#ifndef FORTUNA_GENERATOR_H
#define FORTUNA_GENERATOR_H
#include <cryptopp/cryptlib.h>
#include <cryptopp/modes.h>
#include <cryptopp/secblock.h>
#include <cryptopp/serpent.h>
#include <array>
#include <chrono>
#include <cstdint>
#include <mutex>
#include <string>
namespace fortuna {
namespace generator {
class Generator {
public:
std::chrono::milliseconds reseed_interval{100};
mutable std::recursive_mutex mtx;
std::mutex crypt_mtx;
std::mutex reseed_mtx;
Generator(); // ad noexcept: perhaps _do_ throw*
Generator(const Generator& Gen) = delete; // no
Generator& operator=(const Generator& Gen) = delete; // copies
~Generator() noexcept;
/* n is the number of random bytes to generate */
auto generate_random_data(const uint64_t& n) -> std::string;
auto reseed(const std::string& s) -> void;
[[optimize_for_synchronized]] auto time_to_reseed(
const uint64_t& pool0_len,
const unsigned int& min_p_size,
const std::chrono::duration<int64_t, std::ratio<1, 1000>>& time_elapsed,
const std::chrono::milliseconds& reseed_interval) const -> bool;
auto is_seeded() const -> bool {
std::lock_guard<std::recursive_mutex> lg(mtx);
return !(this->G.ctr == this->null_blk);
}
private:
static constexpr const std::size_t ctr_len{16};
static constexpr const std::array<std::byte, ctr_len> null_blk{
std::byte{0x00},
}; // used for comparison with G.ctr in is_seeded() and generate_blocks()
CryptoPP::CTR_Mode<CryptoPP::Serpent>::Encryption enc;
struct G_state {
static constexpr const std::size_t k_length{32};
CryptoPP::FixedSizeSecBlock<CryptoPP::byte, k_length> k;
std::array<std::byte, ctr_len> ctr;
};
G_state G;
void initialize_generator();
auto do_crypto() -> std::string;
auto generate_blocks(unsigned int k_blocks) -> std::string;
auto ctr_inc() -> void;
protected:
auto get_state() const -> Generator::G_state;
}; // class generator
} // namespace generator
} // namespace fortuna
#endif // FORTUNA_GENERATOR_H
