1 // Copyright 2019 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_KEYDERIVATION_KEY_DERIVATION_KEY_TEMPLATES_H_ 18 #define TINK_KEYDERIVATION_KEY_DERIVATION_KEY_TEMPLATES_H_ 19 20 #include "tink/util/statusor.h" 21 #include "proto/tink.pb.h" 22 23 namespace crypto { 24 namespace tink { 25 26 /////////////////////////////////////////////////////////////////////////////// 27 // Methods to generate KeyTemplates for key derivation. 28 class KeyDerivationKeyTemplates { 29 public: 30 // Creates a key template for key derivation that uses a PRF to derive a key 31 // that adheres to `derived_key_template`. The following must be true: 32 // (1) `prf_key_template` is a PRF key template, i.e. 33 // `keyset_handle->GetPrimitive<StreamingPrf>()` works. 34 // (2) `derived_key_template` describes a key type that supports derivation. 35 // 36 // The output prefix type of the derived key will match the output prefix type 37 // of `derived_key_template`. 38 // 39 // This function verifies the newly created key template by creating a 40 // KeysetDeriver primitive from it. This requires both the `prf_key_template` 41 // and `derived_key_template` key types to be in the registry. It also 42 // attempts to derive a key, returning an error on failure. 43 static util::StatusOr<google::crypto::tink::KeyTemplate> 44 CreatePrfBasedKeyTemplate( 45 const google::crypto::tink::KeyTemplate& prf_key_template, 46 const google::crypto::tink::KeyTemplate& derived_key_template); 47 }; 48 49 } // namespace tink 50 } // namespace crypto 51 52 #endif // TINK_KEYDERIVATION_KEY_DERIVATION_KEY_TEMPLATES_H_ 53