-
Notifications
You must be signed in to change notification settings - Fork 22
/
rabbit.go
153 lines (134 loc) · 4.45 KB
/
rabbit.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
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
package rabbitio
import (
"errors"
"math/bits"
"crypto/cipher"
"encoding/binary"
)
var (
invalidKeyLenErr = errors.New("cryptobin/rabbitio: key must be 16 byte len, not more not less")
invalidIVXLenErr = errors.New("cryptobin/rabbitio: iv must be 8 byte len or nothing (zero) at all")
)
var aro = []uint32{
0x4D34D34D, 0xD34D34D3, 0x34D34D34, 0x4D34D34D,
0xD34D34D3, 0x34D34D34, 0x4D34D34D, 0xD34D34D3,
}
type rabbitCipher struct {
xbit [8]uint32
cbit [8]uint32
ks []byte
carry uint32
sbit [16]byte
}
// NewCipher returns a chpher.Stream interface that implemented an XORKeyStream method
// according to RFC 4503, key must be 16 byte len, iv on the other hand is optional but
// must be either zero len or 8 byte len, error will be returned on wrong key/iv len
func NewCipher(key []byte, iv []byte) (cipher.Stream, error) {
if len(key) != 16 {
return nil, invalidKeyLenErr
}
if len(iv) != 0 && len(iv) != 8 {
return nil, invalidIVXLenErr
}
var k [4]uint32
for i := range k {
k[i] = binary.LittleEndian.Uint32(key[i*4:])
}
var r rabbitCipher
r.setupKey(k[:])
if len(iv) != 0 {
var v [4]uint16
for i := range v {
v[i] = binary.LittleEndian.Uint16(iv[i*2:])
}
r.setupIV(v[:])
}
return &r, nil
}
// XORKeyStream read from src and perform xor on every elemnt of src and
// write result on dst
func (r *rabbitCipher) XORKeyStream(dst, src []byte) {
for i := range src {
if len(r.ks) == 0 {
r.extract()
}
dst[i] = src[i] ^ r.ks[0]
r.ks = r.ks[1:]
}
}
func (r *rabbitCipher) setupKey(key []uint32) {
r.xbit[0] = key[0]
r.xbit[1] = key[3]<<16 | key[2]>>16
r.xbit[2] = key[1]
r.xbit[3] = key[0]<<16 | key[3]>>16
r.xbit[4] = key[2]
r.xbit[5] = key[1]<<16 | key[0]>>16
r.xbit[6] = key[3]
r.xbit[7] = key[2]<<16 | key[1]>>16
r.cbit[0] = bits.RotateLeft32(key[2], 16)
r.cbit[1] = key[0]&0xffff0000 | key[1]&0xffff
r.cbit[2] = bits.RotateLeft32(key[3], 16)
r.cbit[3] = key[1]&0xffff0000 | key[2]&0xffff
r.cbit[4] = bits.RotateLeft32(key[0], 16)
r.cbit[5] = key[2]&0xffff0000 | key[3]&0xffff
r.cbit[6] = bits.RotateLeft32(key[1], 16)
r.cbit[7] = key[3]&0xffff0000 | key[0]&0xffff
for i := 0; i < 4; i++ {
r.nextState()
}
r.cbit[0] ^= r.xbit[4]
r.cbit[1] ^= r.xbit[5]
r.cbit[2] ^= r.xbit[6]
r.cbit[3] ^= r.xbit[7]
r.cbit[4] ^= r.xbit[0]
r.cbit[5] ^= r.xbit[1]
r.cbit[6] ^= r.xbit[2]
r.cbit[7] ^= r.xbit[3]
}
func (r *rabbitCipher) setupIV(iv []uint16) {
r.cbit[0] ^= uint32(iv[1])<<16 | uint32(iv[0])
r.cbit[1] ^= uint32(iv[3])<<16 | uint32(iv[1])
r.cbit[2] ^= uint32(iv[3])<<16 | uint32(iv[2])
r.cbit[3] ^= uint32(iv[2])<<16 | uint32(iv[0])
r.cbit[4] ^= uint32(iv[1])<<16 | uint32(iv[0])
r.cbit[5] ^= uint32(iv[3])<<16 | uint32(iv[1])
r.cbit[6] ^= uint32(iv[3])<<16 | uint32(iv[2])
r.cbit[7] ^= uint32(iv[2])<<16 | uint32(iv[0])
for i := 0; i < 4; i++ {
r.nextState()
}
}
func (r *rabbitCipher) nextState() {
var GRX [8]uint32
for i := range r.cbit {
r.carry, r.cbit[i] = bits.Sub32(aro[i], r.cbit[i], r.carry)
}
for i := range GRX {
GRX[i] = gfunction(r.xbit[i], r.cbit[i])
}
r.xbit[0x00] = GRX[0] + bits.RotateLeft32(GRX[7], 16) + bits.RotateLeft32(GRX[6], 16)
r.xbit[0x01] = GRX[1] + bits.RotateLeft32(GRX[0], 8) + GRX[7]
r.xbit[0x02] = GRX[2] + bits.RotateLeft32(GRX[1], 16) + bits.RotateLeft32(GRX[0], 16)
r.xbit[0x03] = GRX[3] + bits.RotateLeft32(GRX[2], 8) + GRX[1]
r.xbit[0x04] = GRX[4] + bits.RotateLeft32(GRX[3], 16) + bits.RotateLeft32(GRX[2], 16)
r.xbit[0x05] = GRX[5] + bits.RotateLeft32(GRX[4], 8) + GRX[3]
r.xbit[0x06] = GRX[6] + bits.RotateLeft32(GRX[5], 16) + bits.RotateLeft32(GRX[4], 16)
r.xbit[0x07] = GRX[7] + bits.RotateLeft32(GRX[6], 8) + GRX[5]
}
func (r *rabbitCipher) extract() {
var sw [4]uint32
r.nextState()
sw[0] = r.xbit[0] ^ (r.xbit[5]>>16 | r.xbit[3]<<16)
sw[1] = r.xbit[2] ^ (r.xbit[7]>>16 | r.xbit[5]<<16)
sw[2] = r.xbit[4] ^ (r.xbit[1]>>16 | r.xbit[7]<<16)
sw[3] = r.xbit[6] ^ (r.xbit[3]>>16 | r.xbit[1]<<16)
for i := range sw {
binary.LittleEndian.PutUint32(r.sbit[i*4:], sw[i])
}
r.ks = r.sbit[:]
}
func gfunction(u, v uint32) uint32 {
uv := uint64(u + v)
uv *= uv
return uint32(uv>>32) ^ uint32(uv)
}