MAGIC - add simple sm4 support

This commit is contained in:
Emman 2021-02-04 12:10:24 +08:00
parent 462637a7fb
commit 0f3af1e6a9
4 changed files with 309 additions and 0 deletions

88
sm4/block.go Normal file
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package sm4
import (
"encoding/binary"
"math/bits"
)
type convert func(uint32) uint32
// Encrypt one block from src into dst, using the expanded key xk.
func encryptBlockGo(xk []uint32, dst, src []byte) {
_ = src[15] // early bounds check
_ = dst[15] // early bounds check
var x [rounds + 4]uint32
var i int
for i = 0; i < 4; i++ {
x[i] = binary.BigEndian.Uint32(src[4*i:])
}
for i = 0; i < rounds; i++ {
x[i+4] = x[i] ^ t(x[i+1]^x[i+2]^x[i+3]^xk[i])
}
for i = rounds + 3; i >= rounds; i-- {
binary.BigEndian.PutUint32(dst[4*(rounds+3-i):], x[i])
}
}
// Key expansion algorithm.
func expandKeyGo(key []byte, enc, dec []uint32) {
// Encryption key setup.
var i int
var mk []uint32
var k [rounds + 4]uint32
nk := len(key) / 4
mk = make([]uint32, nk)
for i = 0; i < nk; i++ {
mk[i] = binary.BigEndian.Uint32(key[4*i:])
k[i] = mk[i] ^ fk[i]
}
for i = 0; i < rounds; i++ {
k[i+4] = k[i] ^ t2(k[i+1]^k[i+2]^k[i+3]^ck[i])
enc[i] = k[i+4]
}
// Derive decryption key from encryption key.
if dec == nil {
return
}
for i = 0; i < rounds; i++ {
dec[i] = enc[rounds-1-i]
}
}
// Decrypt one block from src into dst, using the expanded key xk.
func decryptBlockGo(xk []uint32, dst, src []byte) {
encryptBlockGo(xk, dst, src)
}
//L(B)
func l(b uint32) uint32 {
return b ^ bits.RotateLeft32(b, 2) ^ bits.RotateLeft32(b, 10) ^ bits.RotateLeft32(b, 18) ^ bits.RotateLeft32(b, 24)
}
//L'(B)
func l2(b uint32) uint32 {
return b ^ bits.RotateLeft32(b, 13) ^ bits.RotateLeft32(b, 23)
}
func _t(in uint32, fn convert) uint32 {
var bytes [4]byte
binary.BigEndian.PutUint32(bytes[:], in)
for i := 0; i < 4; i++ {
bytes[i] = sbox[bytes[i]]
}
return fn(binary.BigEndian.Uint32(bytes[:]))
}
//T
func t(in uint32) uint32 {
return _t(in, l)
}
//T'
func t2(in uint32) uint32 {
return _t(in, l2)
}

