What is the secure version of the Lightweight Directory Access Protocol (LDAP), using SSL/TLS encryption to prevent eavesdropping and man-in-the-middle attacks?

The correct answer is LDAPS, which stands for Secure Lightweight Directory Access Protocol. LDAPS is an extension of LDAP that incorporates SSL/TLS encryption to secure the transmission of information between clients and directory services. By using encryption, LDAPS effectively protects data in transit, preventing unauthorized interception and tampering by attackers, such as eavesdroppers or participants in a man-in-the-middle attack.

The importance of LDAPS lies in its ability to secure sensitive directory service data, which often includes user authentication credentials and personal information. This security layer ensures that communications are encrypted, thus maintaining confidentiality and integrity.

Other options don't serve the same purpose. OAuth is primarily an authorization framework that allows limited access to user resources without sharing credentials but does not specifically address the secure communication aspect of directory service queries. RADIUS is an authentication, authorization, and accounting protocol used for network access but operates differently from LDAP and does not focus on directory services in the same manner. Diameter is a successor to RADIUS, designed to improve upon it with additional capabilities, but it also does not function as a directory service protocol.