From f419e785669b86d8aa940f05ee8dbeffdceed6bd Mon Sep 17 00:00:00 2001 From: Sun Yimin Date: Mon, 2 Dec 2024 17:57:51 +0800 Subject: [PATCH] Support CBC-MAC and its variants #281 --- cbcmac/cbcmac.go | 391 ++++++++++++++++++++++++++++++++++++++++++ cbcmac/cbcmac_test.go | 256 +++++++++++++++++++++++++++ 2 files changed, 647 insertions(+) create mode 100644 cbcmac/cbcmac.go create mode 100644 cbcmac/cbcmac_test.go diff --git a/cbcmac/cbcmac.go b/cbcmac/cbcmac.go new file mode 100644 index 0000000..312595a --- /dev/null +++ b/cbcmac/cbcmac.go @@ -0,0 +1,391 @@ +// Package cbcmac implements the Message Authentication Code with the block chipher mechanisms. +package cbcmac + +import ( + "crypto/cipher" + + "github.com/emmansun/gmsm/internal/subtle" + "github.com/emmansun/gmsm/padding" +) + +// Reference: GB/T 15821.1-2020 Security techniques - Message authentication codes - Part 1: Mechanisms using block ciphers + +// BockCipherMAC is the interface that wraps the basic MAC method. +type BockCipherMAC interface { + // Size returns the MAC value's number of bytes. + Size() int + + // MAC calculates the MAC of the given data. + // The MAC value's number of bytes is returned by Size. + // Intercept message authentication code as needed. + MAC(src []byte) []byte +} + +// cbcmac implements the basic CBC-MAC mode of operation for block ciphers. +type cbcmac struct { + b cipher.Block + pad padding.Padding + size int +} + +// NewCBCMAC returns a CBC-MAC instance that implements the MAC with the given block cipher. +// The padding scheme is ISO/IEC 9797-1 method 2. +// GB/T 15821.1-2020 MAC scheme 1 +func NewCBCMAC(b cipher.Block, size int) BockCipherMAC { + if size <= 0 || size > b.BlockSize() { + panic("cbcmac: invalid size") + } + return &cbcmac{b: b, pad: padding.NewISO9797M2Padding(uint(b.BlockSize())), size: size} +} + +// Size returns the size of the MAC. +// The returned value is the same as the block size of the block cipher. +func (c *cbcmac) Size() int { + return c.size +} + +// MAC calculates the MAC of the given data. +// The data is padded with the padding scheme of the block cipher before processing. +func (c *cbcmac) MAC(src []byte) []byte { + src = c.pad.Pad(src) + blockSize := c.b.BlockSize() + tag := make([]byte, blockSize) + for len(src) > 0 { + subtle.XORBytes(tag, tag, src[:blockSize]) + c.b.Encrypt(tag, tag) + src = src[blockSize:] + } + return tag[:c.size] +} + +// emac implements the EMAC mode of operation for block ciphers. +type emac struct { + pad padding.Padding + b1, b2 cipher.Block + size int +} + +// NewEMAC returns an EMAC instance that implements MAC with the given block cipher. +// The padding scheme is ISO/IEC 9797-1 method 2. +// GB/T 15821.1-2020 MAC scheme 2 +func NewEMAC(creator func(key []byte) (cipher.Block, error), key1, key2 []byte, size int) BockCipherMAC { + var b1, b2 cipher.Block + var err error + if b1, err = creator(key1); err != nil { + panic(err) + } + if size <= 0 || size > b1.BlockSize() { + panic("cbcmac: invalid size") + } + if b2, err = creator(key2); err != nil { + panic(err) + } + return &emac{pad: padding.NewISO9797M2Padding(uint(b1.BlockSize())), b1: