Files
rippled/src/ripple/crypto/impl/csprng.cpp

139 lines
3.5 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2012, 2013 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include <ripple/basics/contract.h>
#include <ripple/basics/ByteUtilities.h>
#include <ripple/crypto/csprng.h>
#include <openssl/rand.h>
#include <array>
#include <cassert>
#include <random>
#include <stdexcept>
namespace ripple {
void
csprng_engine::mix (
void* data, std::size_t size, double bitsPerByte)
{
assert (data != nullptr);
assert (size != 0);
assert (bitsPerByte != 0);
std::lock_guard<std::mutex> lock (mutex_);
RAND_add (data, size, (size * bitsPerByte) / 8.0);
}
csprng_engine::csprng_engine ()
{
mix_entropy ();
}
csprng_engine::~csprng_engine ()
{
RAND_cleanup ();
}
void
csprng_engine::load_state (std::string const& file)
{
if (!file.empty())
{
std::lock_guard<std::mutex> lock (mutex_);
RAND_load_file (file.c_str (), kilobytes(1));
RAND_write_file (file.c_str ());
}
}
void
csprng_engine::save_state (std::string const& file)
{
if (!file.empty())
{
std::lock_guard<std::mutex> lock (mutex_);
RAND_write_file (file.c_str ());
}
}
void
csprng_engine::mix_entropy (void* buffer, std::size_t count)
{
std::array<std::random_device::result_type, 128> entropy;
{
// On every platform we support, std::random_device
// is non-deterministic and should provide some good
// quality entropy.
std::random_device rd;
for (auto& e : entropy)
e = rd();
}
// Assume 2 bits per byte for the system entropy:
mix (
entropy.data(),
entropy.size() * sizeof(std::random_device::result_type),
2.0);
// We want to be extremely conservative about estimating
// how much entropy the buffer the user gives us contains
// and assume only 0.5 bits of entropy per byte:
if (buffer != nullptr && count != 0)
mix (buffer, count, 0.5);
}
csprng_engine::result_type
csprng_engine::operator()()
{
result_type ret;
std::lock_guard<std::mutex> lock (mutex_);
auto const result = RAND_bytes (
reinterpret_cast<unsigned char*>(&ret),
sizeof(ret));
if (result == 0)
Throw<std::runtime_error> ("Insufficient entropy");
return ret;
}
void
csprng_engine::operator()(void *ptr, std::size_t count)
{
std::lock_guard<std::mutex> lock (mutex_);
auto const result = RAND_bytes (
reinterpret_cast<unsigned char*>(ptr),
count);
if (result != 1)
Throw<std::runtime_error> ("Insufficient entropy");
}
csprng_engine& crypto_prng()
{
static csprng_engine engine;
return engine;
}
}