spying

Spying is the act of gathering information about a person, organization, or government without their knowledge or consent. In contemporary discourse, spying is often synonymous with espionage, especially when carried out by a state against another state, but it can also refer to corporate or individual intelligence activities. The information sought may concern military plans, political intentions, economic data, or security vulnerabilities.

Common methods include human intelligence (HUMINT), where undercover agents or informants obtain information; signals intelligence (SIGINT), which involves intercepting communications; imagery and geospatial intelligence to observe targets; and cyber espionage, which uses malware, intrusions, and data exfiltration. Open-source intelligence (OSINT) relies on publicly available information. Espionage operations are often designed to avoid detection and to protect sources and methods.

Historically, spying has played a pivotal role in conflicts and diplomacy. States have organized espionage services since antiquity, and the 20th century saw major counterintelligence and spy networks, such as the Cambridge Five and various WWII and Cold War operations. While espionage can provide strategic advantages, it also risks escalation and legal repercussions when discovered.

Legal regimes governing spying vary by country. Many jurisdictions prohibit unauthorized spying and restrict intelligence activities to authorized agencies subject to oversight, but enforcement and safeguards differ. Ethical debates focus on privacy, sovereignty, and the balance between security and civil liberties. Counterintelligence efforts, cybersecurity measures, and legal remedies are used to detect and deter spying by rivals and criminals.