From 536c76cbb863bab152f19842ab88772c01e922c7 Mon Sep 17 00:00:00 2001 From: ryker <> Date: Mon, 5 Oct 1998 20:13:15 +0000 Subject: Import of SSLeay-0.9.0b with RSA and IDEA stubbed + OpenBSD build functionality for shared libs. Note that routines such as sslv2_init and friends that use RSA will not work due to lack of RSA in this library. Needs documentation and help from ports for easy upgrade to full functionality where legally possible. --- src/lib/libcrypto/dh/generate | 65 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 src/lib/libcrypto/dh/generate (limited to 'src/lib/libcrypto/dh/generate') diff --git a/src/lib/libcrypto/dh/generate b/src/lib/libcrypto/dh/generate new file mode 100644 index 0000000000..5d407231df --- /dev/null +++ b/src/lib/libcrypto/dh/generate @@ -0,0 +1,65 @@ +From: stewarts@ix.netcom.com (Bill Stewart) +Newsgroups: sci.crypt +Subject: Re: Diffie-Hellman key exchange +Date: Wed, 11 Oct 1995 23:08:28 GMT +Organization: Freelance Information Architect +Lines: 32 +Message-ID: <45hir2$7l8@ixnews7.ix.netcom.com> +References: <458rhn$76m$1@mhadf.production.compuserve.com> +NNTP-Posting-Host: ix-pl4-16.ix.netcom.com +X-NETCOM-Date: Wed Oct 11 4:09:22 PM PDT 1995 +X-Newsreader: Forte Free Agent 1.0.82 + +Kent Briggs <72124.3234@CompuServe.COM> wrote: + +>I have a copy of the 1976 IEEE article describing the +>Diffie-Hellman public key exchange algorithm: y=a^x mod q. I'm +>looking for sources that give examples of secure a,q pairs and +>possible some source code that I could examine. + +q should be prime, and ideally should be a "strong prime", +which means it's of the form 2n+1 where n is also prime. +q also needs to be long enough to prevent the attacks LaMacchia and +Odlyzko described (some variant on a factoring attack which generates +a large pile of simultaneous equations and then solves them); +long enough is about the same size as factoring, so 512 bits may not +be secure enough for most applications. (The 192 bits used by +"secure NFS" was certainly not long enough.) + +a should be a generator for q, which means it needs to be +relatively prime to q-1. Usually a small prime like 2, 3 or 5 will +work. + +.... + +Date: Tue, 26 Sep 1995 13:52:36 MST +From: "Richard Schroeppel" +To: karn +Cc: ho@cs.arizona.edu +Subject: random large primes + +Since your prime is really random, proving it is hard. +My personal limit on rigorously proved primes is ~350 digits. +If you really want a proof, we should talk to Francois Morain, +or the Australian group. + +If you want 2 to be a generator (mod P), then you need it +to be a non-square. If (P-1)/2 is also prime, then +non-square == primitive-root for bases << P. + +In the case at hand, this means 2 is a generator iff P = 11 (mod 24). +If you want this, you should restrict your sieve accordingly. + +3 is a generator iff P = 5 (mod 12). + +5 is a generator iff P = 3 or 7 (mod 10). + +2 is perfectly usable as a base even if it's a non-generator, since +it still covers half the space of possible residues. And an +eavesdropper can always determine the low-bit of your exponent for +a generator anyway. + +Rich rcs@cs.arizona.edu + + + -- cgit v1.2.3-55-g6feb