From: frantz@netcom.com (Bill Frantz)
Date: Sun, 20 Oct 1996 22:29:54 -0700 (PDT)
To: C Kuethe <ckuethe@gpu.srv.ualberta.ca>
Subject: Re: Wrap Up: Conference on Law Enforcement and Intelligence
Message-ID: <199610210529.WAA26268@netcom7.netcom.com>
MIME-Version: 1.0
Content-Type: text/plain


At 11:13 PM 10/20/96 -0600, C Kuethe wrote:
>On Sun, 20 Oct 1996, Bill Frantz wrote:
>> (3) The devil is in the details.  I still am not convinced that MacPGP has
>> enough sources of entropy for its IDEA key generation.  (But I am not
>> convinced that it doesn't either.)  I put integrating Jon Callas's entropy
>> manager into MacPGP as a high priority.
>
>Tell me more... I use macpgp.  I just built some new keys tonight, a 2048
>bit monster.  PGP wanted 1496 bits of rand info... where is it's entropy
>"Hole"
>
>And what is the "Entropy Manager"?

When you build RSA keys in PGP it uses keyboard timings to acquire "true
randomness" or entropy.  This kind of randomness is related to quantum
mechanical uncertainty.  It probably has enough entropy to safely generate
RSA keys by the keyboard technique it uses.

In addition to RSA keys, it generates symmetric IDEA keys whenever you send
a message.  It uses keystrokes accumulated during normal operation and
saved in a file called randpool (or something like that) to generate these
keys.  Since you almost never enter keystrokes during the normal operation
of MacPGP, I am concerned that randpool does not have enough entropy.

Entropy Manager is a program Jon Callas of Apple is working on.  It uses
well-known sources of entropy in the computer to build up a pool of entropy
for use by programs that need it.  The last I heard, it was nearly ready. 
I would trust it more than the ported PGP since Jon has examined sources
available in the Macintosh specifically.


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