May 25, 2011

Statistical podcast: random number seeds

Filed under: Computing, Geekery — Tags: , , , , — csgillespie @ 10:39 pm

One of the podcasts I listen to each week is Security Now! Typically, this podcast has little statistical content, as its main focus is computer security, but episode 301 looks at how to generate truly random numbers for seeding pseudo random number generators.

Generating truly random numbers to be used as a seed, turns out to be rather tricky. For example, in the Netscape browser, the random seed used by version 1.0 of the SSL protocol combined the time of day and the process number to seed its random number generator. However, it turns out that the process number is usually a small subset of all possible ids, and so is fairly easy to guess.

Recent advances indicate that we can get “almost true” randomness by taking multiple snap shorts of the processor counter. Since the counter covers around 3 billion numbers each second, we can use the counter to create a true random seed.

To find out more, listen to the podcast. The discussion on random seeds begins mid-way through the podcast.

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