What type of key is used to protect traffic on a circuit?

A Traffic Encryption Key (TEK) is specifically designed to protect the confidentiality of communications on a circuit. It encrypts the data being transmitted, ensuring that it cannot be easily intercepted or understood by unauthorized parties. The TEK is part of a broader framework used in secure communications, where maintaining the integrity and confidentiality of sensitive information is of utmost importance.

The TEK generates unique keys for specific sessions, which enhances security by ensuring that even if one key is compromised, it does not affect the security of future communications. This dynamic keying approach makes TEKs essential in secure communication protocols.

In contrast, other key types mentioned do not serve the same focused purpose or may not exist within the standard COMSEC terminology, which emphasizes the importance of using designated keys for specific functions within secure communication practices. Therefore, selecting the TEK as the type of key used to protect traffic on a circuit reflects a clear understanding of its critical role in maintaining the security of sensitive data during transmission.