Saturday, September 29, 2018

[klqgajgx] Factoring as a benchmark

When describing the speed of a processor or computer system, consider expressing it as the number of bits it could factor in a year.  That is, the size in bits of a RSA number (semiprime) for which the computer could complete by itself just the sieving portion of the general number field sieve.  Sieving is embarrassingly parallel so doesn't incur difficulties about how good your interconnect is for parallel computers.

It's a practical and easily explainable computationally intensive problem that one could imagine anybody doing.  Dedicating one year to a computation is something one could imagine an individual doing, or (because embarrassingly parallel) one could imagine an organization buying 365 such computers to complete within a day.

It gives a hint of what size RSA keys are in danger today.

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