Design communications that leave no trace?

(I'm so chatty lately... sorry...)

While reading a post of Ernie Miller's on the interesting issues posed to open source by the Grokster decision ("Grokster and Open Source: Will Open Source Force the Court to Confront Sony?"), I realized what we really need is a device through which you can communicate which leaves no record. This way, you could speak candidly about the design considerations of your tech-to-be. How could one ensure that such a device's communications would be un-capturable?

(In fact, this raises some other issues... like the fact that fundamental to innovation and business is the ability to deliberate on issues of design and strategy. So we need a way to deliberate in confidence. Of course, if you yourself are the sole product designer, you don't have to send yourself emails (although we all do), which would be subpoenable.)

UPDATE [2005-06-28 23:37:56]: Ping points to Off-the-Record Messaging developed by Nikita Borisov and Ian Goldberg which provides for:

Off-the-Record (OTR) Messaging allows you to have private conversations over instant messaging by providing: Encryption, Authentication, Deniability and Perfect forward secrecy.