-
Notifications
You must be signed in to change notification settings - Fork 0
/
encoder.go
70 lines (64 loc) · 1.44 KB
/
encoder.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
package encoder
import (
"bytes"
"encoding/base64"
"github.com/niktheblak/passwordhash/pkg/hasher"
)
type Encoder struct {
Prefix []byte
Salt []byte
Hash []byte
Encoding *base64.Encoding
}
func (e *Encoder) Encode() ([]byte, error) {
if len(e.Salt) == 0 {
return nil, hasher.ErrInvalidSalt
}
if len(e.Hash) == 0 {
return nil, hasher.ErrHashTooShort
}
buf := new(bytes.Buffer)
buf.WriteByte(byte(len(e.Salt)))
buf.Write(e.Salt)
buf.Write(e.Hash)
if e.Encoding == nil {
return buf.Bytes(), nil
}
encBuf := new(bytes.Buffer)
if len(e.Prefix) > 0 {
encBuf.Write(e.Prefix)
}
enc := base64.NewEncoder(e.Encoding, encBuf)
if _, err := buf.WriteTo(enc); err != nil {
return nil, err
}
return encBuf.Bytes(), nil
}
type Decoder struct {
Prefix []byte
Encoding *base64.Encoding
}
func (d *Decoder) Decode(encodedHash []byte) (salt []byte, hash []byte, err error) {
if len(d.Prefix) > 0 && !bytes.HasPrefix(encodedHash, d.Prefix) {
err = hasher.ErrInvalidHashPrefix
return
}
decodedLen := d.Encoding.DecodedLen(len(encodedHash) - len(d.Prefix))
decoded := make([]byte, decodedLen)
n, err := d.Encoding.Decode(decoded, encodedHash[len(d.Prefix):])
if err != nil {
return
}
r := bytes.NewReader(decoded[:n])
saltLen, err := r.ReadByte()
if err != nil {
return
}
salt = make([]byte, int(saltLen))
if _, err = r.Read(salt); err != nil {
return
}
hash = make([]byte, r.Len())
_, err = r.Read(hash)
return
}