xref: /aosp_15_r20/external/tink/go/signature/ecdsa_verifier_key_manager.go (revision e7b1675dde1b92d52ec075b0a92829627f2c52a5) 
1// Copyright 2018 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14//
15////////////////////////////////////////////////////////////////////////////////
16
17package signature
18
19import (
20	"fmt"
21
22	"google.golang.org/protobuf/proto"
23	"github.com/google/tink/go/keyset"
24	"github.com/google/tink/go/signature/subtle"
25	ecdsapb "github.com/google/tink/go/proto/ecdsa_go_proto"
26	tinkpb "github.com/google/tink/go/proto/tink_go_proto"
27)
28
29const (
30	ecdsaVerifierKeyVersion = 0
31	ecdsaVerifierTypeURL    = "type.googleapis.com/google.crypto.tink.EcdsaPublicKey"
32)
33
34// common errors
35var errInvalidECDSAVerifierKey = fmt.Errorf("ecdsa_verifier_key_manager: invalid key")
36var errECDSAVerifierNotImplemented = fmt.Errorf("ecdsa_verifier_key_manager: not implemented")
37
38// ecdsaVerifierKeyManager is an implementation of KeyManager interface.
39// It doesn't support key generation.
40type ecdsaVerifierKeyManager struct{}
41
42// Primitive creates an ECDSAVerifier subtle for the given serialized ECDSAPublicKey proto.
43func (km *ecdsaVerifierKeyManager) Primitive(serializedKey []byte) (interface{}, error) {
44	if len(serializedKey) == 0 {
45		return nil, errInvalidECDSAVerifierKey
46	}
47	key := new(ecdsapb.EcdsaPublicKey)
48	if err := proto.Unmarshal(serializedKey, key); err != nil {
49		return nil, errInvalidECDSAVerifierKey
50	}
51	if err := km.validateKey(key); err != nil {
52		return nil, fmt.Errorf("ecdsa_verifier_key_manager: %s", err)
53	}
54	hash, curve, encoding := getECDSAParamNames(key.Params)
55	ret, err := subtle.NewECDSAVerifier(hash, curve, encoding, key.X, key.Y)
56	if err != nil {
57		return nil, fmt.Errorf("ecdsa_verifier_key_manager: invalid key: %s", err)
58	}
59	return ret, nil
60}
61
62// NewKey is not implemented.
63func (km *ecdsaVerifierKeyManager) NewKey(serializedKeyFormat []byte) (proto.Message, error) {
64	return nil, errECDSAVerifierNotImplemented
65}
66
67// NewKeyData creates a new KeyData according to specification in  the given
68// serialized ECDSAKeyFormat. It should be used solely by the key management API.
69func (km *ecdsaVerifierKeyManager) NewKeyData(serializedKeyFormat []byte) (*tinkpb.KeyData, error) {
70	return nil, errECDSAVerifierNotImplemented
71}
72
73// DoesSupport indicates if this key manager supports the given key type.
74func (km *ecdsaVerifierKeyManager) DoesSupport(typeURL string) bool {
75	return typeURL == ecdsaVerifierTypeURL
76}
77
78// TypeURL returns the key type of keys managed by this key manager.
79func (km *ecdsaVerifierKeyManager) TypeURL() string {
80	return ecdsaVerifierTypeURL
81}
82
83// validateKey validates the given ECDSAPublicKey.
84func (km *ecdsaVerifierKeyManager) validateKey(key *ecdsapb.EcdsaPublicKey) error {
85	if err := keyset.ValidateKeyVersion(key.Version, ecdsaVerifierKeyVersion); err != nil {
86		return fmt.Errorf("ecdsa_verifier_key_manager: %s", err)
87	}
88	hash, curve, encoding := getECDSAParamNames(key.Params)
89	return subtle.ValidateECDSAParams(hash, curve, encoding)
90}
91