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 #ifndef TINK_HYBRID_HYBRID_PRIVATE_KEY_H_ 18 #define TINK_HYBRID_HYBRID_PRIVATE_KEY_H_ 19 20 #include "absl/strings/string_view.h" 21 #include "tink/hybrid/hybrid_parameters.h" 22 #include "tink/hybrid/hybrid_public_key.h" 23 #include "tink/key.h" 24 #include "tink/private_key.h" 25 26 namespace crypto { 27 namespace tink { 28 29 // Represents the decryption function for a hybrid encryption primitive. 30 class HybridPrivateKey : public PrivateKey { 31 public: 32 const HybridPublicKey& GetPublicKey() const override = 0; 33 34 // Returns the bytes prefixed to every ciphertext generated by the 35 // corresponding public key. 36 // 37 // In order to make key rotation more efficient, Tink allows every hybrid 38 // private key to have an associated ciphertext output prefix. When decrypting 39 // a ciphertext, only keys with a matching prefix have to be tried. 40 // 41 // See https://developers.google.com/tink/wire-format#tink_output_prefix for 42 // more background information on Tink output prefixes. GetOutputPrefix()43 absl::string_view GetOutputPrefix() const { 44 return GetPublicKey().GetOutputPrefix(); 45 } 46 GetIdRequirement()47 absl::optional<int> GetIdRequirement() const override { 48 return GetPublicKey().GetIdRequirement(); 49 } 50 GetParameters()51 const HybridParameters& GetParameters() const override { 52 return GetPublicKey().GetParameters(); 53 } 54 55 bool operator==(const Key& other) const override = 0; 56 }; 57 58 } // namespace tink 59 } // namespace crypto 60 61 #endif // TINK_HYBRID_HYBRID_PRIVATE_KEY_H_ 62