mirror of https://git.matrix.org/git/olm.git
129 lines
3.3 KiB
C++
129 lines
3.3 KiB
C++
/* Copyright 2015 OpenMarket Ltd
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "axolotl/crypto.hh"
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#include "axolotl/list.hh"
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namespace axolotl {
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typedef std::uint8_t SharedKey[32];
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struct ChainKey {
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std::uint32_t index;
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SharedKey key;
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};
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struct MessageKey {
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std::uint32_t index;
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Aes256Key cipher_key;
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SharedKey mac_key;
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Aes256Iv iv;
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};
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struct SenderChain {
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Curve25519KeyPair ratchet_key;
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ChainKey chain_key;
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};
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struct ReceiverChain {
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Curve25519PublicKey ratchet_key;
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ChainKey chain_key;
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};
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struct SkippedMessageKey {
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Curve25519PublicKey ratchet_key;
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MessageKey message_key;
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};
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enum struct ErrorCode {
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SUCCESS = 0, /*!< There wasn't an error */
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NOT_ENOUGH_RANDOM = 1, /*!< Not enough entropy was supplied */
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OUTPUT_BUFFER_TOO_SMALL = 2, /*!< Supplied output buffer is too small */
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BAD_MESSAGE_VERSION = 3, /*!< The message version is unsupported */
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BAD_MESSAGE_FORMAT = 4, /*!< The message couldn't be decoded */
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BAD_MESSAGE_MAC = 5, /*!< The message couldn't be decrypted */
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};
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static std::size_t const MAX_RECEIVER_CHAINS = 5;
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static std::size_t const MAX_SKIPPED_MESSAGE_KEYS = 40;
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struct KdfInfo {
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std::uint8_t const * root_info;
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std::size_t root_info_length;
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std::uint8_t const * ratchet_info;
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std::size_t ratchet_info_length;
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std::uint8_t const * message_info;
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std::size_t message_info_length;
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};
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struct Session {
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Session(
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KdfInfo const & kdf_info
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);
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/** A pair of string to feed into the KDF identifing the application */
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KdfInfo kdf_info;
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/** The last error that happened encypting or decrypting a message */
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ErrorCode last_error;
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SharedKey root_key;
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List<SenderChain, 1> sender_chain;
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List<ReceiverChain, MAX_RECEIVER_CHAINS> receiver_chains;
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List<SkippedMessageKey, MAX_SKIPPED_MESSAGE_KEYS> skipped_message_keys;
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void initialise_as_bob(
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std::uint8_t const * shared_secret, std::size_t shared_secret_length,
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Curve25519PublicKey const & their_ratchet_key
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);
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void initialise_as_alice(
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std::uint8_t const * shared_secret, std::size_t shared_secret_length,
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Curve25519KeyPair const & our_ratchet_key
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);
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std::size_t encrypt_max_output_length(
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std::size_t plaintext_length
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);
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std::size_t encrypt_random_length();
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std::size_t encrypt(
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std::uint8_t const * plaintext, std::size_t plaintext_length,
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std::uint8_t const * random, std::size_t random_length,
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std::uint8_t * output, std::size_t max_output_length
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);
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std::size_t decrypt_max_plaintext_length(
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std::size_t input_length
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);
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std::size_t decrypt(
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t * plaintext, std::size_t max_plaintext_length
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);
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};
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} // namespace axololt
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