# SRTP
> Secure Real-time Transport Protocol – encrypts voice and video media in VoIP calls

SRTP encrypts VoIP media streams, protecting voice and video from eavesdropping.

## What is SRTP?
Secure Real-time Transport Protocol (SRTP) is an extension of [RTP](/voip-glossary/rtp/) that adds confidentiality, message authentication, and replay protection to voice and video streams. It encrypts the media payload so that even if packets are intercepted, the content cannot be understood.

## SRTP and TLS
SRTP protects the media plane while [TLS](/voip-glossary/tls/) protects the signaling plane ([SIP](/voip-glossary/sip/) messages). Together, they provide end-to-end encryption for VoIP calls. For maximum security, [ZRTP](/voip-glossary/zrtp/) can negotiate keys without relying on the signaling path.

## Related Terms
- [RTP](/voip-glossary/rtp/)
- [TLS](/voip-glossary/tls/)
- [ZRTP](/voip-glossary/zrtp/)