Method MixExtract

src/random.cpp:409–437

Extract up to 32 bytes of entropy from the RNG state, mixing in new entropy from hasher. * * If this function has never been called with strong_seed = true, false is returned. */

     * If this function has never been called with strong_seed = true, false is returned.
     */
    bool MixExtract(unsigned char* out, size_t num, CSHA512&& hasher, bool strong_seed) noexcept
    {
        assert(num <= 32);
        unsigned char buf[64];
        static_assert(sizeof(buf) == CSHA512::OUTPUT_SIZE, "Buffer needs to have hasher's output size");
        bool ret;
        {
            LOCK(m_mutex);
            ret = (m_strongly_seeded |= strong_seed);
            // Write the current state of the RNG into the hasher
            hasher.Write(m_state, 32);
            // Write a new counter number into the state
            hasher.Write((const unsigned char*)&m_counter, sizeof(m_counter));
            ++m_counter;
            // Finalize the hasher
            hasher.Finalize(buf);
            // Store the last 32 bytes of the hash output as new RNG state.
            memcpy(m_state, buf + 32, 32);
        }
        // If desired, copy (up to) the first 32 bytes of the hash output as output.
        if (num) {
            assert(out != nullptr);
            memcpy(out, buf, num);
        }
        // Best effort cleanup of internal state
        hasher.Reset();
        memory_cleanse(buf, 64);
        return ret;
    }
};

RNGState& GetRNGState() noexcept