entropy.cpp - mozsearch

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/*

* (C) 2019 Jack Lloyd

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include "cli.h"

#include "../tests/test_rng.h" // FIXME

#include <botan/entropy_src.h>

#if defined(BOTAN_HAS_COMPRESSION)

#include <botan/compression.h>

#endif

namespace Botan_CLI {

class Entropy final : public Command

   public:

      Entropy() : Command("entropy --truncate-at=128 source") {}

      std::string group() const override

         return "misc";

      std::string description() const override

         return "Sample a raw entropy source";

      void go() override

         const std::string req_source = get_arg("source");

         const size_t truncate_sample = get_arg_sz("truncate-at");

         auto& entropy_sources = Botan::Entropy_Sources::global_sources();

         std::vector<std::string> sources;

         if(req_source == "all")

            sources = entropy_sources.enabled_sources();

         else

            sources.push_back(req_source);

         for(std::string source : sources)

            Botan_Tests::SeedCapturing_RNG rng;

            const size_t entropy_estimate = entropy_sources.poll_just(rng, source);

            if(rng.samples() == 0)

               output() << "Source " << source << " is unavailable\n";

               continue;

            const auto& sample = rng.seed_material();

            output() << "Polling " << source << " gathered " << sample.size()

                     << " bytes in " << rng.samples() << " outputs with estimated entropy "

                     << entropy_estimate << "\n";

#if defined(BOTAN_HAS_COMPRESSION)

            if(!sample.empty())

               std::unique_ptr<Botan::Compression_Algorithm> comp(Botan::make_compressor("zlib"));

               if(comp)

try

                     Botan::secure_vector<uint8_t> compressed;

                     compressed.assign(sample.begin(), sample.end());

                     comp->start(9);

                     comp->finish(compressed);

                     if(compressed.size() < sample.size())

                        output() << "Sample from " << source << " was zlib compressed from " << sample.size()

                                 << " bytes to " << compressed.size() << " bytes\n";

                  catch(std::exception& e)

                     error_output() << "Error while attempting to compress: " << e.what() << "\n";

#endif

            if(sample.size() <= truncate_sample)

               output() << Botan::hex_encode(sample) << "\n";

            else if(truncate_sample > 0)

               output() << Botan::hex_encode(&sample[0], truncate_sample) << "...\n";

};

BOTAN_REGISTER_COMMAND("entropy", Entropy);