RSA-640
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In mathematics, RSA-640 is one of the RSA numbers - large semiprimes that are part of the RSA Factoring Challenge. RSA-640 has a length of 193 decimal digits. A cash prize of US$20,000 had been offered by RSA Security for a successful factorisation. On 2 November 2005, F. Bahr, M. Boehm, J. Franke and T. Kleinjung of the German Federal Agency for Information Technology Security (BSI) announced that they had factorised the number using GNFS as follows:
RSA-640 = 31074182404900437213507500358885679300373460228427275457 201619488232064405180815045563468296717232867824379162728380334154 710731085019195485290073377248227835257423864540146917366024776523 46609
Factor 1: 16347336458092538484431338838650908598417836700330923121 81110852389333100104508151212118167511579
Factor 2: 19008712816648221131268515739354139754718967899685154936 66638539088027103802104498957191261465571
The computation took 5 months on 80 2.2 GHz Opteron CPUs.
RSA-200, a slightly larger number at 663 bits, was factored in May 2005 by the same team.
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External links
- RSA Factoring Challenge: RSA-640
- Announcement of factorisation
- Mathworld article, Eric W. Weisstein, 8th November 2005.fr:RSA-640