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
|
// Copyright 2025 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 aesgcmhkdf
import (
"fmt"
"github.com/tink-crypto/tink-go/v2/insecuresecretdataaccess"
"github.com/tink-crypto/tink-go/v2/internal/aead"
"github.com/tink-crypto/tink-go/v2/key"
"github.com/tink-crypto/tink-go/v2/secretdata"
"github.com/tink-crypto/tink-go/v2/streamingaead/subtle"
)
// Key represents an AES-GCM-HKDF streaming AEAD key.
type Key struct {
keyBytes secretdata.Bytes
parameters *Parameters
}
var _ key.Key = (*Key)(nil)
// NewKey creates a new AES-GCM-HKDF key with the given key material and parameters.
//
// It returns an error if the parameters have an ID requirement.
func NewKey(parameters *Parameters, keyBytes secretdata.Bytes) (*Key, error) {
// Make sure the parameters object is neither nil nor empty.
if parameters == nil || parameters.KeySizeInBytes() == 0 {
return nil, fmt.Errorf("aesgcmhkdf.NewKey: invalid input parameters")
}
if keyBytes.Len() != int(parameters.KeySizeInBytes()) {
return nil, fmt.Errorf("aesgcmhkdf.NewKey: key length = %v, want %v", keyBytes.Len(), parameters.KeySizeInBytes())
}
return &Key{
keyBytes: keyBytes,
parameters: parameters,
}, nil
}
// KeyBytes returns the key material.
func (k *Key) KeyBytes() secretdata.Bytes { return k.keyBytes }
// Parameters returns the parameters of this key.
func (k *Key) Parameters() key.Parameters { return k.parameters }
// IDRequirement always returns (0, false), as ID requirements are not supported.
func (k *Key) IDRequirement() (uint32, bool) { return 0, false }
// Equal returns whether this key object is equal to other.
func (k *Key) Equal(other key.Key) bool {
that, ok := other.(*Key)
return ok &&
k.parameters.Equal(that.parameters) &&
k.keyBytes.Equal(that.keyBytes)
}
func primitiveConstructor(k key.Key) (any, error) {
that, ok := k.(*Key)
if !ok {
return nil, fmt.Errorf("key is of type %T, want %T", k, (*Key)(nil))
}
if err := aead.ValidateAESKeySize(uint32(that.keyBytes.Len())); err != nil {
return nil, fmt.Errorf("invalid key size: %v", err)
}
params := k.Parameters().(*Parameters)
return subtle.NewAESGCMHKDF(
that.keyBytes.Data(insecuresecretdataaccess.Token{}),
params.HKDFHashType().String(),
int(params.DerivedKeySizeInBytes()),
int(params.SegmentSizeInBytes()),
0, // no first segment offset
)
}
func createKey(p key.Parameters, idRequirement uint32) (key.Key, error) {
aesGCMHKDFParams, ok := p.(*Parameters)
if !ok {
return nil, fmt.Errorf("parameters is not a aesctrhmac.Parameters")
}
if idRequirement != 0 {
return nil, fmt.Errorf("ID requirements are not supported")
}
if err := aead.ValidateAESKeySize(uint32(aesGCMHKDFParams.KeySizeInBytes())); err != nil {
return nil, fmt.Errorf("invalid key size: %v", err)
}
keyBytes, err := secretdata.NewBytesFromRand(uint32(aesGCMHKDFParams.KeySizeInBytes()))
if err != nil {
return nil, fmt.Errorf("failed to generate random key material: %v", err)
}
return NewKey(aesGCMHKDFParams, keyBytes)
}
|
