From owner-freebsd-questions Fri Mar 5 0:48:49 1999 Delivered-To: freebsd-questions@freebsd.org Received: from alpha.comkey.com.au (alpha.comkey.com.au [203.9.152.215]) by hub.freebsd.org (Postfix) with SMTP id D03B314FA8 for ; Fri, 5 Mar 1999 00:48:44 -0800 (PST) (envelope-from gjb@comkey.com.au) Received: (qmail 15121 invoked by uid 1001); 5 Mar 1999 08:17:27 -0000 Message-ID: <19990305081727.15120.qmail@alpha.comkey.com.au> X-Posted-By: GBA-Post 1.04 06-Feb-1999 X-PGP-Fingerprint: 5A91 6942 8CEA 9DAB B95B C249 1CE1 493B 2B5A CE30 Date: Fri, 05 Mar 1999 18:17:27 +1000 From: Greg Black To: cjclark@home.com Cc: stuyman@confusion.net (Laurence Berland), questions@FreeBSD.ORG Subject: Re: Crypt References: <199903050455.XAA09072@cc942873-a.ewndsr1.nj.home.com> In-reply-to: <199903050455.XAA09072@cc942873-a.ewndsr1.nj.home.com> of Thu, 04 Mar 1999 23:55:59 EST Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > If anyone can either point me to the code > > or (and this would make me very happy) tell me the mathematical formulas > > on which one of these (or a more basic version of these) schemes works. > > It's all about factorization, division, and modulo operations on very > large whole numbers. If you are really interested in cryptography, > there are many, many sources that will be much better to start at than > source code. One of the best is Bruce Schneier's book "Applied Cryptography" which describes, analuses, and provides source code for just about every cryptographic algorithm ever heard of. > > On a related note the following statement confuses me, what does > > "Because neither > > of these functions involve encryption, they are believed to be > > exportable from the US and importable into many other countries." Mean?? > > How do they (the sentence refers to Williams insecure function and MD5) > > not encrypt?? If they don't encrypt what do they do, and how does that > > differ from DES?? MD5 produces a cryptographic checksum, but you can't get from the checksum back to the input that produced it. Hence it's not a method of encryption, but a fingerprinting technique that can be used to verify the correctness of some data. Get hold of and read the literature for more information. -- Greg Black To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message