Final answer:
TLS/SSL and Kerberos are authentication protocols that can be encrypted but are not necessarily encrypted by default.
Step-by-step explanation:
As an authentication protocol, TLS/SSL can be encrypted, but are not necessarily encrypted by default. TLS/SSL (Transport Layer Security/Secure Sockets Layer) is a protocol that provides secure communication between a client and a server. It ensures data confidentiality, integrity, and authentication.
For example, when visiting a website with HTTPS, the data exchanged between your browser and the website is encrypted using TLS/SSL. However, not all authentication protocols are encrypted by default. One such protocol is Kerberos, which uses encryption for authentication but not for data transmission.