-
Notifications
You must be signed in to change notification settings - Fork 0
/
decoder.go
94 lines (73 loc) · 2.39 KB
/
decoder.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
package scrypt
import (
"encoding/base64"
"fmt"
"github.com/go-crypt/crypt/algorithm"
"github.com/go-crypt/crypt/internal/encoding"
)
// RegisterDecoder the decoder with the algorithm.DecoderRegister.
func RegisterDecoder(r algorithm.DecoderRegister) (err error) {
if err = r.RegisterDecodeFunc(AlgName, Decode); err != nil {
return err
}
return nil
}
// Decode the encoded digest into a algorithm.Digest.
func Decode(encodedDigest string) (digest algorithm.Digest, err error) {
var (
parts []string
)
if parts, err = decoderParts(encodedDigest); err != nil {
return nil, fmt.Errorf(algorithm.ErrFmtDigestDecode, AlgName, err)
}
if digest, err = decode(parts); err != nil {
return nil, fmt.Errorf(algorithm.ErrFmtDigestDecode, AlgName, err)
}
return digest, nil
}
func decoderParts(encodedDigest string) (parts []string, err error) {
parts = encoding.Split(encodedDigest, -1)
if len(parts) != 5 {
return nil, algorithm.ErrEncodedHashInvalidFormat
}
if parts[1] != AlgName {
return nil, fmt.Errorf("%w: identifier '%s' is not an encoded %s digest", algorithm.ErrEncodedHashInvalidIdentifier, parts[1], AlgName)
}
return parts[2:], nil
}
func decode(parts []string) (digest algorithm.Digest, err error) {
decoded := &Digest{
ln: IterationsDefault,
r: BlockSizeDefault,
p: ParallelismDefault,
}
var params []encoding.Parameter
if params, err = encoding.DecodeParameterStr(parts[0]); err != nil {
return nil, err
}
for _, param := range params {
switch param.Key {
case oLN:
decoded.ln, err = param.Int()
case oR:
decoded.r, err = param.Int()
case oP:
decoded.p, err = param.Int()
default:
return nil, fmt.Errorf("%w: option '%s' with value '%s' is unknown", algorithm.ErrEncodedHashInvalidOptionKey, param.Key, param.Value)
}
if err != nil {
return nil, fmt.Errorf("%w: option '%s' has invalid value '%s': %v", algorithm.ErrEncodedHashInvalidOptionValue, param.Key, param.Value, err)
}
}
if decoded.salt, err = base64.RawStdEncoding.DecodeString(parts[1]); err != nil {
return nil, fmt.Errorf("%w: %v", algorithm.ErrEncodedHashSaltEncoding, err)
}
if decoded.key, err = base64.RawStdEncoding.DecodeString(parts[2]); err != nil {
return nil, fmt.Errorf("%w: %v", algorithm.ErrEncodedHashKeyEncoding, err)
}
if len(decoded.key) == 0 {
return nil, fmt.Errorf("%w: key has 0 bytes", algorithm.ErrEncodedHashKeyEncoding)
}
return decoded, nil
}