🚀 go-pugleaf

mjr@hussar.dco.dec.com (Marcus J. "Will do TCP/IP for clues" Ranum) writes:

>>4)  The nature of encrypted data renders proof of criminal activity difficult.
>>    How do you prove in court that a chunk of data is a message rather than
>>    random noise [...]

>	A more interesting twist to this problem is:

>	How do you prove in court that the chunk of data is a message/evidence
>	of illegal activity, without either a) expecting a jury will just
>	take your word for it, or b) demonstrating that you can break the
>	encryption?

>	It'd be worth one of us going to jail for a few months to know
>for sure that the government could in fact break cryptosystem XX for any
>nontrivial cryptosystem XX.

For that matter, if I was the defendant, and I'd been using some sort of
"one-time pad" (ie a system where the key length is the message length,
and keys are not re-used), I'd have my lawyer demonstrate that *any*
text of the same length as the message could be extracted from the code
by selecting an "appropriate" key. 

That would *guarantee* "reasonable doubt" unless they picked some *real*
dummies for the jury.

So ciphertext generated with a one-time pad *isn't* going to be *usable*
evidence unless they can *prove* what the key was. And if they can do
*that*, they can just as easily get the original plaintext to use as
evidence.

Any legal types care to comment?

-- 
Leonard Erickson		      leonard@qiclab.scn.rain.com
CIS: [70465,203]			 70465.203@compuserve.com
FIDO:   1:105/51	 Leonard.Erickson@f51.n105.z1.fidonet.org
(The CIS & Fido addresses are preferred)