As I've previously written, what I consider a key flaw in current analysis of Fourth Amendment (and Electronic Communications Privacy Act) protections against interception of Internet communication is that it takes a narrow view of what constitutes communication on the Internet. The standard is "any information" that concerns the substance, meaning, or purport of a communication.

We should look to other forms of communication to arrive at a reasonable definition of Internet communication. I've suggested voice as the most pervasive. We don't permit the recording of waveforms of speech and only exclude transcripts. Without a warrant, the government may not record a telephone conversation.

When a person sends an email message, that form of communication is chosen, for whatever reason, over a telephone call. While the propagation of sound is required for meaningful oral communication by telephone, the propagation of properly formatted SMTP commands and RFC 822 message bodies are required for comprehension of the stream of bytes comprising an email message. Without that formatting, there is no substance, purport, or meaning of an email. In many cases, it won't be delivered at all.

The SMTP commands that transport a message across the Internet are, therefore, comparable to the use of voice to communicate across a telephone line. The courts and the Congress don't allow the recording of the electrical underpinnings that make up that voice communication. It makes little sense to allow recording of the commands and formatting that make up an email message.

If I can get to a point where I can substantively establish this, it becomes clear that what follows is protection of the application layer.

I wrote my law school note on this kind of thing. I technically excluded email from the analysis, but I wrote a lot about how contents of communications at the application layer should be protected. If you get a chance to read it, I'd be curious to know what you think.

It's here.

It's in my pile of papers. I haven't looked at in several months, however, so I can't rattle off the top of my head what I thought. What I recall from my last read of it is that your technical analyses were far more complete and correct than any of the others in my stack. So many of the papers in this realm are so wildly inaccurate technically, it drives me nuts. I may send more in a backchannel in the next couple of days.