From 0f3af1e6a9f0aff4bfb849efee44987e003c319f Mon Sep 17 00:00:00 2001 From: Emman Date: Thu, 4 Feb 2021 12:10:24 +0800 Subject: [PATCH] MAGIC - add simple sm4 support --- sm4/block.go | 88 ++++++++++++++++++++++++++++++++++++++ sm4/cipher.go | 88 ++++++++++++++++++++++++++++++++++++++ sm4/cipher_test.go | 102 +++++++++++++++++++++++++++++++++++++++++++++ sm4/const.go | 31 ++++++++++++++ 4 files changed, 309 insertions(+) create mode 100644 sm4/block.go create mode 100644 sm4/cipher.go create mode 100644 sm4/cipher_test.go create mode 100644 sm4/const.go diff --git a/sm4/block.go b/sm4/block.go new file mode 100644 index 0000000..94c4816 --- /dev/null +++ b/sm4/block.go @@ -0,0 +1,88 @@ +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) +} diff --git a/sm4/cipher.go b/sm4/cipher.go new file mode 100644 index 0000000..85af4c9 --- /dev/null +++ b/sm4/cipher.go @@ -0,0 +1,88 @@ +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) +} diff --git a/sm4/cipher_test.go b/sm4/cipher_test.go new file mode 100644 index 0000000..6767607 --- /dev/null +++ b/sm4/cipher_test.go @@ -0,0 +1,102 @@ +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)) + } +} diff --git a/sm4/const.go b/sm4/const.go new file mode 100644 index 0000000..c5db070 --- /dev/null +++ b/sm4/const.go @@ -0,0 +1,31 @@ +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, +}