18 U.S.C. § 2510 — Definitions

This section defines terms used throughout this chapter, which governs wiretapping and electronic surveillance. "Wire communication" means any communication carrying the human voice, in whole or in part, sent over wires, cables, or a similar connection between where it starts and where it's received — including through a switching station — as long as a company providing communication services for interstate or foreign commerce owns or operates that connection. "Oral communication" means spoken words said by someone who reasonably expects the communication is private and not being intercepted. It does not include an electronic communication. "State" means any state of the United States, the District of Columbia, Puerto Rico, or any other U.S. territory or possession. "Intercept" means capturing the contents of a wire, electronic, or oral communication — whether by listening or some other method — using any electronic, mechanical, or other device. "Electronic, mechanical, or other device" means any device that could be used to intercept a communication, except for two things: ordinary telephone or telegraph equipment, when it's either supplied to a subscriber by their communications provider and used normally, or supplied by the subscriber themselves and used normally to connect to the service, or used normally by the provider itself or by a law enforcement officer doing their job; and a hearing aid or similar device used only to bring hearing up to normal. "Person" means any employee or agent of the United States, a state, or a political subdivision, and any individual, partnership, association, joint stock company, trust, or corporation. "Investigative or law enforcement officer" means any federal or state officer legally empowered to investigate or arrest people for offenses covered by this chapter, and any attorney authorized to prosecute those offenses. "Contents," for any communication, includes any information about what the communication substantively says or means. "Judge of competent jurisdiction" means a federal district or appeals court judge, or a state judge of general criminal jurisdiction who is authorized by that state's law to approve interception orders. "Communication common carrier" has the meaning given in the Communications Act of 1934. "Aggrieved person" means someone who was a party to an intercepted communication, or someone the interception specifically targeted. "Electronic communication" means any transfer of signs, signals, writing, images, sounds, data, or intelligence sent, in whole or in part, by wire, radio, electromagnetic, photoelectronic, or photooptical means, that affects interstate or foreign commerce. It does not include: a wire or oral communication; a communication sent through a tone-only paging device; a signal from a tracking device, as separately defined in this title; or electronic funds-transfer information stored by a financial institution in its own funds-transfer system. "User" means anyone who uses an electronic communication service and is duly authorized by its provider to do so. "Electronic communications system" means any wire, radio, electromagnetic, photooptical, or photoelectronic equipment used to send wire or electronic communications, plus any computer or related equipment used to store those communications electronically. "Electronic communication service" means any service that gives its users the ability to send or receive wire or electronic communications. "Readily accessible to the general public" means, for a radio communication, that it is not: scrambled or encrypted; sent using modulation techniques whose key technical details are kept secret to protect privacy; carried on a hidden subcarrier or subsidiary signal; sent over a common carrier's communication system, unless it's a tone-only paging message; or sent on certain frequencies set aside by federal communications regulations — except that a two-way voice call on one of those frequencies that isn't reserved for broadcast auxiliary use still counts as readily accessible. "Electronic storage" means either temporary, in-between storage of a wire or electronic communication while it's being sent, or storage of that communication by a communication service purely to keep a backup copy. "Aural transfer" means a transfer that includes the human voice at any point between where it starts and where it's received. "Foreign intelligence information," for the purposes of the provision covering disclosure of such information, means information — whether or not it concerns a U.S. person — that relates to protecting the United States against actual or potential attacks or other hostile acts by a foreign power or its agent, against sabotage or international terrorism by a foreign power or its agent, or against clandestine intelligence activities by a foreign intelligence service or network or its agent; or information about a foreign power or foreign territory that relates to U.S. national defense, U.S. security, or the conduct of U.S. foreign affairs. "Protected computer" has the meaning given in the federal computer fraud and abuse law. "Computer trespasser" means a person who accesses a protected computer without authorization, and therefore has no reasonable expectation of privacy in any communication sent to, through, or from that computer. It does not include someone whom the computer's owner or operator knows has an existing contract giving them access to all or part of that computer.

The record shows that this section was added by Public Law 90–351, title III, § 802, enacted June 19, 1968, and originally published at 82 Stat. 212. The source credit reflects that the section has since been amended seven times: by Public Law 99–508 (1986), Public Law 103–414 (1994), Public Law 104–132 (1996), Public Law 107–56 (2001), Public Law 107–108 (2001), and Public Law 107–273 (2002). This pattern indicates a statute that has been periodically revised over more than three decades to update its definitions as technology and law enforcement practice evolved. Public Law 90–351 is commonly known as the Omnibus Crime Control and Safe Streets Act of 1968, and Title III of that Act is generally understood to be the origin of federal wiretapping and electronic surveillance law. The commonly cited purpose of Title III was to respond to Supreme Court decisions of the mid-1960s recognizing constitutional limits on government eavesdropping, while also establishing a framework under which law enforcement could lawfully intercept wire and oral communications subject to judicial authorization. The definitions section is generally understood to serve as the foundation for that regulatory scheme, giving fixed meaning to terms used throughout the chapter. The specific reasons for the numerous later amendments—such as those responding to the rise of electronic communications, computer networks, and post-2001 national security concerns—are reflected in the source credit's citation to later Public Laws, but the record here does not establish the particular legislative motivations behind each individual amendment.