From winandy@informatik.uni-bonn.de  Wed Apr 17 14:00:45 2002
From: winandy@informatik.uni-bonn.de (Marcel Winandy)
Date: Wed, 17 Apr 2002 15:00:45 +0200
Subject: [Classpathx-crypto] Primes and BigInteger
Message-ID: <3CBD71FD.95C8D91E@informatik.uni-bonn.de>

Hello!

I've just read that you were wondering about some large primes for which
java.math.BigInteger.isProbablePrime() returns 'false'. Well, BigInteger
has indeed a bug in its primality test. BigInteger runs Miller-Rabin
first. If Miller-Rabin returns 'probable prime' for some number, a
second test will be made, using Lucas this time. And there is a bug in
that Lucas algorithm of BigInteger. I don't know exactly what is is,
because a friend of mine examined several primality test algorithms. He
found that bug in BigInteger and told me. However, it was a very silly
mistake as far as I remeber - something like +1 instead of -1. But the
consequences are enormous - as you have seen.

I hope it will help you.

Bye,
 Marcel
-- 
Marcel Winandy
EMail: winandy@informatik.uni-bonn.de
http://www-student.informatik.uni-bonn.de/~winandy/


From raif@fl.net.au  Thu Apr 18 19:16:04 2002
From: raif@fl.net.au (Raif S. Naffah)
Date: Fri, 19 Apr 2002 04:16:04 +1000
Subject: [Classpathx-crypto] Primes and BigInteger
References: <3CBD71FD.95C8D91E@informatik.uni-bonn.de>
Message-ID: <009901c1e705$9f5253b0$7201b5ca@solomon>

well, i guessed it may be the case and that's why i asked for somebody who
can inspect the sources (of the JDK) to tell me/us more.  thanx for that.

the GNU crypto lib solves this problem by implementing a more reliable and i
think faster primality test based on Colin Plumb's tests (as the info page
states).

by the way, is there a bug number in the bug parade of Sun that points to
this problem?


cheers;
rsn
----- Original Message -----
From: "Marcel Winandy" <winandy@informatik.uni-bonn.de>
To: <classpathx-crypto@gnu.org>
Sent: Wednesday, April 17, 2002 11:00 PM
Subject: [Classpathx-crypto] Primes and BigInteger


> Hello!
>
> I've just read that you were wondering about some large primes for which
> java.math.BigInteger.isProbablePrime() returns 'false'. Well, BigInteger
> has indeed a bug in its primality test. BigInteger runs Miller-Rabin
> first. If Miller-Rabin returns 'probable prime' for some number, a
> second test will be made, using Lucas this time. And there is a bug in
> that Lucas algorithm of BigInteger. I don't know exactly what is is,
> because a friend of mine examined several primality test algorithms. He
> found that bug in BigInteger and told me. However, it was a very silly
> mistake as far as I remeber - something like +1 instead of -1. But the
> consequences are enormous - as you have seen.
>
> I hope it will help you.
>
> Bye,
>  Marcel
> --
> Marcel Winandy
> EMail: winandy@informatik.uni-bonn.de
> http://www-student.informatik.uni-bonn.de/~winandy/
>
> _______________________________________________
> Classpathx-crypto mailing list
> Classpathx-crypto@gnu.org
> http://mail.gnu.org/mailman/listinfo/classpathx-crypto
>



From nferrier@tapsellferrier.co.uk  Wed Apr 24 17:49:04 2002
From: nferrier@tapsellferrier.co.uk (Nic Ferrier)
Date: 24 Apr 2002 17:49:04 +0100
Subject: [Classpathx-crypto] Build system.
Message-ID: <87it6h6nzz.fsf@pooh-sticks-bridge.tapsellferrier.co.uk>

I've seen no comment on the build system that I put up on the FTP
site.

If no one has objected by next week I'll commit my changes to CVS.


Thanks.


Nic



From raif@fl.net.au  Wed Apr 24 20:49:37 2002
From: raif@fl.net.au (Raif S. Naffah)
Date: Thu, 25 Apr 2002 05:49:37 +1000
Subject: [Classpathx-crypto] Build system.
References: <87it6h6nzz.fsf@pooh-sticks-bridge.tapsellferrier.co.uk>
Message-ID: <004701c1ebc9$2b36a580$6f02b5ca@solomon>

i'll try it this weekend and will let you know how it fairs on my
W2k+cygwin.


cheers;
rsn
----- Original Message -----
From: "Nic Ferrier" <nferrier@tapsellferrier.co.uk>
To: <classpathx-crypto@gnu.org>
Sent: Thursday, April 25, 2002 2:49 AM
Subject: [Classpathx-crypto] Build system.


> I've seen no comment on the build system that I put up on the FTP
> site.
>
> If no one has objected by next week I'll commit my changes to CVS.
>
>
> Thanks.
>
>
> Nic
>
>
> _______________________________________________
> Classpathx-crypto mailing list
> Classpathx-crypto@gnu.org
> http://mail.gnu.org/mailman/listinfo/classpathx-crypto
>