Re: The Halting Problem

> The revelation here
> (for me, anyway) is that if arbitrary crypto were made illegal, the
> burden of proof would be on the prosecution which would have to crack
> the message (at least partially).

I believe the burden would actually be on them to crack the message
entirely. Otherwise, you are applying arbitrary algorithms to what may
be a random stream. If you get something comprehensible out, you have
either partially cracked the message, or run into the British Museum
problem (AKA 100 monkeys with typewriters).

This is all very nice.  But if the government can get away with
outlawing crypto, it's a simple matter for them to outlaw any stream
of data they can't read or don't like.  And who says that the burden
of proof will remain on them?  Think about RICO.  You're not
necessarily dealing with rational, technically aware people.  You're
dealing with law enforcement, judges, and juries.

Is this paranoia?  Maybe.  There was recently a series of stories on
RISKS recently about people who had warrants issued and their houses
entered on the basis of unusual electrical consumption or heat output.
Yes, people were monitoring these things.  Do you not think that if
crypto were outlawed, that they couldn't get a warrant to enter your
house or office based on unidentifiable or suspicious data coming out
of it?  And even if they couldn't prove anything, you still need to
convince them to give back your computer and every other piece of
digital equipment they confiscated.

Steganography is useful to keep them from noticing you.  But it's
still low-bandwidth, because unless you're in the business of
distributing video, you're going to look really strange sending
megabytes of gif's over and over again to the same strange addresses
(anonymous remailers).  Once they do notice you, you're going to have
to be a lot more careful.  

I see steganography to be useful in sending short messages, once
codewords, etc. have been agreed upon out-of-band.  It's just not
useful for anything like the cypherpunks mailing list, or even for
personal messages unless it is used sparingly.

		Marc