Communications security (COMSEC) is the prevention of unauthorized access to telecommunications traffic, or to any written information that is transmitted or transferred. There are several COMSEC disciplines, including:
- Cryptographic security - encrypts data and renders it unreadable until the data is decrypted.
- Emission Security - prevents the release or capture of equipment emanations to prevent information from unauthorized interception.
- Physical security - ensures the safety of, and prevents unauthorized access to, a network's cryptographic information, documents and equipment.
- Transmission security - protects unauthorized access when data is physically transferred to prevent issues such as service interruption.