Which of the following should be used to implement voice encryption?

SSLv3 is a deprecated cryptographic protocol primarily used for securing web traffic (HTTPS) and general transport layer security, not specifically for real-time voice media encryption.

VDSL (Very-high-bit-rate Digital Subscriber Line) is a physical layer technology used for high-speed internet access over telephone lines, having no function in data encryption.

SRTP (Secure Real-time Transport Protocol) is a profile of RTP specifically designed to provide confidentiality, message authentication, and replay protection for real-time data, including voice and video, over IP networks. It uses cryptographic primitives to secure the media stream within a Voice over IP (VoIP) communication.

VoIP (Voice over Internet Protocol) is a general technology for transmitting voice over IP networks; it is not an encryption method itself, although encryption protocols like SRTP are used within VoIP.