generated from wyy-go/go-cli-template
/
padding.go
176 lines (145 loc) · 4.85 KB
/
padding.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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
package wcrypto
import (
"bytes"
"fmt"
)
type PaddingType string
const (
PaddingTypeNone PaddingType = "NonePadding"
PaddingTypeAnsiX923 PaddingType = "AnsiX923Padding"
PaddingTypeISO10126 PaddingType = "ISO10126Padding"
PaddingTypeISO97971 PaddingType = "ISO97971Padding"
PaddingTypePKCS7 PaddingType = "PKCS7Padding"
PaddingTypePKCS5 PaddingType = "PKCS5Padding"
PaddingTypeZero PaddingType = "ZeroPadding"
)
var paddings = map[PaddingType]Padding{
PaddingTypeNone: &NonePadding{},
PaddingTypeAnsiX923: &AnsiX923Padding{},
PaddingTypeISO10126: &ISO10126Padding{},
PaddingTypeISO97971: &ISO97971Padding{},
PaddingTypePKCS7: &PKCS7Padding{},
PaddingTypePKCS5: &PKCS5Padding{},
PaddingTypeZero: &ZeroPadding{},
}
func getPaddingByType(key PaddingType) Padding {
p, ok := paddings[key]
if !ok {
return nil
}
return p
}
type Padding interface {
Padding(ciphertext []byte, blockSize int) ([]byte, error)
UnPadding(origData []byte) ([]byte, error)
}
func padSize(dataSize, blockSize int) (padding int) {
padding = blockSize - dataSize%blockSize
return
}
type NonePadding struct {
}
func (p *NonePadding) Padding(ciphertext []byte, blockSize int) ([]byte, error) {
return ciphertext, nil
}
func (p *NonePadding) UnPadding(origData []byte) ([]byte, error) {
return origData, nil
}
type AnsiX923Padding struct {
}
// Padding ANSI X.923
func (p *AnsiX923Padding) Padding(plaintext []byte, blockSize int) ([]byte, error) {
if blockSize < 1 || blockSize > 255 {
return nil, fmt.Errorf("crypt.AnsiX923Padding blockSize is out of bounds: %d", blockSize)
}
padding := padSize(len(plaintext), blockSize)
padtext := append(bytes.Repeat([]byte{byte(0)}, padding-1), byte(padding))
return append(plaintext, padtext...), nil
}
func (p *AnsiX923Padding) UnPadding(ciphertext []byte) ([]byte, error) {
length := len(ciphertext)
unpadding := int(ciphertext[length-1])
if length-unpadding < length-2 {
pad := ciphertext[length-unpadding : length-2]
for _, v := range pad {
if int(v) != 0 {
return nil, fmt.Errorf("crypt.AnsiX923UnPadding invalid padding found")
}
}
}
return ciphertext[0 : length-unpadding], nil
}
type ISO10126Padding struct {
}
// Padding ISO10126 implements ISO 10126 byte padding. This has been withdrawn in 2007.
func (p *ISO10126Padding) Padding(plaintext []byte, blockSize int) ([]byte, error) {
if blockSize < 1 || blockSize > 256 {
return nil, fmt.Errorf("crypt.ISO10126Padding blockSize is out of bounds: %d", blockSize)
}
padding := padSize(len(plaintext), blockSize)
padtext := append([]byte(RandStringBytes(padding-1)), byte(padding))
return append(plaintext, padtext...), nil
}
func (p *ISO10126Padding) UnPadding(ciphertext []byte) ([]byte, error) {
length := len(ciphertext)
unpadding := int(ciphertext[length-1])
return ciphertext[:length-unpadding], nil
}
type ISO97971Padding struct {
}
func (p *ISO97971Padding) Padding(plaintext []byte, blockSize int) ([]byte, error) {
plaintext = append(plaintext, 0x80)
padding := blockSize - len(plaintext)%blockSize
padtext := bytes.Repeat([]byte{0}, padding)
return append(plaintext, padtext...), nil
}
func (p *ISO97971Padding) UnPadding(ciphertext []byte) ([]byte, error) {
b := bytes.TrimRightFunc(ciphertext, func(r rune) bool { return r == rune(0) })
return b[:len(b)-1], nil
}
type PKCS7Padding struct {
}
// Padding PKCS7
func (p *PKCS7Padding) Padding(plainText []byte, blockSize int) ([]byte, error) {
padding := padSize(len(plainText), blockSize)
padText := bytes.Repeat([]byte{byte(padding)}, padding)
return append(plainText, padText...), nil
}
func (p *PKCS7Padding) UnPadding(origData []byte) ([]byte, error) {
length := len(origData)
unpadding := int(origData[length-1])
var pad = origData[length-unpadding : length-1]
for _, v := range pad {
if int(v) != unpadding {
return nil, fmt.Errorf("crypt.PKCS7UnPadding invalid padding found")
}
}
return origData[:length-unpadding], nil
}
type PKCS5Padding struct {
}
func (p *PKCS5Padding) Padding(ciphertext []byte, blockSize int) ([]byte, error) {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(ciphertext, padtext...), nil
}
func (p *PKCS5Padding) UnPadding(origData []byte) ([]byte, error) {
length := len(origData)
unpadding := int(origData[length-1])
return origData[:(length - unpadding)], nil
}
// ZeroPadding
// 使用0填充有个缺点,当元数据尾部也存在0时,在unpadding时可能会存在问题
type ZeroPadding struct {
}
func (p *ZeroPadding) Padding(ciphertext []byte, blockSize int) ([]byte, error) {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{0}, padding)
return append(ciphertext, padtext...), nil
}
func (p *ZeroPadding) UnPadding(origData []byte) ([]byte, error) {
return bytes.TrimFunc(origData,
func(r rune) bool {
return r == rune(0)
}), nil
}