Certified Information Systems Security Professional (CISSP) Practice Exam

The correct choice is SRTP, which stands for Secure Real-time Transport Protocol. SRTP is specifically designed to provide encryption, message authentication, and integrity, as well as replay protection for audio and video streams in real-time communications, such as Voice over Internet Protocol (VoIP) calls. In VoIP communications, data packets often traverse unsecured networks, making them vulnerable to eavesdropping and tampering. SRTP addresses these vulnerabilities by encrypting the data being transmitted, ensuring that only authorized users can listen to the conversation. Additionally, SRTP helps to authenticate the source of the communication, which adds another layer of security against impersonation and man-in-the-middle attacks. The other protocols mentioned do not serve the purpose of securing VoIP communications. For instance, SNMP (Simple Network Management Protocol) is primarily used for network management, SOCKS is an internet protocol that facilitates the routing of network packets between client and server through a proxy server, and SONET (Synchronous Optical Networking) is a standard for optical telecommunications transport but does not focus on securing VoIP communications. Thus, SRTP is the most appropriate and effective choice for protecting VoIP communications.