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
|
// Copyright 2018 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 aesgcmsiv
import (
"fmt"
"google.golang.org/protobuf/proto"
"github.com/tink-crypto/tink-go/v2/aead/subtle"
"github.com/tink-crypto/tink-go/v2/core/registry"
"github.com/tink-crypto/tink-go/v2/internal/protoserialization"
"github.com/tink-crypto/tink-go/v2/keyset"
"github.com/tink-crypto/tink-go/v2/subtle/random"
gcmsivpb "github.com/tink-crypto/tink-go/v2/proto/aes_gcm_siv_go_proto"
tinkpb "github.com/tink-crypto/tink-go/v2/proto/tink_go_proto"
)
// aesGCMSIVKeyManager implements [registry.KeyManager] for AES-GCM-SIV.
//
// It generates new AESGCMSIVKey keys and can create [tink.AEAD] primitives
// that implement AES-GCM-SIV.
type aesGCMSIVKeyManager struct{}
var _ registry.KeyManager = (*aesGCMSIVKeyManager)(nil)
// Primitive creates an [tink.AEAD] primitive from a serialized
// [gcmsivpb.AesGcmSivKey].
func (km *aesGCMSIVKeyManager) Primitive(serializedKey []byte) (any, error) {
keySerialization, err := protoserialization.NewKeySerialization(&tinkpb.KeyData{
TypeUrl: typeURL,
Value: serializedKey,
KeyMaterialType: tinkpb.KeyData_SYMMETRIC,
}, tinkpb.OutputPrefixType_RAW, 0)
if err != nil {
return nil, err
}
key, err := protoserialization.ParseKey(keySerialization)
if err != nil {
return nil, err
}
aesGCMSIVKey, ok := key.(*Key)
if !ok {
return nil, fmt.Errorf("aes_gcm_siv_key_manager: invalid key type: got %T, want %T", key, (*Key)(nil))
}
ret, err := newAEAD(aesGCMSIVKey)
if err != nil {
return nil, fmt.Errorf("aes_gcm_siv_key_manager: %v", err)
}
return ret, nil
}
// NewKey creates a new [gcmsivpb.AesGcmSivKey] from the given serialized
// [gcmsivpb.AesGcmSivKeyFormat].
func (km *aesGCMSIVKeyManager) NewKey(serializedKeyFormat []byte) (proto.Message, error) {
if len(serializedKeyFormat) == 0 {
return nil, fmt.Errorf("aes_gcm_siv_key_manager: invalid key format")
}
keyFormat := new(gcmsivpb.AesGcmSivKeyFormat)
if err := proto.Unmarshal(serializedKeyFormat, keyFormat); err != nil {
return nil, fmt.Errorf("aes_gcm_siv_key_manager: invalid key format")
}
if err := km.validateKeyFormat(keyFormat); err != nil {
return nil, fmt.Errorf("aes_gcm_siv_key_manager: invalid key format: %s", err)
}
keyValue := random.GetRandomBytes(keyFormat.KeySize)
return &gcmsivpb.AesGcmSivKey{
Version: 0,
KeyValue: keyValue,
}, nil
}
// NewKeyData creates a new [tinkpb.KeyData] from the given serialized
// [gcmsivpb.AesGcmSivKeyFormat].
//
// It should be used solely by the key management API.
func (km *aesGCMSIVKeyManager) 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, err
}
return &tinkpb.KeyData{
TypeUrl: typeURL,
Value: serializedKey,
KeyMaterialType: tinkpb.KeyData_SYMMETRIC,
}, nil
}
// DoesSupport indicates if this key manager supports the given key type.
func (km *aesGCMSIVKeyManager) DoesSupport(typeURL string) bool { return km.TypeURL() == typeURL }
// TypeURL returns the key type of keys managed by this key manager.
func (km *aesGCMSIVKeyManager) TypeURL() string { return typeURL }
func (km *aesGCMSIVKeyManager) validateKey(key *gcmsivpb.AesGcmSivKey) error {
err := keyset.ValidateKeyVersion(key.Version, 0)
if err != nil {
return fmt.Errorf("aes_gcm_siv_key_manager: %s", err)
}
keySize := uint32(len(key.KeyValue))
if err := subtle.ValidateAESKeySize(keySize); err != nil {
return fmt.Errorf("aes_gcm_siv_key_manager: %s", err)
}
return nil
}
func (km *aesGCMSIVKeyManager) validateKeyFormat(format *gcmsivpb.AesGcmSivKeyFormat) error {
if err := subtle.ValidateAESKeySize(format.KeySize); err != nil {
return fmt.Errorf("aes_gcm_siv_key_manager: %s", err)
}
return nil
}
|
