cbc_mac.hpp

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//---------------------------------------------------------------------------//
// Copyright (c) 2019 Mikhail Komarov <nemo@nil.foundation>
//
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//---------------------------------------------------------------------------//
 
#ifndef CRYPTO3_MAC_CBC_MAC_HPP
#define CRYPTO3_MAC_CBC_MAC_HPP
 
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
 
#include <nil/crypto3/mac/detail/cbc_mac/cbc_mac_policy.hpp>
#include <nil/crypto3/mac/detail/cbc_mac/accumulator.hpp>
 
namespace nil {
    namespace crypto3 {
        namespace mac {
            template<typename BlockCipher>
            class cbc_mac {
                typedef detail::cbc_mac_policy<BlockCipher> policy_type;
 
            public:
                typedef BlockCipher block_cipher_type;
 
                constexpr static const std::size_t block_bits = policy_type::block_bits;
                constexpr static const std::size_t block_words = policy_type::block_words;
                typedef typename policy_type::block_type block_type;
 
                constexpr static const std::size_t key_bits = policy_type::key_bits;
                constexpr static const std::size_t key_words = policy_type::key_words;
                typedef typename policy_type::key_type key_type;
 
                constexpr static const std::size_t state_bits = policy_type::state_bits;
                constexpr static const std::size_t state_words = policy_type::state_words;
                typedef typename policy_type::state_type state_type;
 
                constexpr static const std::size_t digest_bits = policy_type::digest_bits;
                typedef typename policy_type::digest_type digest_type;
 
                cbc_mac(const block_cipher_type &cipher) : cipher(cipher) {
                }
 
                cbc_mac(const key_type &key) : cipher(key) {
                }
 
                inline void begin_message(state_type &state, const block_type &block) {
                    size_t xored = std::min(output_length() - m_position, length);
                    xor_buf(&m_state[m_position], input, xored);
                    m_position += xored;
 
                    if (m_position < output_length()) {
                        return;
                    }
 
                    m_cipher->encrypt(m_state);
                    input += xored;
                    length -= xored;
                    while (length >= output_length()) {
                        xor_buf(m_state, input, output_length());
                        m_cipher->encrypt(m_state);
                        input += output_length();
                        length -= output_length();
                    }
 
                    xor_buf(m_state, input, length);
                    m_position = length;
                }
 
                void process_block(state_type &state, const block_type &block) {
                    size_t xored = std::min(output_length() - m_position, length);
                    xor_buf(&m_state[m_position], input, xored);
                    m_position += xored;
 
                    if (m_position < output_length()) {
                        return;
                    }
 
                    m_cipher->encrypt(m_state);
                    input += xored;
                    length -= xored;
                    while (length >= output_length()) {
                        xor_buf(m_state, input, output_length());
                        m_cipher->encrypt(m_state);
                        input += output_length();
                        length -= output_length();
                    }
 
                    xor_buf(m_state, input, length);
                    m_position = length;
                }
 
                void end_message(digest_type &digest, const state_type &state, const block_type &block) {
                    if (m_position) {
                        m_cipher->encrypt(m_state);
                    }
 
                    copy_mem(mac, m_state.data(), m_state.size());
                    zeroise(m_state);
                    m_position = 0;
                }
 
            protected:
                void schedule_key(const key_type &key) {
                }
 
                block_cipher_type cipher;
            };
        }    // namespace mac
    }        // namespace crypto3
}    // namespace nil
 
#endif