| // Copyright 2020 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef THIRD_PARTY_PRIVATE_MEMBERSHIP_SRC_INTERNAL_AES_CTR_256_WITH_FIXED_IV_H_ |
| #define THIRD_PARTY_PRIVATE_MEMBERSHIP_SRC_INTERNAL_AES_CTR_256_WITH_FIXED_IV_H_ |
| |
| #include <memory> |
| #include <string> |
| |
| #include "third_party/private_membership/base/private_membership_export.h" |
| #include "absl/strings/string_view.h" |
| #include <openssl/evp.h> |
| #include "third_party/shell-encryption/src/statusor.h" |
| |
| namespace private_membership { |
| |
| // Wrapper around OpenSSL AES-CTR with 256 bit keys and a fixed IV. As a result, |
| // the encryptions will be deterministic (two encryptions of the a message under |
| // the same key results in the same two ciphertexts). |
| // |
| // Security: This cipher does not provide probabilistic encryption or |
| // authentication of the message. This should only be used in the scenario where |
| // each key will encrypt at most one message. |
| class PRIVATE_MEMBERSHIP_EXPORT AesCtr256WithFixedIV { |
| public: |
| // Create a cipher with the input key. |
| // |
| // Returns INVALID_ARGUMENT if key is an invalid size. |
| static ::rlwe::StatusOr<std::unique_ptr<AesCtr256WithFixedIV>> Create( |
| absl::string_view key); |
| |
| // Encrypts the plaintext. |
| // |
| // Returns INTERNAL on internal cryptographic errors. |
| ::rlwe::StatusOr<std::string> Encrypt(absl::string_view plaintext) const; |
| |
| // Decrypts the ciphertext. |
| // |
| // Returns INTERNAL on internal cryptographic errors. |
| ::rlwe::StatusOr<std::string> Decrypt(absl::string_view ciphertext) const; |
| |
| // The key size in bytes. |
| static constexpr uint8_t kKeySize = 32; |
| |
| private: |
| explicit AesCtr256WithFixedIV(absl::string_view key); |
| |
| static constexpr uint8_t kIVSize = 16; |
| |
| const std::string key_; |
| const std::string iv_; |
| }; |
| |
| } // namespace private_membership |
| |
| #endif // THIRD_PARTY_PRIVATE_MEMBERSHIP_SRC_INTERNAL_AES_CTR_256_WITH_FIXED_IV_H_ |