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
|
package ext
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/gob"
"errors"
"io"
)
type Token struct {
UserID uint
Username string
}
func ReadToken(data []byte, key []byte) (*Token, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
panic(err.Error())
}
nonceSize := aesgcm.NonceSize()
if len(data) < nonceSize {
return nil, errors.New("nonce size greater than data's size")
}
nonce, ciphertext := data[:nonceSize], data[nonceSize:]
plaintext, err := aesgcm.Open(nil, nonce, ciphertext, nil)
if err != nil {
return nil, err
}
r := bytes.NewReader(plaintext)
var token Token
dec := gob.NewDecoder(r)
if err = dec.Decode(&token); err != nil {
return nil, err
}
return &token, nil
}
func WriteToken(token *Token, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
var buffer bytes.Buffer
enc := gob.NewEncoder(&buffer)
if err := enc.Encode(token); err != nil {
return nil, err
}
nonce := make([]byte, aesgcm.NonceSize())
if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
return nil, err
}
ciphertext := aesgcm.Seal(nonce, nonce, buffer.Bytes(), nil)
return ciphertext, nil
}
|
