key length/size RSA discussion/recommendations in the wiki

Peter Lebbing peter at
Wed Oct 29 22:18:13 CET 2014

On 2014-10-29 21:49, vedaal at wrote:
> Surely Peter knows this too ;-)
> More likely 128 was a typo for the more common older RSA key of 1028 
> ...

No, I'm using a strict definition of brute force.

For p = 2^63 to 2^64-1
   For q = 2^63 to 2^64-1
     If p * q == n:

You're free to adapt the order of tries of p and q, though.

Happy breaking!

I don't feel the method outlined by Rob is still brute force. That 
brute actually is using his brain. Possibly his brain resembles a sieve, 
but still :). Am I too strict?


PS: I'm assuming a 128-bit RSA key is made up of two 64-bit primes.

I use the GNU Privacy Guard (GnuPG) in combination with Enigmail.
You can send me encrypted mail if you want some privacy.
My key is available at 

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