b1, b2: b2, size: size} +} + +func (e *emac) Size() int { + return e.size +} + +func (e *emac) MAC(src []byte) []byte { + src = e.pad.Pad(src) + blockSize := e.b1.BlockSize() + tag := make([]byte, blockSize) + for len(src) > 0 { + subtle.XORBytes(tag, tag, src[:blockSize]) + e.b1.Encrypt(tag, tag) + src = src[blockSize:] + } + e.b2.Encrypt(tag, tag) + return tag[:e.size] +} + +type ansiRetailMAC emac + +// NewANSIRetailMAC returns an ANSI Retail MAC instance that implements MAC with the given block cipher. +// The padding scheme is ISO/IEC 9797-1 method 2. +// GB/T 15821.1-2020 MAC scheme 3 +func NewANSIRetailMAC(creator func(key []byte) (cipher.Block, error), key1, key2 []byte, size int) BockCipherMAC { + return (*ansiRetailMAC)(NewEMAC(creator, key1, key2, size).(*emac)) +} + +func (e *ansiRetailMAC) Size() int { + return e.size +} + +func (e *ansiRetailMAC) MAC(src []byte) []byte { + src = e.pad.Pad(src) + blockSize := e.b1.BlockSize() + tag := make([]byte, blockSize) + for len(src) > 0 { + subtle.XORBytes(tag, tag, src[:blockSize]) + e.b1.Encrypt(tag, tag) + src = src[blockSize:] + } + e.b2.Decrypt(tag, tag) + e.b1.Encrypt(tag, tag) + return tag[:e.size] +} + +type macDES struct { + pad padding.Padding + b1, b2, b3 cipher.Block + size int +} + +// NewMACDES returns a MAC-DES instance that implements MAC with the given block cipher. +// The padding scheme is ISO/IEC 9797-1 method 2. +// GB/T 15821.1-2020 MAC scheme 4 +func NewMACDES(creator func(key []byte) (cipher.Block, error), key1, key2 []byte, size int) BockCipherMAC { + var b1, b2, b3 cipher.Block + var err error + if b1, err = creator(key1); err != nil { + panic(err) + } + if size <= 0 || size > b1.BlockSize() { + panic("cbcmac: invalid size") + } + if b2, err = creator(key2); err != nil { + panic(err) + } + key3 := make([]byte, len(key2)) + copy(key3, key2) + for i := 0; i < len(key3); i++ { + key3[i] ^= 0xF0 + } + if b3, err = creator(key3); err != nil { + panic(err) + } + return &macDES{pad: padding.NewISO9797M2Padding(uint(b1.BlockSize())), b1: b1, b2: b2, b3: b3, size: size} +} + +func (m *macDES) Size() int { + return m.size +} + +func (m *macDES) MAC(src []byte) []byte { + src = m.pad.Pad(src) + blockSize := m.b1.BlockSize() + tag := make([]byte, blockSize) + copy(tag, src[:blockSize]) + m.b1.Encrypt(tag, tag) + m.b3.Encrypt(tag, tag) + src = src[blockSize:] + for len(src) > 0 { + subtle.XORBytes(tag, tag, src[:blockSize]) + m.b1.Encrypt(tag, tag) + src = src[blockSize:] + } + m.b2.Encrypt(tag, tag) + return tag[:m.size] +} + +type cmac struct { + b cipher.Block + k1, k2 []byte + size int +} + +// NewCMAC returns a CMAC instance that implements MAC with the given block cipher. +// GB/T 15821.1-2020 MAC scheme 5 +func NewCMAC(b cipher.Block, size int) BockCipherMAC { + if size <= 0 || size > b.BlockSize() { + panic("cbcmac: invalid size") + } + blockSize := b.BlockSize() + k1 := make([]byte, blockSize) + k2 := make([]byte, blockSize) + b.Encrypt(k1, k1) + msb := shiftLeft(k1) + k1[len(k1)-1] ^= msb * 0b10000111 + + copy(k2, k1) + msb = shiftLeft(k2) + k2[len(k2)-1] ^= msb * 0b10000111 + + return &cmac{b: b, k1: k1, k2: