From: Phil Karn <karn@qualcomm.com>
Date: Tue, 6 Sep 94 11:04:52 PDT
To: cypherpunks@toad.com
Subject: Re: How to find a primitive root of unity, for Diffe-Hellman?
In-Reply-To: <199409052037.AA04009@xtropia>
Message-ID: <199409061803.LAA08116@servo.qualcomm.com>
MIME-Version: 1.0
Content-Type: text/plain


Maybe I can save you some trouble. Here is a "strong" 1024-bit prime
and generator that I've been using for Diffie Hellman key exchange to
set up keys for IP packet encryption. 

For a "strong" prime p, (p-1)/2 is also prime. This is thought to make
the discrete logarithm problem maximally hard. --Phil

a4788e2184b8d68bfe02690e4dbe485b17a80bc5f21d680f1a8413139734f7f2b0db4e25375
0018aad9e86d49b6004bbbcf051f52fcb66d0c5fca63fbfe634173485bbbf7642e9df9c74b8
5b6855e94213b8c2d89162abeff43424350e96be41edd42de99a6961638c1dac598bc90da06
9b50c414d8eb8652adcff4a270d567f

Generator = 5

You're welcome to verify that this is indeed a strong prime; this should
be considerably faster than searching for one from scratch.

Phil