All persons who violate the secrecy of letters, or telegraphic or telephonic communications, shall be punished in accordance with the law.

The secrecy of letters and correspondence is derived through litigation from the Fourth Amendment to the United States Constitution.

The secrecy of letters and telegraphic and telephonic communications is inviolable, except in cases of criminal investigation, mobilization and war.

The secrecy of correspondence or literally translated as secrecy of letters, is a fundamental legal principle enshrined in the constitutions of several European countries.

Article 56 of the one adopted under Leonid I. Brezhnev stated, "The private life of the citizen, the secrecy of letters, telephone conversations and telegraph communications are protected by law."

The secrecy of letters, telegrams, telephone communications and all correspondences in whatever form and by whatever means shall be guaranteed; they shall not be censored or delayed except in cases prescribed by law.

As a consequence in jurisdictions with a safeguard on secrecy of letters location data collected from mobile phone networks has a higher level of protection than data collected by vehicle telematics or transport tickets.