k2, size: size} +} + +func (c *cmac) Size() int { + return c.size +} + +func (c *cmac) MAC(src []byte) []byte { + blockSize := c.b.BlockSize() + tag := make([]byte, blockSize) + if len(src) == 0 { + // Special-cased as a single empty partial final block. + copy(tag, c.k2) + tag[len(src)] ^= 0b10000000 + c.b.Encrypt(tag, tag) + return tag + } + for len(src) >= blockSize { + subtle.XORBytes(tag, src[:blockSize], tag) + if len(src) == blockSize { + // Final complete block. + subtle.XORBytes(tag, c.k1, tag) + } + c.b.Encrypt(tag, tag) + src = src[blockSize:] + } + if len(src) > 0 { + // Final incomplete block. + subtle.XORBytes(tag, src, tag) + subtle.XORBytes(tag, c.k2, tag) + tag[len(src)] ^= 0b10000000 + c.b.Encrypt(tag, tag) + } + return tag[:c.size] +} + +// shiftLeft sets x to x << 1, and returns MSB₁(x). +func shiftLeft(x []byte) byte { + var msb byte + for i := len(x) - 1; i >= 0; i-- { + msb, x[i] = x[i]>>7, x[i]<<1|msb + } + return msb +} + +type lmac struct { + b1, b2 cipher.Block + pad padding.Padding + size int +} + +// NewLMAC returns an LMAC instance that implements MAC with the given block cipher. +// GB/T 15821.1-2020 MAC scheme 6 +func NewLMAC(creator func(key []byte) (cipher.Block, error), key []byte, size int) BockCipherMAC { + var b, b1, b2 cipher.Block + var err error + if b, err = creator(key); err != nil { + panic(err) + } + if size <= 0 || size > b.BlockSize() { + panic("cbcmac: invalid size") + } + blockSize := b.BlockSize() + key1 := make([]byte, blockSize) + key1[blockSize-1] = 0x01 + key2 := make([]byte, blockSize) + key2[blockSize-1] = 0x02 + b.Encrypt(key1, key1) + b.Encrypt(key2, key2) + if b1, err = creator(key1); err != nil { + panic(err) + } + if b2, err = creator(key2); err != nil { + panic(err) + } + + return &lmac{b1: b1, b2: b2, pad: padding.NewISO9797M2Padding(uint(blockSize)), size: size} +} + +func (l *lmac) Size() int { + return l.b1.BlockSize() +} + +func (l *lmac) MAC(src []byte) []byte { + src = l.pad.Pad(src) + blockSize := l.b1.BlockSize() + tag := make([]byte, blockSize) + for len(src) > blockSize { + subtle.XORBytes(tag, tag, src[:blockSize]) + l.b1.Encrypt(tag, tag) + src = src[blockSize:] + } + subtle.XORBytes(tag, tag, src[:blockSize]) + l.b2.Encrypt(tag, tag) + return tag +} + +type trCBCMAC struct { + b cipher.Block + size int +} + +// NewTRCBCMAC returns a TR-CBC-MAC instance that implements MAC with the given block cipher. +// GB/T 15821.1-2020 MAC scheme 7 +func NewTRCBCMAC(b cipher.Block, size int) BockCipherMAC { + if size <= 0 || size > b.BlockSize() { + panic("cbcmac: invalid size") + } + return &trCBCMAC{b: b, size: size} +} + +func (t *trCBCMAC) Size() int { + return t.size +} + +func (t *trCBCMAC) MAC(src []byte) []byte { + blockSize := t.b.BlockSize() + tag := make([]byte, blockSize) + padded := false + if len(src) == 0 || len(src)%blockSize != 0 { + pad := padding.NewISO9797M2Padding(uint(blockSize)) + src = pad.Pad(src) + padded = true + } + for len(src) > 0 { + subtle.XORBytes(tag, tag, src[:blockSize]) + t.b.Encrypt(tag, tag) + src = src[blockSize:] + } + if padded { + return tag[blockSize-t.size:] + } + return tag[:t.size] +} + +type