From winandy@informatik.uni-bonn.de Wed Apr 17 14:00:45 2002 From: winandy@informatik.uni-bonn.de (Marcel Winandy) Date: 2002年4月17日 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: 2002年4月19日 04:16:04 +1000 Subject: [Classpathx-crypto] Primes and BigInteger References: <3cbd71fd.95c8d91e@informatik.uni-bonn.de> Message-ID: <009901c1e7059ドルf5253b07201ドルb5ca@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" To: 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: 2002年4月25日 05:49:37 +1000 Subject: [Classpathx-crypto] Build system. References: <87it6h6nzz.fsf@pooh-sticks-bridge.tapsellferrier.co.uk> Message-ID: <004701c1ebc92ドルb36a5806ドルf02b5ca@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" To: 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>

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