void ANSI_X931_RNG::randomize(byte out[], size_t length)
{
if(!is_seeded())
{
reseed(BOTAN_RNG_RESEED_POLL_BITS);
if(!is_seeded())
throw PRNG_Unseeded(name());
}
while(length)
{
if(m_R_pos == m_R.size())
update_buffer();
const size_t copied = std::min<size_t>(length, m_R.size() - m_R_pos);
copy_mem(out, &m_R[m_R_pos], copied);
out += copied;
length -= copied;
m_R_pos += copied;
}
}
void Stateful_RNG::reseed_check()
{
const uint32_t cur_pid = OS::get_process_id();
const bool fork_detected = (m_last_pid > 0) && (cur_pid != m_last_pid);
if(is_seeded() == false ||
fork_detected ||
(m_reseed_interval > 0 && m_reseed_counter >= m_reseed_interval))
{
m_reseed_counter = 0;
m_last_pid = cur_pid;
if(m_underlying_rng)
{
reseed_from_rng(*m_underlying_rng, security_level());
}
if(m_entropy_sources)
{
reseed(*m_entropy_sources, security_level());
}
if(!is_seeded())
{
if(fork_detected)
throw Exception("Detected use of fork but cannot reseed DRBG");
else
throw PRNG_Unseeded(name());
}
}
else
{
BOTAN_ASSERT(m_reseed_counter != 0, "RNG is seeded");
m_reseed_counter += 1;
}
}
/*************************************************
* Add entropy to internal state *
*************************************************/
void ANSI_X931_RNG::add_randomness(const byte data[], u32bit length)
{
prng->add_entropy(data, length);
if(is_seeded())
{
SecureVector<byte> key(cipher->MAXIMUM_KEYLENGTH);
prng->randomize(key, key.size());
cipher->set_key(key, key.size());
prng->randomize(V, V.size());
update_buffer();
}
}
/**
* Generate a buffer of random bytes
*/
void ANSI_X931_RNG::randomize(byte out[], u32bit length)
{
if(!is_seeded())
throw PRNG_Unseeded(name());
while(length)
{
if(position == R.size())
update_buffer();
const u32bit copied = std::min(length, R.size() - position);
copy_mem(out, R + position, copied);
out += copied;
length -= copied;
position += copied;
}
}
