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
|
// Copyright 2020 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 subtle
import (
"fmt"
"github.com/tink-crypto/tink-go/v2/aead/aesgcm"
"github.com/tink-crypto/tink-go/v2/insecuresecretdataaccess"
"github.com/tink-crypto/tink-go/v2/secretdata"
"github.com/tink-crypto/tink-go/v2/tink"
)
const (
// AESGCMIVSize is the acceptable IV size defined by RFC 5116.
AESGCMIVSize = 12
// AESGCMTagSize is the acceptable tag size defined by RFC 5116.
AESGCMTagSize = 16
maxIntPlaintextSize = maxInt - AESGCMIVSize - AESGCMTagSize
)
// AESGCM is an implementation of the [tink.AEAD] interface.
//
// This primitive adds no prefix to the ciphertext.
type AESGCM struct {
aeadImpl tink.AEAD
}
// NewAESGCM returns an [*AESGCM] value from the given key.
//
// The key must be of length 16 or 32 bytes. IV and TAG sizes are fixed to 12
// and 16 bytes respectively.
func NewAESGCM(key []byte) (*AESGCM, error) {
opts := aesgcm.ParametersOpts{
KeySizeInBytes: len(key),
IVSizeInBytes: AESGCMIVSize,
TagSizeInBytes: AESGCMTagSize,
Variant: aesgcm.VariantNoPrefix,
}
params, err := aesgcm.NewParameters(opts)
if err != nil {
return nil, fmt.Errorf("subtle.NewAESGCM: %v", err)
}
k, err := aesgcm.NewKey(secretdata.NewBytesFromData(key, insecuresecretdataaccess.Token{}), 0, params)
if err != nil {
return nil, fmt.Errorf("subtle.NewAESGCM: %v", err)
}
aead, err := aesgcm.NewAEAD(k)
if err != nil {
return nil, fmt.Errorf("subtle.NewAESGCM: %v", err)
}
return &AESGCM{aeadImpl: aead}, nil
}
// Encrypt encrypts the plaintext with the associated data.
func (a *AESGCM) Encrypt(plaintext, associatedData []byte) ([]byte, error) {
return a.aeadImpl.Encrypt(plaintext, associatedData)
}
// Decrypt decrypts the ciphertext with the associated data.
func (a *AESGCM) Decrypt(ciphertext, associatedData []byte) ([]byte, error) {
return a.aeadImpl.Decrypt(ciphertext, associatedData)
}
|
