RFC 3711: The Secure Real-time Transport Protocol (SRTP)

Publisher

IETF / RFC Editor

URL

https://www.rfc-editor.org/rfc/rfc3711.html

Published

2004-03-01

Updated

unknown

Accessed

2026-09-23

HTTP status

200

License

IETF Trust Legal Provisions (BCP 78); no-redistribution; short excerpts and locators only

Source notes citing this source

• For SRTP media captured without keys, sequence-number based loss and timing statistics can still be derived from the clear RTP header, but codec-dependent statistics and audio playback are not available. inferred in context
• In SRTP the encrypted portion is the RTP payload; the RTP header, including sequence number and SSRC, is authenticated but not encrypted. in context
• RFC 3711 makes AES in Segmented Integer Counter Mode (AES-CM) the default SRTP encryption transform. in context
• RFC 3711 makes HMAC-SHA1 the default SRTP message authentication, with an 80-bit authentication tag and a 160-bit session authentication key. in context
• RFC 3711 defaults to a 128-bit SRTP master key, a 112-bit master salt and a key derivation rate of zero, meaning session keys are derived once and not periodically refreshed. in context
• RFC 3711 makes the NULL cipher mandatory to implement alongside AES-CM, which permits SRTP streams that are authenticated but not encrypted. in context
• Under RFC 3711 a single master key may protect at most 2^48 SRTP packets and 2^31 SRTCP packets. in context
• SRTP keeps a 32-bit rollover counter (ROC) that the sender must increment each time the 16-bit RTP sequence number wraps, and the ROC forms part of the packet index used for encryption. in context
• Message authentication is mandatory for SRTCP under RFC 3711. in context
• For SRTP (as opposed to SRTCP), RFC 3711 makes the authentication tag RECOMMENDED rather than mandatory. in context

Cite this source record

APA

WarmTransfer. (2004, March 1). RFC 3711: The Secure Real-time Transport Protocol (SRTP). WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-3711-srtp

BibTeX

@misc{warmtransfer-rfc-3711-srtp,
  title  = {RFC 3711: The Secure Real-time Transport Protocol (SRTP)},
  author = {{WarmTransfer}},
  year   = {2004},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-3711-srtp},
  note   = {IETF / RFC Editor, accessed 2026-09-23}
}