We need a new Katz!

Bruce Schneir writes: « Our protections against police abuse have been severely watered down. The courts have ruled that the police can search your data without a warrant, as long as others hold that data. If the police want to read the e-mail on your computer, they need a warrant; but they don't need one to read it from the backup tapes at your ISP” and that “just as the Supreme Court eventually ruled that tapping a telephone was a Fourth Amendment search, requiring a warrant -- even though it occurred at the phone company switching office and not in the target's home or office -- the Supreme Court must recognize that reading personal e-mail at an ISP is no different.”

The Supreme Court would then reconciliate somehow these two famous statements: the Fourth amendment protects people, not place” (Katz v. United States), but “ the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities, even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third party will not be betrayed.” (US v. Miller).

In US v. Miller, the respondent, relying on Katz, claimed that he had a Fourth Amendment interest in the records kept by his banks because they were merely copies of personal records that were made available to the banks for a limited purpose and in which he has a reasonable expectation of privacy. The Supreme Court argued that the Katz Court had stressed that "[w]hat a person knowingly exposes to the public . . . is not a subject of Fourth Amendment protection."

So we have these concepts, "copies", "limited purposes", "exposing knowingly to the public"…
In Miller, the Court noted that “checks are not confidential communications but negotiable instruments to be used in commercial transactions.” But our data, even though they are becoming a commercial commodity more and more every day, may be still confidential, if we treat them that way.

Our email could be considered copies of a confidential message sent to us, made available to our ISP for the limited purpose of storing it so we can access it later and read it on our private computer. We would then be in charge of storing that private message, in our own hard drive., protected by the Fourth Amendment. Well, what if we use web mail, what if our company is cloud computing? Should users of Outlook be more protected than the ones using, say Gmail?