From: Hal <hfinney@shell.portal.com>
Date: Sat, 11 Feb 95 17:06:32 PST
To: cypherpunks@toad.com
Subject: Re: Does PGP scale well?
In-Reply-To: <9502112237.AA17845@snark.imsi.com>
Message-ID: <199502120105.RAA20992@jobe.shell.portal.com>
MIME-Version: 1.0
Content-Type: text/plain


I was just reading RFC1034 about DNS, and one thing I noted was that there is a
"reverse lookup" feature.  This allows you to go from, say, 156.151.1.101
to portal.com.  This problem seems similar in some ways to the key lookup
problem since you have a relatively unstructured number and you want to
use it as a lookup key.

According to the RFC, if you want to know what host machine is at
address 156.151.1.101, you do a lookup of 156.151.1.101.IN-ADDR.ARPA.
The RFC did not make it very clear how this is done.  Does this use a
"flat" database?    Is it distributed in some way?  Or has this method
perhaps been superceded by some other?

I can see that the key problem is worse than the reverse lookup problem
because there are many more users than hosts.  Although in the long run
won't everybody have a computer at home that has an IP address?  Will the
nameserver hierarchy run into problems then?  There is no obvious
hierarchical arrangement as we have now with our .edu and .com sites,
unless we go geographical.  This seems analogous to the PEM/RSA key
certificate hierarchy problem.  In any case the reverse lookup problem
seems like it will be difficult then.

Hal