| // Copyright 2019 Google Inc. |
| // |
| // 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 |
| // |
| // http://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 TINK_SUBTLE_STREAMING_AEAD_ENCRYPTING_STREAM_H_ |
| #define TINK_SUBTLE_STREAMING_AEAD_ENCRYPTING_STREAM_H_ |
| |
| #include <memory> |
| #include <vector> |
| |
| #include "tink/output_stream.h" |
| #include "tink/subtle/stream_segment_encrypter.h" |
| #include "tink/util/statusor.h" |
| |
| namespace crypto { |
| namespace tink { |
| namespace subtle { |
| |
| class NonceBasedStreamingAead; |
| |
| class StreamingAeadEncryptingStream : public OutputStream { |
| public: |
| // A factory that produces encrypting streams. |
| // The returned stream is a wrapper around 'ciphertext_destination', |
| // such that any bytes written via the wrapper are streaming AEAD-encrypted |
| // via 'nonce_based_streaming_aead' using 'associated_data' as |
| // associated authenticated data. |
| static |
| crypto::tink::util::StatusOr<std::unique_ptr<crypto::tink::OutputStream>> |
| New(std::unique_ptr<StreamSegmentEncrypter> segment_encrypter, |
| std::unique_ptr<crypto::tink::OutputStream> ciphertext_destination); |
| |
| // ----------------------- |
| // Methods of OutputStream-interface implemented by this class. |
| crypto::tink::util::StatusOr<int> Next(void** data) override; |
| void BackUp(int count) override; |
| crypto::tink::util::Status Close() override; |
| int64_t Position() const override; |
| |
| private: |
| StreamingAeadEncryptingStream() {} |
| std::unique_ptr<StreamSegmentEncrypter> segment_encrypter_; |
| std::unique_ptr<crypto::tink::OutputStream> ct_destination_; |
| std::vector<uint8_t> pt_buffer_; // plaintext buffer |
| std::vector<uint8_t> ct_buffer_; // ciphertext buffer |
| std::vector<uint8_t> pt_to_encrypt_; // plaintext to be encrypted |
| int64_t position_; // number of plaintext bytes written to this stream |
| crypto::tink::util::Status status_; // status of the stream |
| |
| // Counters that describe the state of the data in pt_buffer_. |
| int count_backedup_; // # bytes in pt_buffer_ that were backed up |
| int pt_buffer_offset_; // offset at which *data starts in pt_buffer_ |
| |
| // Flag that indicates user obtained a buffer to write data of |
| // the first segment. |
| // If true, Next() was not called yet, which implies that neither |
| // header has been written to ct_destination_, nor the user had |
| // a chance to write any data to this stream. |
| bool is_first_segment_; |
| }; |
| |
| } // namespace subtle |
| } // namespace tink |
| } // namespace crypto |
| |
| #endif // TINK_SUBTLE_STREAMING_AEAD_ENCRYPTING_STREAM_H_ |