Why?

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.

January 14, 2011

Statistical podcast: Random and Pseudorandom

Filed under: Geekery, R — Tags: , , , , — csgillespie @ 10:01 am

This morning when I downloaded the latest version of In our time, I was pleased to see that this weeks topic was “Random and Pexkcd Random cartoonudorandom.” If you’re not familiar with “In our time”, then I can I definitely recommend the series. Each week three academics and Melvyn Bragg discuss a particular topic from history, science, philosophy, or religion. This weeks guests were Prof Marcus du Sautoy, Dr Colva Roney-Dougal and Prof Timothy Gowers. The discussion is aimed at the general public, but the phrase “dumbing down” certainly doesn’t apply! For example,  the introductory statement to the Mathematics episode is

Hello, Galileo wrote, “This grand book, the universe is written in the language of mathematics”. It was said before Galileo, and has been said since, and in the last decade of the 20th century, it’s being said again, most emphatically. So how important is maths in relation to other sciences at the end of the 20th century? What insight can it give us into the origins of life and the functioning of our brains? And what does it mean to say that mathematics has become more visual?

 

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