1 // Copyright 2021 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/experimental/pqcrypto/signature/subtle/falcon_sign.h"
18
19 #include <memory>
20 #include <string>
21 #include <utility>
22
23 #include "absl/memory/memory.h"
24 #include "absl/status/status.h"
25 #include "absl/strings/str_format.h"
26 #include "tink/experimental/pqcrypto/signature/subtle/falcon_subtle_utils.h"
27 #include "tink/util/secret_data.h"
28 #include "tink/util/statusor.h"
29
30 extern "C" {
31 #include "third_party/pqclean/crypto_sign/falcon-1024/api.h"
32 #include "third_party/pqclean/crypto_sign/falcon-512/api.h"
33 }
34
35 namespace crypto {
36 namespace tink {
37 namespace subtle {
38
39 // static
New(const FalconPrivateKeyPqclean & key)40 util::StatusOr<std::unique_ptr<PublicKeySign>> FalconSign::New(
41 const FalconPrivateKeyPqclean& key) {
42 auto status = internal::CheckFipsCompatibility<FalconSign>();
43 if (!status.ok()) return status;
44
45 return {absl::WrapUnique(new FalconSign(key))};
46 }
47
Sign(absl::string_view data) const48 util::StatusOr<std::string> FalconSign::Sign(absl::string_view data) const {
49 size_t sig_length;
50 int32_t key_size = private_key_.GetKey().size();
51 std::string signature;
52 int result = 1;
53
54 switch (key_size) {
55 case kFalcon512PrivateKeySize: {
56 signature.resize(PQCLEAN_FALCON512_CRYPTO_BYTES, '0');
57 result = PQCLEAN_FALCON512_crypto_sign_signature(
58 reinterpret_cast<uint8_t *>(signature.data()), &sig_length,
59 reinterpret_cast<const uint8_t *>(data.data()), data.size(),
60 reinterpret_cast<const uint8_t *>(private_key_.GetKey().data()));
61 if (sig_length > PQCLEAN_FALCON512_CRYPTO_BYTES) {
62 result = -1;
63 }
64 break;
65 }
66 case kFalcon1024PrivateKeySize: {
67 signature.resize(PQCLEAN_FALCON1024_CRYPTO_BYTES, '0');
68 result = PQCLEAN_FALCON1024_crypto_sign_signature(
69 reinterpret_cast<uint8_t *>(signature.data()), &sig_length,
70 reinterpret_cast<const uint8_t *>(data.data()), data.size(),
71 reinterpret_cast<const uint8_t *>(private_key_.GetKey().data()));
72 if (sig_length > PQCLEAN_FALCON1024_CRYPTO_BYTES) {
73 result = -1;
74 }
75 break;
76 }
77 default:
78 return util::Status(absl::StatusCode::kInvalidArgument,
79 "Invalid keysize.");
80 }
81
82 if (result != 0) {
83 return util::Status(absl::StatusCode::kInternal, "Signing failed.");
84 }
85
86 signature.resize(sig_length);
87 return signature;
88 }
89
90 } // namespace subtle
91 } // namespace tink
92 } // namespace crypto
93