RSA Laboratories

RSA-640 is factored!

The factoring research team of F. Bahr, M. Boehm, J. Franke, T. Kleinjung continued its productivity with a successful factorization of the challenge number RSA-640, reported on November 2, 2005. The factors [verified by RSA Laboratories] are:

16347336458092538484431338838650908598417836700330
92312181110852389333100104508151212118167511579

and

1900871281664822113126851573935413975471896789968
515493666638539088027103802104498957191261465571

The effort took approximately 30 2.2GHz-Opteron-CPU years according to the submitters, over five months of calendar time. (This is about half the effort for RSA-200, the 663-bit number that the team factored in 2004.)

Notes: