SRTP is an extension of the Real-Time Transport Protocol (RTP) that provides enhanced security to audio and video communication. RTP is widely used for Voice over IP (VoIP) as well as audio and video streaming provided by applications such as Skype, Google Hangouts, YouTube Live, and Webex.

While RTP allows for real-time transmission of audio and video, it lacks security measures, exposing the transmitted data to potential eavesdropping or tampering. SRTP fills in this gap by adding encryption, message authentication, and replay protection.


SRTP uses Advanced Encryption Standard (AES) with a 128-bit key length in order to encrypt the RTP payloads. This ensures that your communication data remains private and shielded from unauthorized access.

Message Authentication

Message authentication, also known as data integrity, ensures that the messages you send are not tampered with during transmission. SRTP utilizes HMAC-SHA1 to detect any changes made to the original message, guaranteeing that the receiver can trust the authenticity of the message.

Replay Protection

Replay protection is implemented in SRTP to prevent attackers from re-sending previously captured SRTP packets. This is achieved by checking sequence numbers and maintaining a replay list, allowing the protocol to drop packets that are recognized as duplicates.


As a result, SRTP provides an added layer of security while maintaining the real-time capabilities of RTP. Combining these security features, SRTP has become the preferred protocol in audio and video communication for various applications that require a higher level of security and privacy. Implementing secure protocols such as SRTP is an essential step in enhancing your overall cybersecurity.