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e S- b4t or^t1 fu e t - t "RSA-640", a 640 bit - - PDF document

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SLIDE 1

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SLIDE 2

"RSA-640", a 640 bit (193-digits) number was factored in 2005 using 30 CPU-years on a cluster of 2.2 GHz Opterons (5 months elapsed). The graph below extrapolates this to other lengths, assuming complexity scales as:

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If you're worried about someone spending 30 CPU-years to crack your email chatter, what could you do? Double your key length. That will slow en-/decryption by < 8 x (they're sub-cubic algorithms), but slow factoring by 10^8 x.

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SLIDE 3

'Eqf-640", a 640.bit (1g3-digits) number was factored in 2OO5 using gO CPU-years

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lf you?e worried about someone spending g0 Cpu-years to crack your emaif chatter, what could vou do? Double vour kei lenoth. That n;ill slow en-/decryption by **i (rhey?e g.glklic atgoritnmS;, but stow

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