Function GetStrongRandBytes

src/random.cpp:318–351

}

void GetStrongRandBytes(unsigned char* out, int num)
{
    assert(num <= 32);
    CSHA512 hasher;
    unsigned char buf[64];

    // First source: OpenSSL's RNG
    RandAddSeedPerfmon();
    GetRandBytes(buf, 32);
    hasher.Write(buf, 32);

    // Second source: OS RNG
    GetOSRand(buf);
    hasher.Write(buf, 32);

    // Third source: HW RNG, if available.
    if (GetHWRand(buf)) {
        hasher.Write(buf, 32);
    }

    // Combine with and update state
    {
        std::unique_lock<std::mutex> lock(cs_rng_state);
        hasher.Write(rng_state, sizeof(rng_state));
        hasher.Write((const unsigned char*)&rng_counter, sizeof(rng_counter));
        ++rng_counter;
        hasher.Finalize(buf);
        memcpy(rng_state, buf + 32, 32);
    }

    // Produce output
    memcpy(out, buf, num);
    memory_cleanse(buf, 64);
}

uint64_t GetRand(uint64_t nMax)
{