One Time Reply Blocks (was Re: strengthening remailer protocols)

[Timothy C. May]

At 4:56 PM 9/11/96, Bill Frantz wrote:

>Let me float one more hair-brained idea.  I think Tim May is right in
>saying that the most secure response technique is the one in Blacknet.
>i.e. The response are posted to some public bulletin board, and then Alice
>reads them at her leisure.
>
>I see two problems with this approach:  (1) It doesn't scale well, and (2)
>Alice's reading of the response may be detected.  (I think of the vans in
>Great Britain which listen to the local oscillator frequency of TV sets to
>find what people are watching.)

I agree that message pools have interesting scaling problems. If most
messages are in the same large pool, and lots of people are using pools,
then that pool could become very, very large. However, we are many _years_
away from this situation, and a very large number of _text_ messages (as
opposed to JPEGs) can be put in a few dozen megabytes of pool space. I
contend that many "scaling problems" turn out to be relatively unimportant,
for various reasons.

(And scaling problems should not be a reason not to deploy a simple
system...odds are that other factors will enter long before the system
breaks. The Xanadu people may have worried too much about hypertext
database scaling problems, while the more straightforward HTML/URL
hypertext scheme actually got deployed and changed the playing field
completely.)

There are also likely to be various kinds of pools, thus partly solving the
scaling problem by hierarchies.

(This could worse the traffic analysis--who is reading what--problem, though.)

On the traffic analysis problem, I also think this is overrated as a risk.
The likelihood that the TLAs could figure out which of the messages in
"alt.anonymous.messages" I am actually interested in are small. And there
are PageSat-type distribution systems, @Home-type cable distribution
systems, etc. (My DSS satellite has provisions for a digital feed...it is
reported to be coming soon.)

Reply-blocks are a _clear_ problem, while message pools have various basic
advantages.

I would worry more about scaling when volume is 1000 times what it now is.

(And digital postage solves a lot of scaling problems.)

--Tim May

We got computers, we're tapping phone lines, I know that that ain't allowed.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May              | Crypto Anarchy: encryption, digital money,
tcmay at got.net  408-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA  | knowledge, reputations, information markets,
Higher Power: 2^1,257,787-1 | black markets, collapse of governments.
"National borders aren't even speed bumps on the information superhighway."