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
|
// Copyright 2022 Google LLC
//
// 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 rsassapkcs1
import (
"crypto/rand"
"crypto/rsa"
"errors"
"fmt"
"math/big"
"google.golang.org/protobuf/proto"
"github.com/tink-crypto/tink-go/v2/core/registry"
"github.com/tink-crypto/tink-go/v2/internal/internalapi"
"github.com/tink-crypto/tink-go/v2/internal/protoserialization"
"github.com/tink-crypto/tink-go/v2/internal/signature"
"github.com/tink-crypto/tink-go/v2/keyset"
commonpb "github.com/tink-crypto/tink-go/v2/proto/common_go_proto"
rsassapkcs1pb "github.com/tink-crypto/tink-go/v2/proto/rsa_ssa_pkcs1_go_proto"
tinkpb "github.com/tink-crypto/tink-go/v2/proto/tink_go_proto"
)
const (
signerKeyVersion = 0
signerTypeURL = "type.googleapis.com/google.crypto.tink.RsaSsaPkcs1PrivateKey"
)
var (
errInvalidSignKey = errors.New("rsassapkcs1_signer_key_manager: invalid key")
errInvalidSignKeyFormat = errors.New("rsassapkcs1_signer_key_manager: invalid key format")
)
type signerKeyManager struct{}
var _ registry.PrivateKeyManager = (*signerKeyManager)(nil)
func hashName(h commonpb.HashType) string { return commonpb.HashType_name[int32(h)] }
func (km *signerKeyManager) Primitive(serializedKey []byte) (any, error) {
keySerialization, err := protoserialization.NewKeySerialization(&tinkpb.KeyData{
TypeUrl: signerTypeURL,
Value: serializedKey,
KeyMaterialType: tinkpb.KeyData_ASYMMETRIC_PRIVATE,
}, tinkpb.OutputPrefixType_RAW, 0)
if err != nil {
return nil, err
}
key, err := protoserialization.ParseKey(keySerialization)
if err != nil {
return nil, err
}
signerKey, ok := key.(*PrivateKey)
if !ok {
return nil, fmt.Errorf("rsassapkcs1_signer_key_manager: invalid key type: got %T, want %T", key, (*PrivateKey)(nil))
}
return NewSigner(signerKey, internalapi.Token{})
}
func validatePrivateKey(privKey *rsassapkcs1pb.RsaSsaPkcs1PrivateKey) error {
if err := keyset.ValidateKeyVersion(privKey.GetVersion(), signerKeyVersion); err != nil {
return err
}
if len(privKey.GetD()) == 0 ||
len(privKey.GetPublicKey().GetN()) == 0 ||
len(privKey.GetPublicKey().GetE()) == 0 ||
len(privKey.GetP()) == 0 ||
len(privKey.GetQ()) == 0 ||
len(privKey.GetDp()) == 0 ||
len(privKey.GetDq()) == 0 ||
len(privKey.GetCrt()) == 0 {
return errInvalidSignKey
}
return validatePublicKey(privKey.GetPublicKey())
}
func (km *signerKeyManager) NewKey(serializedKeyFormat []byte) (proto.Message, error) {
if len(serializedKeyFormat) == 0 {
return nil, errInvalidSignKeyFormat
}
keyFormat := &rsassapkcs1pb.RsaSsaPkcs1KeyFormat{}
if err := proto.Unmarshal(serializedKeyFormat, keyFormat); err != nil {
return nil, err
}
if err := signature.ValidateRSAPublicKeyParams(keyFormat.GetParams().GetHashType(), int(keyFormat.GetModulusSizeInBits()), keyFormat.GetPublicExponent()); err != nil {
return nil, err
}
rsaKey, err := rsa.GenerateKey(rand.Reader, int(keyFormat.GetModulusSizeInBits()))
if err != nil {
return nil, fmt.Errorf("generating RSA key: %s", err)
}
pubKey := &rsassapkcs1pb.RsaSsaPkcs1PublicKey{
Version: signerKeyVersion,
Params: &rsassapkcs1pb.RsaSsaPkcs1Params{
HashType: keyFormat.GetParams().GetHashType(),
},
N: rsaKey.PublicKey.N.Bytes(),
E: big.NewInt(int64(rsaKey.PublicKey.E)).Bytes(),
}
return &rsassapkcs1pb.RsaSsaPkcs1PrivateKey{
Version: signerKeyVersion,
PublicKey: pubKey,
D: rsaKey.D.Bytes(),
P: rsaKey.Primes[0].Bytes(),
Q: rsaKey.Primes[1].Bytes(),
Dp: rsaKey.Precomputed.Dp.Bytes(),
Dq: rsaKey.Precomputed.Dq.Bytes(),
// In crypto/rsa `Qinv` is the "Chinese Remainder Theorem
// coefficient q^(-1) mod p". This corresponds with `Crt` in
// the Tink proto. This is unrelated to `CRTValues`, which
// contains values specifically for additional primes, which
// are not supported by Tink.
Crt: rsaKey.Precomputed.Qinv.Bytes(),
}, nil
}
func (km *signerKeyManager) NewKeyData(serializedKeyFormat []byte) (*tinkpb.KeyData, error) {
key, err := km.NewKey(serializedKeyFormat)
if err != nil {
return nil, err
}
serializedKey, err := proto.Marshal(key)
if err != nil {
return nil, errInvalidSignKeyFormat
}
return &tinkpb.KeyData{
TypeUrl: signerTypeURL,
Value: serializedKey,
KeyMaterialType: tinkpb.KeyData_ASYMMETRIC_PRIVATE,
}, nil
}
// PublicKeyData extracts the public key data from the private key.
func (km *signerKeyManager) PublicKeyData(serializedPrivKey []byte) (*tinkpb.KeyData, error) {
privKey := &rsassapkcs1pb.RsaSsaPkcs1PrivateKey{}
if err := proto.Unmarshal(serializedPrivKey, privKey); err != nil {
return nil, err
}
if err := validatePrivateKey(privKey); err != nil {
return nil, err
}
serializedPubKey, err := proto.Marshal(privKey.GetPublicKey())
if err != nil {
return nil, err
}
return &tinkpb.KeyData{
TypeUrl: verifierTypeURL,
Value: serializedPubKey,
KeyMaterialType: tinkpb.KeyData_ASYMMETRIC_PUBLIC,
}, nil
}
// DoesSupport indicates if this key manager supports the given key type.
func (km *signerKeyManager) DoesSupport(typeURL string) bool { return typeURL == signerTypeURL }
// TypeURL returns the key type of keys managed by this key manager.
func (km *signerKeyManager) TypeURL() string { return signerTypeURL }
|
