cmac.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_CMAC_HPP
#define CRYPTO3_MAC_CMAC_HPP
 
#include <nil/crypto3/detail/poly_dbl.hpp>
 
#include <nil/crypto3/mac/detail/cmac/cmac_policy.hpp>
#include <nil/crypto3/mac/detail/cmac/accumulator.hpp>
 
namespace nil {
    namespace crypto3 {
        namespace mac {
            template<typename BlockCipher>
            class cmac {
                typedef detail::cmac_policy<BlockCipher> policy_type;
 
            public:
                typedef BlockCipher 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 digest_bits = policy_type::digest_bits;
                typedef typename policy_type::digest_type digest_type;
 
                cmac(const cipher_type &cipher) : cipher(cipher) {
                    BOOST_STATIC_ASSERT(poly_double_supported_size(cipher_type::block_bits / CHAR_BIT));
                }
 
                cmac(const key_type &key) : cipher(key) {
                }
 
                inline void begin_message(const block_type &block) const {
                    return process_block(block);
                }
 
                inline void process_block(const block_type &block) const {
                    const size_t bs = output_length();
 
                    buffer_insert(m_buffer, m_position, input, length);
                    if (m_position + length > bs) {
                        xor_buf(m_state, m_buffer, bs);
                        m_cipher->encrypt(m_state);
                        input += (bs - m_position);
                        length -= (bs - m_position);
                        while (length > bs) {
                            xor_buf(m_state, input, bs);
                            m_cipher->encrypt(m_state);
                            input += bs;
                            length -= bs;
                        }
                        copy_mem(m_buffer.data(), input, length);
                        m_position = 0;
                    }
                    m_position += length;
                }
 
                inline void end_message(const block_type &block) const {
                    xor_buf(m_state, m_buffer, m_position);
 
                    if (m_position == output_length()) {
                        xor_buf(m_state, m_B, output_length());
                    } else {
                        m_state[m_position] ^= 0x80;
                        xor_buf(m_state, m_P, output_length());
                    }
 
                    m_cipher->encrypt(m_state);
 
                    copy_mem(mac, m_state.data(), output_length());
 
                    zeroise(m_state);
                    zeroise(m_buffer);
                    m_position = 0;
                }
 
            protected:
                void schedule_key(const key_type &key) {
                    using namespace nil::crypto3::detail;
 
                    cipher.encrypt_block(m_B);
                    poly_double_n(m_B.data(), m_B.size());
                    poly_double_n(m_P.data(), m_B.data(), m_P.size());
                }
 
                cipher_type cipher;
            };
 
            template<typename BlockCipher>
            using omac1 = cmac<BlockCipher>;
        }    // namespace mac
    }        // namespace crypto3
}    // namespace nil
 
#endif