-
Notifications
You must be signed in to change notification settings - Fork 54
/
block.go
88 lines (74 loc) · 1.88 KB
/
block.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
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)
}