Pen Register - USA-PATRIOT Act

USA-PATRIOT Act

Section 216 of the 2001 USA PATRIOT Act expanded the definition of a pen register to include devices or programs that provide an analogous function with internet communications. Prior to the Patriot Act, it was unclear whether or not the definition of a pen register, which included very specific telephone terminology, could apply to internet communications. Most courts and law enforcement personnel operated under the assumption that it did, however the Clinton administration had begun to work on legislation to make that clear, and one magistrate judge in California did rule that the language was too telephone-specific to apply to Internet surveillance.

The Pen Register Statute is a privacy act. As there is no constitutional protection for information divulged to a third party under the Supreme Court's expectation of privacy test, and the routing information for phone and internet communications are divulged to the company providing the communication, the absence or inapplicability of the statute would leave the routing information for those communications completely unprotected from government surveillance.

The government also has an interest in making sure the Pen Register Act exists and applies to internet communications. Without the Act, they cannot compel service providers to give them records or do internet surveillance with their own equipment or software, and the law enforcement agency, which may not have very good technological capabilities, will have to do the surveillance itself at its own cost.

Rather than creating new laws regarding Internet surveillance, the Patriot Act simply expanded the definition of a pen register to include computer software programs doing Internet surveillance. While not completely compatible with the technical definition of a pen register device, this was the interpretation that had been used by almost all courts and law enforcement agencies prior to the change.