9th Cir. approves of warrantless monitoring of the to/from addresses of e-mail messages and the IP addresses of websites visited under Smith v. Maryland

The Ninth Circuit held Friday in United States v. Forrester, 05-50410 (9th Cir. July 6, 2007), that warrantless monitoring of the to/from addresses of e-mail messages, the IP addresses of websites visited, and the total amount of data transmitted to or from an account is constitutionally indistinguishable from the pen register in Smith v. Maryland:

Neither this nor any other circuit has spoken to the constitutionality of computer surveillance techniques that reveal the to/from addresses of e-mail messages, the IP addresses of websites visited and the total amount of data transmitted to or from an account. We conclude that these surveillance techniques are constitutionally indistinguishable from the use of a pen register that the Court approved in Smith. First, e-mail and Internet users, like the telephone users in Smith, rely on third-party equipment in order to engage in communication. Smith based its holding that telephone users have no expectation of privacy in the numbers they dial on the users’ imputed knowledge that their calls are completed through telephone company switching equipment. 442 U.S. at 742. Analogously, e-mail and Internet users have no expectation of privacy in the to/from addresses of their messages or the IP addresses of the websites they visit because they should know that these messages are sent and these IP addresses are accessed through the equipment of their Internet service provider and other third parties. Communication by both Internet and telephone requires people to “voluntarily turn[] over [information] to third parties.” Id. at 744.

Second, e-mail to/from addresses and IP addresses constitute addressing information and reveal no more about the underlying contents of communication than do phone numbers. When the government learns the phone numbers a person has dialed, it may be able to determine the persons or entities to which the numbers correspond, but it does not know what was said in the actual conversations. Similarly, when the government obtains the to/from addresses of a person’s e-mails or the IP addresses of websites visited, it does not find out the contents of the messages or the particular pages on the websites the person viewed. At best, the government may make educated guesses about what was said in the messages or viewed on the websites based on its knowledge of the e-mail to/from addresses and IP addresses—-but this is no different from speculation about the contents of a phone conversation on the basis of the identity of the person or entity that was dialed. The distinction between mere addressing and more content-rich information drawn by the Court in Smith and Katz is thus preserved, because the computer surveillance techniques at issue here enable only the discovery of addressing information.

The San Francisco Chronicle article is here.