From: Jim choate <ravage@bga.com>
Date: Tue, 26 Jul 94 06:13:50 PDT
To: hughes@ah.com (Eric Hughes)
Subject: Re: Forward secrecy
In-Reply-To: <9407251923.AA04133@ah.com>
Message-ID: <199407261313.IAA03263@zoom.bga.com>
MIME-Version: 1.0
Content-Type: text


> 
> I agree.  Each public key creates a different encoding, or a different
> language, as it were.  These encodings/languages are all related, but
> mutually incomprehensible.  Encryption software has the capability to
> read any of these languages because it is multi-purpose software.
>
One possible hole here is that since they share a commen algorith then
the algorithm is the 'language' and not the actual messages. This would
mean that you are each using the same language. There is also the aspect
of once discovered you could be charged with obstructing justice which
has very stiff penalties.

> 
> Here, then, is the connection back to the original issue.  The courts
> distinguish between acts of speech (fifth amendment protection) and
> supplying objects, such as a subpoena provide the key to a safety
> deposit box.  As Marc Rotenberg once put it to me, the court cannot
> require you to incriminate yourself, but they can require you to
> participate in your own downfall.  Forward secrecy protects you
> against court order, because you cannot be held in contempt of court
> for not providing something that doesn't exist.  If you destroy your
> keys in a timely fashion, your exposure is limited to the time since
> the last key change.
>
They make you participate by giving you immunity in which case you have no
choice but to reveal it or go to jail. Either way somebody is going to jail.
As to self-incrimination, gee, I thought that was the whole purpose of calling
witnesses and such, either to discredit themselves (which is equivalent to
incriminating oneself if you are the defendant) or to incriminate others (and
here we are back to immunity). 

While it is true you can't be held in contempt of court for not providing 
something that doesn't exist they can get you for destroying evidence.