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Implement DES block cipher #48

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Implement DES block cipher #48

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212 changes: 212 additions & 0 deletions include/nil/crypto3/block/des.hpp
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//---------------------------------------------------------------------------//
// Copyright (c) 2018-2020 Mikhail Komarov <nemo@nil.foundation>
// Copyright (c) 2020 Nikita Kaskov <nbering@nil.foundation>
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//---------------------------------------------------------------------------//

#ifndef CRYPTO3_BLOCK_DES_HPP
#define CRYPTO3_BLOCK_DES_HPP

#include <boost/endian/arithmetic.hpp>

#include <nil/crypto3/block/detail/des/des_functions.hpp>

#include <nil/crypto3/block/detail/block_stream_processor.hpp>
#include <nil/crypto3/block/detail/cipher_modes.hpp>

namespace nil {
namespace crypto3 {
namespace block {
/*!
* @brief DES. Triple DES. Originally designed by IBM and NSA in the 1970s.
*
* Today, DES's 56-bit key renders it insecure to any well-resourced
* attacker. DESX and 3DES extend the key length, and are still thought
* to be secure, modulo the limitation of a 64-bit block.
* All are somewhat common in some industries such as finance.
* Avoid in new code.
*
* @ingroup block
*/
class des {
protected:
typedef detail::des_functions<detail::des_policy> policy_type;

constexpr static const std::size_t key_schedule_size = policy_type::key_schedule_size;
typedef typename policy_type::key_schedule_type key_schedule_type;

public:
constexpr static const std::size_t word_bits = policy_type::word_bits;
typedef typename policy_type::word_type word_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;

template<class Mode, typename StateAccumulator, std::size_t ValueBits>
struct stream_processor {
struct params_type {

constexpr static const std::size_t value_bits = ValueBits;
constexpr static const std::size_t length_bits = policy_type::word_bits * 2;
};

typedef block_stream_processor<Mode, StateAccumulator, params_type> type;
};

typedef typename stream_endian::little_octet_big_bit endian_type;

des(const key_type &key) {
schedule_key(key);
}

~des() {
round_key.fill(0);
}

inline block_type encrypt(const block_type &plaintext) const {
return encrypt_block(plaintext);
}

inline block_type decrypt(const block_type &ciphertext) const {
return decrypt_block(ciphertext);
}

protected:
key_schedule_type round_key;

inline void schedule_key(const key_type &key) {
policy_type::des_key_schedule(round_key, key);
}

inline block_type encrypt_block(const block_type &plaintext) const {
block_type out;

word_type L, R;
policy_type::ip(L, R, plaintext);
policy_type::des_encrypt(L, R, round_key);
policy_type::fp(L, R, out);

return out;
}

inline block_type decrypt_block(const block_type &ciphertext) const {
block_type out;

word_type L, R;
policy_type::ip(L, R, ciphertext);
policy_type::des_decrypt(L, R, round_key);
policy_type::fp(L, R, out);

return out;
}
};

template<std::size_t KeyBits>
class triple_des {
protected:
typedef detail::des_functions<detail::triple_des_policy<KeyBits>> policy_type;

public:
constexpr static const std::size_t rounds = policy_type::rounds;

constexpr static const std::size_t word_bits = policy_type::word_bits;
typedef typename policy_type::word_type word_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 key_schedule_size = policy_type::key_schedule_size;
typedef typename policy_type::key_schedule_type key_schedule_type;

template<template<typename, typename> class Mode, typename StateAccumulator, std::size_t ValueBits,
typename Padding>
struct stream_processor {
struct params_type {
typedef typename stream_endian::little_octet_big_bit endian_type;

constexpr static const std::size_t value_bits = ValueBits;
constexpr static const std::size_t length_bits = policy_type::word_bits * 2;
};

typedef block_stream_processor<Mode<triple_des<KeyBits>, Padding>, StateAccumulator, params_type>
type;
};

triple_des(const key_type &key) {
schedule_key(key);
}

~triple_des() {
round_key.fill(0);
}

inline block_type encrypt(const block_type &plaintext) const {
return encrypt_block(plaintext);
}

inline block_type decrypt(const block_type &ciphertext) const {
return decrypt_block(ciphertext);
}

protected:
key_schedule_type round_key;

inline void schedule_key(const key_type &key) {
policy_type::des_key_schedule(&round_key[0], key);
policy_type::des_key_schedule(&round_key[32], key + 8);

if (key.size() == 24) {
policy_type::des_key_schedule(&round_key[64], key + 16);
} else {
copy_mem(&round_key[64], &round_key[0], 32);
}
}

inline block_type encrypt_block(const block_type &plaintext) const {
block_type out;
word_type L, R;

policy_type::ip(L, R, plaintext);

policy_type::des_encrypt(L, R, &round_key[0]);
policy_type::des_decrypt(R, L, &round_key[32]);
policy_type::des_encrypt(L, R, &round_key[64]);

policy_type::fp(L, R, out);

return out;
}

inline block_type decrypt_block(const block_type &ciphertext) const {
block_type out;
word_type L, R;

policy_type::ip(L, R, ciphertext);

policy_type::des_decrypt(L, R, &round_key[64]);
policy_type::des_encrypt(R, L, &round_key[32]);
policy_type::des_decrypt(L, R, &round_key[0]);

policy_type::fp(L, R, out);

return out;
}
};
} // namespace block
} // namespace crypto3
} // namespace nil

#endif
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