Mads Haahr, moderator and operator of random.org, a random number generator, wrote in an e-mail that Internet data encryption is one of the most common applications of random numbers.

The random number generators on Random.org, however, are true random number generators, and can be used to generate random sequences of integers, Gaussian distributions, and DNA and protein ...

But the random number generator they built was, they reasoned, still useful. So Haahr made it public at random.org, where it has been churning out random numbers ever since. It gets a lot of visitors.

The Random Number Generator is a tool that could be useful for genearting encryption keys for secure communications between activist organizations, or anyone concerned with privacy and security. From ...

The company needed some truly random numbers for its security solutions, so it turned to some groovy old tech: lava lamps. In their office is a wall of 100 lava lamps monitored by cameras.

The best we can do is to generate long sequences that have some of the key properties of random numbers. The programs that do this are called pseudo-random number generators.