From: yanek@novavax.nova.edu (Yanek Martinson)
Date: Mon, 30 Nov 92 17:41:25 PST
To: wcs@anchor.ho.att.com  (Bill Stewart)
Subject: Re: Unlabelled PGP messages
In-Reply-To: <9211302245.AA04980@anchor.ho.att.com>
Message-ID: <9212010141.AA18205@novavax.nova.edu>
MIME-Version: 1.0
Content-Type: text/plain


[talks about posting anonymous messages that only recipient can decrypt]

> 	like a 4-bit checksum of the PGP key or the key length as a label 
> 	- it's not enough to identify which key it is, but it's enough
> 	to cut down on your decryption by a factor of 16.
> 	A longer checksum is too revealing - even 8 bits identifies 
> 	1/256th of the crypto community, which isn't very anonymous.

Why not generate a key just for this conversation, and then post a full
128-bit (22 base64 characters) hash in the subject.

You can even have a key for each message if the conconversation is two-way
then whenever you are about to send a message you can generate a new key
pair and include the new public key with your message.  

As soon as you receive and decrypt the message for that key, destroy the
private key.