Re: Fermat's primality test vs. Miller-Rabin

2005-11-14 Thread Travis H.
> > Although the Carmichael numbers fool the Fermat test > > (that is, $a^{n-1} = 1 (n)$) for *all* a, I thought it would work properly if a shares a factor with n. > Yes I guess the difference is that with MR you are trying to find a > number that is *likely* a prime, whereas with Fermat you are

Re: Fermat's primality test vs. Miller-Rabin

2005-11-14 Thread Alexander Klimov
On Fri, 11 Nov 2005, Joseph Ashwood wrote: > From: "Charlie Kaufman" <[EMAIL PROTECTED]> > > >I've heard but not confirmed a figure of one failure in 20 million. I've > >never heard an estimate of the probability that two runs would fail to > >detect the composite. It couldn't be better than one fa

Re: On Digital Cash-like Payment Systems

2005-11-14 Thread Travis H.
> Don't ever encrypt the same message twice that way, or you're likely to > fall to a common modulus attack, I believe. Looks like it (common modulus attack involves same n, different (e,d) pairs). However, you're likely to be picking a random symmetric key as the "message", and Schneier even sug

RE: On Digital Cash-like Payment Systems

2005-11-14 Thread Whyte, William
> > Don't ever encrypt the same message twice that way, or you're likely to > > fall to a common modulus attack, I believe. > > Looks like it (common modulus attack involves same n, > different (e,d) pairs). > > However, you're likely to be picking a random symmetric key as the > "message", and