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
|
/*-
* Copyright 2019 Square Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"crypto"
"encoding/base64"
"flag"
"fmt"
"github.com/go-jose/go-jose/v4"
"github.com/go-jose/go-jose/v4/jose-util/generator"
)
func generate(args []string) error {
fs := flag.NewFlagSet("generate", flag.ExitOnError)
generateUseFlag := fs.String("use", "", "Desired public key usage (use header), one of [enc sig]")
generateAlgFlag := fs.String("alg", "", "Desired key pair algorithm (alg header)")
generateKeySizeFlag := fs.Int("size", 0, "Key size in bits (e.g. 2048 if generating an RSA key)")
generateKeyIdentFlag := fs.String("kid", "", "Optional Key ID (kid header, generate random kid if not set)")
fs.Parse(args)
var privKey crypto.PrivateKey
var pubKey crypto.PublicKey
var err error
switch *generateUseFlag {
case "sig":
pubKey, privKey, err = generator.NewSigningKey(jose.SignatureAlgorithm(*generateAlgFlag), *generateKeySizeFlag)
case "enc":
pubKey, privKey, err = generator.NewEncryptionKey(jose.KeyAlgorithm(*generateAlgFlag), *generateKeySizeFlag)
default:
// According to RFC 7517 section-8.2. This is unlikely to change in the
// near future. If it were, new values could be found in the registry under
// "JSON Web Key Use": https://www.iana.org/assignments/jose/jose.xhtml
return fmt.Errorf("invalid key use '%s'. Must be \"sig\" or \"enc\"", *generateUseFlag)
}
if err != nil {
return fmt.Errorf("unable to generate key: %w", err)
}
kid := *generateKeyIdentFlag
priv := jose.JSONWebKey{Key: privKey, KeyID: kid, Algorithm: *generateAlgFlag, Use: *generateUseFlag}
// Generate a canonical kid based on RFC 7638
if kid == "" {
thumb, err := priv.Thumbprint(crypto.SHA256)
if err != nil {
return fmt.Errorf("unable to compute thumbprint: %w", err)
}
kid = base64.URLEncoding.EncodeToString(thumb)
priv.KeyID = kid
}
// I'm not sure why we couldn't use `pub := priv.Public()` here as the private
// key should contain the public key. In case for some reason it doesn't,
// this builds a public JWK from scratch.
pub := jose.JSONWebKey{Key: pubKey, KeyID: kid, Algorithm: *generateAlgFlag, Use: *generateUseFlag}
if priv.IsPublic() || !pub.IsPublic() || !priv.Valid() || !pub.Valid() {
// This should never happen
panic("invalid keys were generated")
}
privJSON, err := priv.MarshalJSON()
if err != nil {
return fmt.Errorf("failed to marshal private key to JSON: %w", err)
}
pubJSON, err := pub.MarshalJSON()
if err != nil {
return fmt.Errorf("failed to marshal public key to JSON: %w", err)
}
name := fmt.Sprintf("jwk-%s-%s", *generateUseFlag, kid)
pubFile := fmt.Sprintf("%s-pub.json", name)
privFile := fmt.Sprintf("%s-priv.json", name)
err = writeNewFile(pubFile, pubJSON, 0444)
if err != nil {
return fmt.Errorf("error on write to file %s: %w", pubFile, err)
}
err = writeNewFile(privFile, privJSON, 0400)
if err != nil {
return fmt.Errorf("error on write to file %s: %w", privFile, err)
}
return nil
}
|
