mirror of https://git.matrix.org/git/olm.git
129 lines
4.0 KiB
C++
129 lines
4.0 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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#ifndef AXOLOTL_CIPHER_HH_
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#define AXOLOTL_CIPHER_HH_
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#include <cstdint>
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#include <cstddef>
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namespace axolotl {
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class Cipher {
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public:
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virtual ~Cipher();
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/**
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* Returns the length of the message authentication code that will be
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* appended to the output.
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*/
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virtual std::size_t mac_length() const = 0;
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/**
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* Returns the length of cipher-text for a given length of plain-text.
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*/
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virtual std::size_t encrypt_ciphertext_length(
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std::size_t plaintext_length
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) const = 0;
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/*
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* Encrypts the plain-text into the output buffer and authenticates the
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* contents of the output buffer covering both cipher-text and any other
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* associated data in the output buffer.
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*
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* |---------------------------------------output_length-->|
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* output |--ciphertext_length-->| |---mac_length-->|
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* ciphertext
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*
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* Returns std::size_t(-1) if the length of the cipher-text or the output
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* buffer is too small. Otherwise returns the length of the output buffer.
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*/
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virtual std::size_t encrypt(
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std::uint8_t const * key, std::size_t key_length,
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std::uint8_t const * plaintext, std::size_t plaintext_length,
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std::uint8_t * ciphertext, std::size_t ciphertext_length,
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std::uint8_t * output, std::size_t output_length
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) const = 0;
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/**
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* Returns the maximum length of plain-text that a given length of
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* cipher-text can contain.
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*/
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virtual std::size_t decrypt_max_plaintext_length(
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std::size_t ciphertext_length
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) const = 0;
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/**
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* Authenticates the input and decrypts the cipher-text into the plain-text
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* buffer.
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*
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* |----------------------------------------input_length-->|
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* input |--ciphertext_length-->| |---mac_length-->|
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* ciphertext
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*
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* Returns std::size_t(-1) if the length of the plain-text buffer is too
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* small or if the authentication check fails. Otherwise returns the length
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* of the plain text.
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*/
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virtual std::size_t decrypt(
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std::uint8_t const * key, std::size_t key_length,
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t const * ciphertext, std::size_t ciphertext_length,
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std::uint8_t * plaintext, std::size_t max_plaintext_length
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) const = 0;
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};
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class CipherAesSha256 : public Cipher {
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public:
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CipherAesSha256(
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std::uint8_t const * kdf_info, std::size_t kdf_info_length
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);
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virtual std::size_t mac_length() const;
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virtual std::size_t encrypt_ciphertext_length(
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std::size_t plaintext_length
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) const;
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virtual std::size_t encrypt(
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std::uint8_t const * key, std::size_t key_length,
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std::uint8_t const * plaintext, std::size_t plaintext_length,
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std::uint8_t * ciphertext, std::size_t ciphertext_length,
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std::uint8_t * output, std::size_t output_length
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) const;
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virtual std::size_t decrypt_max_plaintext_length(
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std::size_t ciphertext_length
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) const;
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virtual std::size_t decrypt(
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std::uint8_t const * key, std::size_t key_length,
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t const * ciphertext, std::size_t ciphertext_length,
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std::uint8_t * plaintext, std::size_t max_plaintext_length
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) const;
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private:
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std::uint8_t const * kdf_info;
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std::size_t kdf_info_length;
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};
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} // namespace
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#endif /* AXOLOTL_CIPHER_HH_ */
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