88
sm4/cipher.go Normal file
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package sm4
import (
"crypto/cipher"
"fmt"
"unsafe"
)
// BlockSize the sm4 block size in bytes.
const BlockSize = 16
const rounds = 32
// A cipher is an instance of SM4 encryption using a particular key.
type sm4Cipher struct {
enc []uint32
dec []uint32
}
// NewCipher creates and returns a new cipher.Block.
// The key argument should be the SM4 key,
func NewCipher(key []byte) (cipher.Block, error) {
k := len(key)
switch k {
default:
return nil, fmt.Errorf("sm4: invalid key size %d", k)
case 16:
break
}
return newCipher(key)
}
// newCipher creates and returns a new cipher.Block
// implemented in pure Go.
func newCipher(key []byte) (cipher.Block, error) {
c := sm4Cipher{make([]uint32, rounds), make([]uint32, rounds)}
expandKeyGo(key, c.enc, c.dec)
return &c, nil
}
func (c *sm4Cipher) BlockSize() int { return BlockSize }
func (c *sm4Cipher) Encrypt(dst, src []byte) {
if len(src) < BlockSize {
panic("sm4: input not full block")
}
if len(dst) < BlockSize {
panic("sm4: output not full block")
}
if InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
panic("sm4: invalid buffer overlap")
}
encryptBlockGo(c.enc, dst, src)
}
func (c *sm4Cipher) Decrypt(dst, src []byte) {
if len(src) < BlockSize {
panic("sm4: input not full block")
}
if len(dst) < BlockSize {
panic("sm4: output not full block")
}
if InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
panic("sm4: invalid buffer overlap")
}
decryptBlockGo(c.dec, dst, src)
}
// AnyOverlap reports whether x and y share memory at any (not necessarily
// corresponding) index. The memory beyond the slice length is ignored.
func AnyOverlap(x, y []byte) bool {
return len(x) > 0 && len(y) > 0 &&
uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
}
// InexactOverlap reports whether x and y share memory at any non-corresponding
// index. The memory beyond the slice length is ignored. Note that x and y can
// have different lengths and still not have any inexact overlap.
//
// InexactOverlap can be used to implement the requirements of the crypto/cipher
// AEAD, Block, BlockMode and Stream interfaces.
func InexactOverlap(x, y []byte) bool {
if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
return false
}
return AnyOverlap(x, y)
}

102
sm4/cipher_test.go Normal file
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package sm4
import (
"crypto/cipher"
"crypto/rand"
"errors"
"fmt"
"io"
"reflect"
"testing"
)
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.Fatalf("expected=%v, result=%v\n", expected, dst)
}
c.Decrypt(dst, expected)
if !reflect.DeepEqual(dst, src) {
t.Fatalf("expected=%v, result=%v\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)
for i := 0; i < 1000000; i++ {
c.Encrypt(dst, dst)
}
if !reflect.DeepEqual(dst, expected) {
t.Fatalf("expected=%v, result=%v\n", expected, dst)
}
}
func paddingPKCS7(buf []byte, blockSize int) []byte {
bufLen := len(buf)
padLen := blockSize - bufLen%blockSize
padded := make([]byte, bufLen+padLen)
copy(padded, buf)
for i := 0; i < padLen; i++ {
padded[bufLen+i] = byte(padLen)
}
return padded
}
func unpaddingPKCS7(padded []byte, size int) ([]byte, error) {
if len(padded)%size != 0 {
return nil, errors.New("pkcs7: Padded value wasn't in correct size")
}
paddedByte := int(padded[len(padded)-1])
if (paddedByte > size) || (paddedByte < 1) {
return nil, fmt.Errorf("Invalid decrypted text, no padding")
}
bufLen := len(padded) - paddedByte
buf := make([]byte, bufLen)
copy(buf, padded[:bufLen])
return buf, nil
}
func Test_sm4withcbc_less(t *testing.T) {
src := []byte("emmansun")
key := []byte("passwordpassword")
block, err := NewCipher(key)
if err != nil {
t.Fatal(err)
}
plainText := paddingPKCS7(src, BlockSize)
cipherText := make([]byte, BlockSize+len(plainText))
iv := cipherText[:BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
t.Fatal(err)
}
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(cipherText[BlockSize:], plainText)
iv = cipherText[:BlockSize]
cipherText = cipherText[BlockSize:]
mode = cipher.NewCBCDecrypter(block, iv)
mode.CryptBlocks(cipherText, cipherText)
result, err := unpaddingPKCS7(cipherText, BlockSize)
if err != nil {
t.Fatal(err)
}
if string(result) != string(src) {
t.Fatalf("result=%s, expected=%s\n", string(result), string(src))
}
}

31
sm4/const.go Normal file
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package sm4
var sbox = [256]byte{
0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48,
}
var ck = [32]uint32{
0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269, 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249, 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229, 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209, 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279,
}
var fk = [32]uint32{
0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc,
}