+
+func Test_sample2(t *testing.T) {
+	src := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}
+	expected := []byte{0x59, 0x52, 0x98, 0xc7, 0xc6, 0xfd, 0x27, 0x1f, 0x04, 0x02, 0xf8, 0x04, 0xc3, 0x3d, 0x3f, 0x66}
+	c, err := NewCipher(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dst := make([]byte, 16)
+	copy(dst, src)
+	n := 1000000
+	if testing.Short() {
+		n = 1000
+		expected = []byte{215, 53, 233, 28, 197, 104, 156, 243, 18, 188, 193, 239, 183, 64, 232, 19}
+	}
+	for i := 0; i < n; i++ {
+		c.Encrypt(dst, dst)
+	}
+	if !reflect.DeepEqual(dst, expected) {
+		t.Errorf("expected=%x, result=%x\n", expected, dst)
+	}
+}
+
+func TestEncryptDecryptPanic(t *testing.T) {
+	key := make([]byte, 16)
+	src := make([]byte, 15)
+	dst := make([]byte, 16)
+	c, err := NewCipher(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	shouldPanic(t, func() { c.Encrypt(dst, src) })
+	shouldPanic(t, func() { c.Encrypt(src, dst) })
+	shouldPanic(t, func() { c.Decrypt(dst, src) })
+	shouldPanic(t, func() { c.Decrypt(src, dst) })
+
+	src = make([]byte, 32)
+	shouldPanic(t, func() { c.Encrypt(src, src[1:]) })
+	shouldPanic(t, func() { c.Encrypt(src[1:], src) })
+	shouldPanic(t, func() { c.Decrypt(src, src[1:]) })
+	shouldPanic(t, func() { c.Decrypt(src[1:], src) })
+}
+
+func shouldPanic(t *testing.T, f func()) {
+	t.Helper()
+	defer func() { _ = recover() }()
+	f()
+	t.Errorf("should have panicked")
+}
+
+// Test SM4 against the general cipher.Block interface tester
+func TestSM4Block(t *testing.T) {
+	t.Run("SM4", func(t *testing.T) {
+		cryptotest.TestBlock(t, 16, NewCipher)
+	})
+}
+
+func BenchmarkEncrypt(b *testing.B) {
+	tt := encryptTests[0]
+	c, err := NewCipher(tt.key)
+	if err != nil {
+		b.Fatal("NewCipher:", err)
+	}
+	out := make([]byte, len(tt.in))
+	b.SetBytes(int64(len(out)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		c.Encrypt(out, tt.in)
+	}
+}
+
+func BenchmarkDecrypt(b *testing.B) {
+	tt := encryptTests[0]
+	c, err := NewCipher(tt.key)
+	if err != nil {
+		b.Fatal("NewCipher:", err)
+	}
+	out := make([]byte, len(tt.out))
+	b.SetBytes(int64(len(out)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		c.Decrypt(out, tt.out)
+	}
+}