Hello,
> Just to add to the list below:
>
> OpenSSL> version
> OpenSSL 0.9.8b 04 May 2006
> OpenSSL> prime 2
> 2 is prime
To be sure we should use another library:
$ cat gmp5.c
#include <stdio.h>
#include <gmp.h>
int main()
{
mpz_t t;
int rc;
mpz_init_set_str(t, "2", 10);
rc = mpz_probab_prime_p(t, 1000);
printf("rc=%d\n", rc);
return(0);
}
$ gcc -o gmp5 gmp5.c -lgmp
$ ./gmp5
rc=2
and return code 2 in GMP means "definitely prime".
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Victor Duchovni
> Sent: Monday, March 05, 2007 4:24 PM
> To: openssl-users@openssl.org
> Subject: Re: 2 is not prime?
>
> On Mon, Mar 05, 2007 at 02:06:19PM -0800, Brandon Ooi wrote:
>
> > Hi,
> >
> > Sorry if this is a dumb question but I couldn't find the openssl
> > bugzilla (or equivalent) to look for this. I was using openssl to
> > check primes and kept running into these weird issues until I found
> this...
> >
> > $ openssl version
> > OpenSSL 0.9.7f 22 Mar 2005
> > $ openssl prime 2
> > 2 is not prime
>
> $ 0.9.6/bin/openssl version
> OpenSSL 0.9.6m 17 Mar 2004
> $ 0.9.6/bin/openssl prime 2
> openssl:Error: 'prime' is an invalid command.
> ... copious usage ...
>
> $ 0.9.7/bin/openssl version
> OpenSSL 0.9.7l 28 Sep 2006
> $ 0.9.7/bin/openssl prime 2
> 2 is not prime
>
> $ 0.9.8/bin/openssl version
> OpenSSL 0.9.8d 28 Sep 2006
> $ 0.9.8/bin/openssl prime 2
> 2 is prime
>
> $ 0.9.9/bin/openssl version
> OpenSSL 0.9.9-dev XX xxx XXXX
> $ openssl prime 2
> 2 is prime
>
> > But.. 2 is prime right?
>
> Yes.
>
> > Anyways, it's not a huge issue but this could be a bigger bug?
>
> Not likely, just a failure in 0.9.7 to exclude 2 from the set of
> composite even numbers.
>
--
Marek Marcola <[EMAIL PROTECTED]>
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