Lawful interception is the collection of information from communications networks by a person or agency with the legal authority to gather such data. A court order may be necessary to provide legal authority for the interception of private data, although the order can be sealed to prevent the subject of the order from becoming aware of it. This technique is one among a library of options available to law enforcement agencies for the purpose of identifying and addressing criminal activity and collecting information to pursue court cases.
A wide variety of communications can be legally collected with lawful interception techniques, including phone calls, emails, records of Internet traffic, and so forth. Communications systems may be designed with support for lawful interception to make data collection easier, and some companies developing and using such systems voluntarily comply with law enforcement, allowing officers to access data by request rather than with a court order.
The ethics of lawful interception are a topic of debate. Proponents argue that access to communications gives law enforcement evidence useful for criminal cases and can also be helpful for intelligence gathering. Intercepting communications may allow people to identify and act on terrorist plots and other security threats, as well as helping agencies track down information leaks and compromises to confidentiality and security. Being able to keep lawful interception confidential is also viewed as an important component of such programs, as it allows people to listen in on communications without alerting the subject.
Privacy advocates have concerns about lawful interception. Some believe that people can expect a reasonable right to privacy in telecommunications and that subjects of warrants should be informed about the warrants and their scope. Others are concerned about voluntary compliance by telecommunications companies and the potential risks it may pose to people like political dissidents and activists. These individuals are not breaking the law, but could become targets for law enforcement investigations.
Many nations have laws addressing lawful interception and these laws have been adjusted to address changes in the telecommunications industry and the technology used for telecommunications. The widespread advent of cell phone communications, for example, has required changes in methods and practices for data interception. Some of these laws also address privacy concerns, tightening standards for warrants and court orders and mandating secure handling and storage of any information collected to preserve as much privacy as possible for subjects of lawful interception operations.