libcruft-crypto/hash/blake.hpp

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2018 Danny Robson <danny@nerdcruft.net>
 */

#ifndef CRUFT_CRYPTO_HASH_BLAKE_HPP
#define CRUFT_CRYPTO_HASH_BLAKE_HPP

#include <cruft/util/view.hpp>

#include <array>

#include <cstdint>
#include <cstdlib>


///////////////////////////////////////////////////////////////////////////////
namespace cruft::crypto::hash {

    ///////////////////////////////////////////////////////////////////////////
    template <int>
    struct traits {};


    //-------------------------------------------------------------------------
    template <>
    struct traits<256>
    {
        using word_t = uint32_t;

        static const std::array<word_t,8> iv;
        static const std::array<word_t,16> pi;
        static const std::array<int,4> rotations;
        static constexpr int rounds = 14;
    };


    //-------------------------------------------------------------------------
    template <>
    struct traits<224>
    {
        using word_t = traits<256>::word_t;
    };


    //-------------------------------------------------------------------------
    template <>
    struct traits<512>
    {
        using word_t = uint64_t;

        static const std::array<word_t,8> iv;
        static const std::array<word_t,16> pi;
        static const std::array<int,4> rotations;
        static constexpr int rounds = 16;
    };


    //-------------------------------------------------------------------------
    template <>
    struct traits<384>
    {
        using word_t = traits<512>::word_t;
    };


    /// an implementation of the BLAKE hash function
    ///
    /// note that this is _not_ BLAKE2, but the original SHA-3 candidate
    /// function.
    ///
    /// \tparam width   the number of bits for the digest
    template <int width>
    class blake {
    public:
        using word_t = typename traits<width>::word_t;

        // size of each round's data block in bytes
        static const size_t block_size  = 16 * sizeof (word_t);

        // size of the digest in bytes
        static const size_t digest_size = width / 8;
        using digest_t = std::array<uint8_t,digest_size>;


        digest_t operator() (
            util::view<const uint8_t*> data,
            util::view<const uint8_t*> salt
        ) const;

        digest_t operator() (util::view<const uint8_t*> data,
                             const std::array<word_t,4> salt) const noexcept;

        digest_t operator() (util::view<const uint8_t*> data) const noexcept
        {
            return (*this) (data, {0,0,0,0});
        }
    };
}

#endif