cbcrMAC struct { + b cipher.Block + size int +} + +// NewCBCRMAC returns a CBCRMAC instance that implements MAC with the given block cipher. +// GB/T 15821.1-2020 MAC scheme 8 +func NewCBCRMAC(b cipher.Block, size int) BockCipherMAC { + if size <= 0 || size > b.BlockSize() { + panic("cbcmac: invalid size") + } + return &cbcrMAC{b: b, size: size} +} + +func (c *cbcrMAC) Size() int { + return c.size +} + +func (c *cbcrMAC) MAC(src []byte) []byte { + blockSize := c.b.BlockSize() + tag := make([]byte, blockSize) + c.b.Encrypt(tag, tag) + padded := false + if len(src) == 0 || len(src)%blockSize != 0 { + pad := padding.NewISO9797M2Padding(uint(blockSize)) + src = pad.Pad(src) + padded = true + } + + for len(src) > blockSize { + subtle.XORBytes(tag, tag, src[:blockSize]) + c.b.Encrypt(tag, tag) + src = src[blockSize:] + } + subtle.XORBytes(tag, tag, src[:blockSize]) + if padded { + shiftLeft(tag) + } else { + shiftRight(tag) + } + c.b.Encrypt(tag, tag) + return tag[:c.size] +} + +func shiftRight(x []byte) { + var lsb byte + for i := 0; i < len(x); i++ { + lsb, x[i] = x[i]<<7, x[i]>>1|lsb + } + x[0] ^= lsb +} diff --git a/cbcmac/cbcmac_test.go b/cbcmac/cbcmac_test.go new file mode 100644 index 0000000..8f60a99 --- /dev/null +++ b/cbcmac/cbcmac_test.go @@ -0,0 +1,256 @@ +package cbcmac + +import ( + "bytes" + "testing" + + "github.com/emmansun/gmsm/sm4" +) + +func TestCBCMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message for mac"), + []byte{0x4b, 0x65, 0x53, 0xaf, 0x3c, 0x4e, 0x27, 0x44, 0x84, 0x12, 0x31, 0x5a, 0xc7, 0x84, 0x95, 0x35}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message "), + []byte{0x42, 0x1a, 0xd1, 0x69, 0x0a, 0xa1, 0x52, 0xe2, 0x84, 0x6f, 0xa2, 0xa5, 0xd8, 0x34, 0x45, 0xa9}, + }, + } + + for i, c := range cases { + block, err := sm4.NewCipher(c.key) + if err != nil { + t.Errorf("#%d: failed to create cipher: %v", i, err) + } + mac := NewCBCMAC(block, len(c.tag)) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestEMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key1 []byte + key2 []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message for mac"), + []byte{0xe4, 0x23, 0xe3, 0x55, 0x99, 0xaf, 0xd9, 0x48, 0xae, 0xc5, 0x0b, 0xde, 0xe8, 0x38, 0xe9, 0xea}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message "), + []byte{0xf0, 0x26, 0x25, 0xce, 0xad, 0x00, 0x8d, 0x4e, 0xfb, 0xf3, 0xf0, 0xb2, 0xb0, 0xc2, 0xa7, 0x5b}, + }, + } + + for i, c := range cases { + mac := NewEMAC(sm4.NewCipher, c.key1, c.key2, len(c.tag)) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestANSIRetailMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key1 []byte + key2 []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message for mac"), + []byte{0x51, 0xe9, 0x92, 0x8c, 0x22, 0x38, 0x33, 0x0c, 0x32, 0x31, 0xb8, 0x75, 0x2a, 0x9a, 0xfd, 0x7f}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message "), + []byte{0x19, 0x72, 0x47, 0x22, 0x9c, 0xe9, 0xd7, 0xb6, 0xae, 0x40, 0x5b, 0xf8, 0x85, 0xb2, 0x70, 0x57}, + }, + } + + for i, c := range cases { + mac := NewANSIRetailMAC(sm4.NewCipher, c.key1, c.key2, len(c.tag)) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestMACDES(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key1 []byte + key2 []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message for mac"), + []byte{0x7e, 0x1a, 0x9a, 0x5e, 0x0e, 0xf0, 0x94, 0x7f, 0x25, 0xcb, 0x94, 0x85, 0x26, 0x1c, 0x98, 0x5c}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte{0x41, 0x49, 0xd2, 0xad, 0xed, 0x94, 0x56, 0x68, 0x1e, 0xc8, 0xb5, 0x11, 0xd9, 0xe7, 0xee, 0x04}, + []byte("This is the test message "), + []byte{0x94, 0x94, 0x76, 0xd3, 0x5f, 0x17, 0x26, 0x1e, 0x1f, 0xb8, 0xc4, 0x39, 0x6d, 0x62, 0xdc, 0x05}, + }, + } + + for i, c := range cases { + mac := NewMACDES(sm4.NewCipher, c.key1, c.key2, 16) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestCMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message for mac"), + []byte{0x69, 0x2c, 0x43, 0x71, 0x00, 0xf3, 0xb5, 0xee, 0x2b, 0x8a, 0xbc, 0xef, 0x37, 0x3d, 0x99, 0x0c}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message "), + []byte{0x47, 0x38, 0xa6, 0xc7, 0x60, 0xb2, 0x80, 0xfc, 0x0c, 0x8a, 0x8a, 0xf3, 0x88, 0x6e, 0x9f, 0x5d}, + }, + } + for i, c := range cases { + block, err := sm4.NewCipher(c.key) + if err != nil { + t.Errorf("#%d: failed to create cipher: %v", i, err) + } + mac := NewCMAC(block, 16) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestLMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message for mac"), + []byte{0xa0, 0xc4, 0x65, 0xee, 0x58, 0x96, 0x97, 0x2f, 0x83, 0x37, 0xaa, 0x1f, 0x92, 0xc9, 0x9d, 0x10}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message "), + []byte{0x60, 0xdd, 0x95, 0x5e, 0xd0, 0xca, 0x3d, 0x7a, 0x64, 0x22, 0x71, 0x74, 0xdd, 0x98, 0xdd, 0x81}, + }, + } + + for i, c := range cases { + mac := NewLMAC(sm4.NewCipher, c.key, 16) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestTRCBCMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message for mac"), + []byte{0x16, 0xe0, 0x29, 0x04, 0xef, 0xb7, 0x65, 0xb7}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message "), + []byte{0x84, 0x6f, 0xa2, 0xa5, 0xd8, 0x34, 0x45, 0xa9}, + }, + } + + for i, c := range cases { + block, err := sm4.NewCipher(c.key) + if err != nil { + t.Errorf("#%d: failed to create cipher: %v", i, err) + } + mac := NewTRCBCMAC(block, len(c.tag)) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +} + +func TestCBCRMAC(t *testing.T) { + // Test vectors from GB/T 15821.1-2020 Appendix B. + cases := []struct { + key []byte + src []byte + tag []byte + }{ + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message for mac"), + []byte{0xe4, 0x0e, 0xd7, 0x9c, 0x31, 0x49, 0xa1, 0xc9, 0xd4, 0x2f, 0x04, 0xc4, 0x23, 0x04, 0x99, 0x35}, + }, + { + []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10}, + []byte("This is the test message "), + []byte{0xa9, 0x9d, 0x13, 0x01, 0x3e, 0x89, 0x2e, 0xe2, 0xc2, 0x5b, 0xe2, 0xda, 0xaa, 0x6c, 0x82, 0xe8}, + }, + } + + for i, c := range cases { + block, err := sm4.NewCipher(c.key) + if err != nil { + t.Errorf("#%d: failed to create cipher: %v", i, err) + } + mac := NewCBCRMAC(block, 16) + tag := mac.MAC(c.src) + if !bytes.Equal(tag, c.tag) { + t.Errorf("#%d: expect tag %x, got %x", i, c.tag, tag) + } + } +}