From: frantz@netcom.com (Bill Frantz)
Date: Fri, 23 Aug 1996 05:37:29 +0800
To: cypherpunks@toad.com>
Subject: Re: RC4 RC2 & MD5???
Message-ID: <199608221816.LAA01552@netcom6.netcom.com>
MIME-Version: 1.0
Content-Type: text/plain


At 12:58 PM 8/21/96 -0700, Jeff Davis wrote:
>I assume then that the Netscape encryption is Symetric Key, so how do
>RC4 RC2 and MD5 compare and contast? TIA   

RC2 and RC4 are both both variable key length cyphers developed by Ron
Rivest for RSA Data Security Inc.  They were both protected by trade
secret, but both have been reverse engineered and posted to the net.  Both
of them have fast-path export approval if their key length is 40 bits or
less.

MD5 (Message Digest 5) is not a cypher but a secure hash.  If takes an
input of variable length and computes a 128 bit hash.  Recently some
weaknesses have been found in MD5 leading to the recomendation that new
applications be coded to use SHA1 instead.

As a note: Any good secure hash can be used as a symetric key cypher. 
Usually doing so involves considerably more computation than a symetric
cypher of equal strength.


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