1 // Copyright 2020 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 #ifndef TINK_AEAD_CORD_AEAD_H_ 17 #define TINK_AEAD_CORD_AEAD_H_ 18 19 #include "absl/strings/cord.h" 20 #include "tink/util/statusor.h" 21 22 namespace crypto { 23 namespace tink { 24 25 /////////////////////////////////////////////////////////////////////////////// 26 // The interface for authenticated encryption with associated data. 27 // Implementations of this interface are secure against adaptive 28 // chosen ciphertext attacks. Encryption with associated data ensures 29 // authenticity and integrity of that data, but not its secrecy. 30 // (see RFC 5116, https://tools.ietf.org/html/rfc5116) 31 // 32 // Implementations are expected to be thread safe. 33 class CordAead { 34 public: 35 // Encrypts 'plaintext' with 'associated_data' as associated data, 36 // and returns the resulting ciphertext. 37 // The ciphertext allows for checking authenticity and integrity 38 // of the associated data, but does not guarantee its secrecy. 39 // The ciphertext is returned as a Cord and protects the secrecy, authenticity 40 // and integrity of the plaintext. 41 // An implementation of this interface must ensure that the Cord-structure 42 // of the returned ciphertext gives no information about the Cord-structure 43 // of the given plaintext. 44 virtual crypto::tink::util::StatusOr<absl::Cord> Encrypt( 45 absl::Cord plaintext, absl::Cord associated_data) const = 0; 46 47 // Decrypts 'ciphertext' with 'associated_data' as associated data, 48 // and returns the resulting plaintext. 49 // The decryption verifies the authenticity and integrity 50 // of the associated data, but there are no guarantees wrt. secrecy 51 // of that data. 52 // The plaintext is returned as a Cord. The structure of the Cord 53 // might differ from the original plaintext Cord, but the content will be the 54 // same. 55 virtual crypto::tink::util::StatusOr<absl::Cord> Decrypt( 56 absl::Cord ciphertext, 57 absl::Cord associated_data) const = 0; 58 59 virtual ~CordAead() = default; 60 }; 61 62 } // namespace tink 63 } // namespace crypto 64 65 #endif // TINK_AEAD_CORD_AEAD_H_ 66