//
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// Copyright (c) 2017 James E. King III
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// https://www.boost.org/LICENSE_1_0.txt)
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//
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// BCrypt provider for entropy
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//
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#include <cstddef>
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#include <boost/config.hpp>
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#include <boost/core/ignore_unused.hpp>
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#include <boost/move/core.hpp>
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#include <boost/numeric/conversion/cast.hpp>
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#include <boost/winapi/bcrypt.hpp>
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#include <boost/winapi/get_last_error.hpp>
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#include <boost/throw_exception.hpp>
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#if defined(BOOST_UUID_FORCE_AUTO_LINK) || (!defined(BOOST_ALL_NO_LIB) && !defined(BOOST_UUID_RANDOM_PROVIDER_NO_LIB))
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# define BOOST_LIB_NAME "bcrypt"
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# if defined(BOOST_AUTO_LINK_NOMANGLE)
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# include <boost/config/auto_link.hpp>
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# else
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# define BOOST_AUTO_LINK_NOMANGLE
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# include <boost/config/auto_link.hpp>
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# undef BOOST_AUTO_LINK_NOMANGLE
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# endif
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#endif
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namespace boost {
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namespace uuids {
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namespace detail {
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class random_provider_base
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{
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BOOST_MOVABLE_BUT_NOT_COPYABLE(random_provider_base)
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public:
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random_provider_base()
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: hProv_(NULL)
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{
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boost::winapi::NTSTATUS_ status =
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boost::winapi::BCryptOpenAlgorithmProvider(
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&hProv_,
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boost::winapi::BCRYPT_RNG_ALGORITHM_,
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NULL,
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0);
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if (BOOST_UNLIKELY(status != 0))
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{
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BOOST_THROW_EXCEPTION(entropy_error(status, "BCryptOpenAlgorithmProvider"));
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}
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}
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random_provider_base(BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT : hProv_(that.hProv_)
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{
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that.hProv_ = NULL;
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}
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random_provider_base& operator= (BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT
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{
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destroy();
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hProv_ = that.hProv_;
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that.hProv_ = NULL;
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return *this;
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}
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~random_provider_base() BOOST_NOEXCEPT
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{
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destroy();
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}
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//! Obtain entropy and place it into a memory location
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//! \param[in] buf the location to write entropy
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//! \param[in] siz the number of bytes to acquire
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void get_random_bytes(void *buf, std::size_t siz)
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{
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boost::winapi::NTSTATUS_ status =
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boost::winapi::BCryptGenRandom(
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hProv_,
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static_cast<boost::winapi::PUCHAR_>(buf),
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boost::numeric_cast<boost::winapi::ULONG_>(siz),
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0);
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if (BOOST_UNLIKELY(status != 0))
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{
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BOOST_THROW_EXCEPTION(entropy_error(status, "BCryptGenRandom"));
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}
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}
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private:
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void destroy() BOOST_NOEXCEPT
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{
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if (hProv_)
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{
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boost::ignore_unused(boost::winapi::BCryptCloseAlgorithmProvider(hProv_, 0));
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}
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}
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private:
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boost::winapi::BCRYPT_ALG_HANDLE_ hProv_;
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};
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} // detail
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} // uuids
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} // boost
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