1 // Copyright 2023 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
17 #include "tink/signature/ed25519_public_key.h"
18
19 #include <string>
20
21 #include "absl/base/attributes.h"
22 #include "absl/strings/escaping.h"
23 #include "absl/types/optional.h"
24 #include "tink/partial_key_access_token.h"
25 #include "tink/signature/ed25519_parameters.h"
26 #include "tink/subtle/subtle_util.h"
27 #include "tink/util/status.h"
28 #include "tink/util/statusor.h"
29
30 namespace crypto {
31 namespace tink {
32 namespace {
33
ComputeOutputPrefix(const Ed25519Parameters & parameters,absl::optional<int> id_requirement)34 util::StatusOr<std::string> ComputeOutputPrefix(
35 const Ed25519Parameters& parameters, absl::optional<int> id_requirement) {
36 switch (parameters.GetVariant()) {
37 case Ed25519Parameters::Variant::kNoPrefix:
38 return std::string(""); // Empty prefix.
39 case Ed25519Parameters::Variant::kLegacy:
40 ABSL_FALLTHROUGH_INTENDED;
41 case Ed25519Parameters::Variant::kCrunchy:
42 if (!id_requirement.has_value()) {
43 return util::Status(
44 absl::StatusCode::kInvalidArgument,
45 "ID requirement must have value with kCrunchy or kLegacy");
46 }
47 return absl::StrCat(absl::HexStringToBytes("00"),
48 subtle::BigEndian32(*id_requirement));
49 case Ed25519Parameters::Variant::kTink:
50 if (!id_requirement.has_value()) {
51 return util::Status(absl::StatusCode::kInvalidArgument,
52 "ID requirement must have value with kTink");
53 }
54 return absl::StrCat(absl::HexStringToBytes("01"),
55 subtle::BigEndian32(*id_requirement));
56 default:
57 return util::Status(
58 absl::StatusCode::kInvalidArgument,
59 absl::StrCat("Invalid variant: ", parameters.GetVariant()));
60 }
61 }
62
63 } // namespace
64
Create(const Ed25519Parameters & parameters,absl::string_view public_key_bytes,absl::optional<int> id_requirement,PartialKeyAccessToken token)65 util::StatusOr<Ed25519PublicKey> Ed25519PublicKey::Create(
66 const Ed25519Parameters& parameters, absl::string_view public_key_bytes,
67 absl::optional<int> id_requirement, PartialKeyAccessToken token) {
68 if (parameters.HasIdRequirement() && !id_requirement.has_value()) {
69 return util::Status(
70 absl::StatusCode::kInvalidArgument,
71 "Cannot create key without ID requirement with parameters with ID "
72 "requirement");
73 }
74 if (!parameters.HasIdRequirement() && id_requirement.has_value()) {
75 return util::Status(
76 absl::StatusCode::kInvalidArgument,
77 "Cannot create key with ID requirement with parameters without ID "
78 "requirement");
79 }
80 if (public_key_bytes.size() != 32) {
81 return util::Status(absl::StatusCode::kInvalidArgument,
82 "Ed25519 public key length must be 32 bytes.");
83 }
84 util::StatusOr<std::string> output_prefix =
85 ComputeOutputPrefix(parameters, id_requirement);
86 if (!output_prefix.ok()) {
87 return output_prefix.status();
88 }
89 return Ed25519PublicKey(parameters, public_key_bytes, id_requirement,
90 *output_prefix);
91 }
92
operator ==(const Key & other) const93 bool Ed25519PublicKey::operator==(const Key& other) const {
94 const Ed25519PublicKey* that = dynamic_cast<const Ed25519PublicKey*>(&other);
95 if (that == nullptr) {
96 return false;
97 }
98 if (GetParameters() != that->GetParameters()) {
99 return false;
100 }
101 if (id_requirement_ != that->id_requirement_) {
102 return false;
103 }
104 return public_key_bytes_ == that->public_key_bytes_;
105 }
106
107 } // namespace tink
108 } // namespace crypto
109