[948] in cryptography@c2.net mail archive
Re: encryption by the wind in an open field
daemon@ATHENA.MIT.EDU (Black Unicorn)
Fri Jun 6 15:46:51 1997
Date: Fri, 6 Jun 1997 14:54:57 -0400 (EDT)
From: Black Unicorn <unicorn@schloss.li>
To: Carl Ellison <cme@cybercash.com>
cc: cryptography@c2.net
In-Reply-To: <3.0.1.32.19970606121411.00bc7190@cybercash.com>
On Fri, 6 Jun 1997, Carl Ellison wrote:
> If two criminals meet in an open field and have a private discussion which
> is not monitored, incriminating information could get lost. It disperses on
> the wind and soon becomes so weak and diffuse that it can no longer be
> decrypted. It's as if it were shredded or mulched (on paper) or subjected
> to a massive transposition cipher with a key that gets lost.
Let's discuss this, without getting into the depths of "if a bit is
encrypted in a lab, but no one has the key, was it ever plaintext?"
mushiness, in terms of active and passive loss of data (evidence).
> If a criminal writes a diary entry for himself including incriminating
> information then deletes it with a good disk wiping program, does the
> lost data differ in any significant way from the dispersed verbal
> communication of the previous paragraph?
Well, the way I look at this is such:
Intent is useless in this analysis. We can hardly start imposing criminal
liability if a criminal speaks with his accessory in an area known for the
quick dispersal qualities of the winds with the intent of preventing the
creation of or collecting evidence.
Instead it becomes important to distingish between failing to create
evidence, and destroying or obfuscating evidence already created.
Legal minds are used to considering evidence in terms of material things.
evidience is almost always something you can put in a bag. The rest is
testomony.
Ciphertexts themselves, bits in the ether, are not evidence, a disk with
ciphertext on it is. Same with the conversation of several mob bosses.
That's not evidence. The tape of it is.
Now, if he creates evidence in the form of a diary, and then destroys it
he is destroying evidence. The conversations remnants lost on the wind
are just a bad analogy. No evidence was ever created.
> If a criminal writes a diary entry for himself including incriminating
> information and encrypts it and then loses the key, does the undecipherable
> ciphertext differ in any significant way from the deleted data
> of the previous paragraph?
If he really loses the key? It's different than the conversation because
something material remains after the fact. It's not much different than
the diary, except that the potential for recovery might be greater than
totally deleted bits.
> If a criminal writes that diary entry and forgets the key, has the key been
> lost? Should attempts be made by coerced hypnosis to recover the key?
Well, the question of coerced hypnosis is a different and constitutional
one. Could he be held in contempt and required to sit in jail until he
produced the key or until the judge was satisified he never will/could? I
think probably so. I think Prof. Froomkin might have written on this
topic at one point or another.
> If a criminal writes that diary entry and claims to have forgotten the key,
> can he be trusted and should the key be treated as lost?
See above.
> If a criminal writes that diary entry and remembers the key but refuses to
> hand it over, is he guilty -- and, if so, of what?
Contempt of court. Destruction of material evidence to a crime.
Obstruction.
Really the leap from a locked safe containing the bookkeeping evidence of
illegal activity, and the encrypted disk is not a great one.
It all hinges on your view of the concept that a court is entitled to
evidence of a crime it is hearing argument on.
> - Carl
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