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1996-05-02 - Re: [Fwd: Cylink can export 128-bit DH?]

Header Data

From: “Perry E. Metzger” <perry@piermont.com>
To: mpd@netcom.com (Mike Duvos)
Message Hash: b6c82c6cfe1333ce9fe025eca842020d60de4e55ccd7aab5a255f20d60eecdc5
Message ID: <199605021252.IAA20759@jekyll.piermont.com>
Reply To: <199605012312.QAA11109@netcom14.netcom.com>
UTC Datetime: 1996-05-02 19:26:34 UTC
Raw Date: Fri, 3 May 1996 03:26:34 +0800

Raw message

From: "Perry E. Metzger" <perry@piermont.com>
Date: Fri, 3 May 1996 03:26:34 +0800
To: mpd@netcom.com (Mike Duvos)
Subject: Re: [Fwd: Cylink can export 128-bit DH?]
In-Reply-To: <199605012312.QAA11109@netcom14.netcom.com>
Message-ID: <199605021252.IAA20759@jekyll.piermont.com>
MIME-Version: 1.0
Content-Type: text/plain



Mike Duvos writes:
> frantz@netcom.com (Bill Frantz) writes:
> 
>  > Most cryptographic experts recommend Triple DES, encrypting
>  > the data 3 times with 3 different keys.
> 
> It's actually encrypted three times with two keys comprising
> 112 bits of keyspace, using a decrypt on one key sandwiched
> between two encrypts using the other.  This prevents a "man
> in the middle" attack, which would be possible if only two
> DES encryptions were used, one for each key.

Many 3DES implementations actually do use 3 different
keys. Surprisingly, the strength of 3DES with 3 keys is around the
strength you would naively expect 3DES with 2 keys to have, and 3DES
with 2 keys is slightly weaker than you would expect...

.pm

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