1 // Copyright 2018 Google Inc. 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 #ifndef TINK_AEAD_XCHACHA20_POLY1305_KEY_MANAGER_H_ 17 #define TINK_AEAD_XCHACHA20_POLY1305_KEY_MANAGER_H_ 18 19 #include <stdint.h> 20 21 #include <memory> 22 #include <string> 23 24 #include "absl/memory/memory.h" 25 #include "absl/status/status.h" 26 #include "absl/strings/str_cat.h" 27 #include "tink/aead.h" 28 #include "tink/core/key_type_manager.h" 29 #include "tink/core/template_util.h" 30 #include "tink/input_stream.h" 31 #include "tink/subtle/random.h" 32 #include "tink/subtle/xchacha20_poly1305_boringssl.h" 33 #include "tink/util/constants.h" 34 #include "tink/util/input_stream_util.h" 35 #include "tink/util/secret_data.h" 36 #include "tink/util/status.h" 37 #include "tink/util/statusor.h" 38 #include "tink/util/validation.h" 39 #include "proto/tink.pb.h" 40 #include "proto/xchacha20_poly1305.pb.h" 41 42 namespace crypto { 43 namespace tink { 44 45 class XChaCha20Poly1305KeyManager 46 : public KeyTypeManager<google::crypto::tink::XChaCha20Poly1305Key, 47 google::crypto::tink::XChaCha20Poly1305KeyFormat, 48 List<Aead>> { 49 public: 50 class AeadFactory : public PrimitiveFactory<Aead> { Create(const google::crypto::tink::XChaCha20Poly1305Key & key)51 crypto::tink::util::StatusOr<std::unique_ptr<Aead>> Create( 52 const google::crypto::tink::XChaCha20Poly1305Key& key) const override { 53 return subtle::XChacha20Poly1305BoringSsl::New( 54 util::SecretDataFromStringView(key.key_value())); 55 } 56 }; 57 XChaCha20Poly1305KeyManager()58 XChaCha20Poly1305KeyManager() 59 : KeyTypeManager(absl::make_unique<AeadFactory>()) {} 60 get_version()61 uint32_t get_version() const override { return 0; } 62 key_material_type()63 google::crypto::tink::KeyData::KeyMaterialType key_material_type() 64 const override { 65 return google::crypto::tink::KeyData::SYMMETRIC; 66 } 67 get_key_type()68 const std::string& get_key_type() const override { return key_type_; } 69 ValidateKey(const google::crypto::tink::XChaCha20Poly1305Key & key)70 crypto::tink::util::Status ValidateKey( 71 const google::crypto::tink::XChaCha20Poly1305Key& key) const override { 72 crypto::tink::util::Status status = 73 ValidateVersion(key.version(), get_version()); 74 if (!status.ok()) return status; 75 uint32_t key_size = key.key_value().size(); 76 if (key.key_value().size() != kKeySizeInBytes) { 77 return crypto::tink::util::Status( 78 absl::StatusCode::kInvalidArgument, 79 absl::StrCat("Invalid XChaCha20Poly1305Key: key_value has ", key_size, 80 " bytes; supported size: ", kKeySizeInBytes, " bytes.")); 81 } 82 return crypto::tink::util::OkStatus(); 83 } 84 ValidateKeyFormat(const google::crypto::tink::XChaCha20Poly1305KeyFormat & key_format)85 crypto::tink::util::Status ValidateKeyFormat( 86 const google::crypto::tink::XChaCha20Poly1305KeyFormat& key_format) 87 const override { 88 return crypto::tink::util::OkStatus(); 89 } 90 91 crypto::tink::util::StatusOr<google::crypto::tink::XChaCha20Poly1305Key> CreateKey(const google::crypto::tink::XChaCha20Poly1305KeyFormat & key_format)92 CreateKey(const google::crypto::tink::XChaCha20Poly1305KeyFormat& key_format) 93 const override { 94 google::crypto::tink::XChaCha20Poly1305Key result; 95 result.set_version(get_version()); 96 result.set_key_value(subtle::Random::GetRandomBytes(kKeySizeInBytes)); 97 return result; 98 } 99 100 crypto::tink::util::StatusOr<google::crypto::tink::XChaCha20Poly1305Key> DeriveKey(const google::crypto::tink::XChaCha20Poly1305KeyFormat & key_format,InputStream * input_stream)101 DeriveKey(const google::crypto::tink::XChaCha20Poly1305KeyFormat& key_format, 102 InputStream* input_stream) const override { 103 crypto::tink::util::Status status = 104 ValidateVersion(key_format.version(), get_version()); 105 if (!status.ok()) return status; 106 107 crypto::tink::util::StatusOr<std::string> randomness = 108 ReadBytesFromStream(kKeySizeInBytes, input_stream); 109 if (!randomness.ok()) { 110 if (randomness.status().code() == absl::StatusCode::kOutOfRange) { 111 return crypto::tink::util::Status( 112 absl::StatusCode::kInvalidArgument, 113 "Could not get enough pseudorandomness from input stream"); 114 } 115 return randomness.status(); 116 } 117 google::crypto::tink::XChaCha20Poly1305Key key; 118 key.set_version(get_version()); 119 key.set_key_value(randomness.value()); 120 return key; 121 } 122 123 private: 124 const std::string key_type_ = 125 absl::StrCat(kTypeGoogleapisCom, 126 google::crypto::tink::XChaCha20Poly1305Key().GetTypeName()); 127 const int kKeySizeInBytes = 32; 128 }; 129 130 } // namespace tink 131 } // namespace crypto 132 133 #endif // TINK_AEAD_XCHACHA20_POLY1305_KEY_MANAGER_H_ 134