Displaying 4 results from an estimated 4 matches for "is_prime".
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2015 May 22
4
Weak DH primes and openssh
On Fri 2015-05-22 00:06:29 -0400, Darren Tucker wrote:
> On Thu, May 21, 2015 at 11:26 PM, Matthew Vernon <matthew at debian.org> wrote:
>>
>> You will be aware of https://weakdh.org/ by now, I presume; the
>> take-home seems to be that 1024-bit DH primes might well be too weak.
>> I'm wondering what (if anything!) you propose to do about this issue,
>>
2015 May 26
8
Weak DH primes and openssh
...ty ("Smallest odd number for which Miller-Rabin
primality test on bases <= n-th prime does not reveal compositeness").
Taking the final integer in that sequence (a(11)) fails even the default
25-round M-R test in gmp:
>>> k = gmpy2.mpz(3825123056546413051)
>>> gmpy2.is_prime(k)
False
>>>
Indeed, the arxiv suggests that in 2012 people were still writing proofs
about a(11) for this sequence:
http://arxiv.org/abs/1207.0063
but i see no evidence that an algorithm for generating a(n) where n is
arbitrarily large exists. Does such a thing exist?
> yes, us...
2015 May 26
2
Weak DH primes and openssh
On Tue 2015-05-26 12:57:05 -0400, Hubert Kario wrote:
> creating composites that will pass even 100000 rounds of Miller-Rabin is
> relatively simple....
> (assuming the values for M-R tests are picked randomly)
Can you point me to the algorithms for doing that? This would suggest
that we really do want primality proofs (and a good way to verify them).
Do those algorithms hold for
2015 May 27
3
Weak DH primes and openssh
...rimality test on bases <= n-th prime does not reveal compositeness").
>>
>> Taking the final integer in that sequence (a(11)) fails even the default
>>
>> 25-round M-R test in gmp:
>> >>> k = gmpy2.mpz(3825123056546413051)
>> >>> gmpy2.is_prime(k)
>>
>> False
>
> I'm quite sure that this means that gmpy doesn't use pure M-R with randomly
> selected witnesses.
https://gmplib.org/manual/Prime-Testing-Algorithm.html#Prime-Testing-Algorithm
suggests is chooses a random base, but it also runs some non-M-R tests...