I am currently developing a distributed application where many clients need to generate unique 64-bit random numbers which will be used as keys. I am having problems getting boost to do this. For my first attempt, I tried something like the following: boost::mt19937 RandomNumberGenerator::s_algorithm; boost::uniform_int<unsigned long long> RandomNumberGenerator::s_range( std::numeric_limits<unsigned long long>::min(), std::numeric_limits<unsigned long long>::max()); boost::variate_generator<boost::mt19937&, boost::uniform_int<unsigned long long> > RandomNumberGenerator::s_rng(RandomNumberGenerator::s_algorithm, RandomNumberGenerator::s_range); I had two issues though: 1. Is this really giving me random 64 bit numbers, or is it just generating 32-bit numbers and then doing bit expansion? 2. The values always started with the same number. Trying to find a fix for #2, I though of using a hashed GUID as a seed. The problem is I noticed the seed value takes a 32 bit int, which essentially means a 1/2^32 chance of the first value colliding even if chosen completely randomly, which is unacceptable for my application. I am back where I started. Is there any clean way to use boost to generate random 64-bit intergers, when the same application is going to be run across multiple computers?