Re: [dispatch] Fwd: I-D Action: draft-johnston-dispatch-osrtp-00.txt

"Roni Even" <> Wed, 04 November 2015 04:06 UTC

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From: Roni Even <>
To: 'Alan Johnston' <>,
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Date: Wed, 04 Nov 2015 06:05:56 +0200
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Subject: Re: [dispatch] Fwd: I-D Action: draft-johnston-dispatch-osrtp-00.txt
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In my view this approach contradict section 6.11 of RFC5763


Best Effort Encryption



   [RFC5479] describes a requirement for best-effort encryption where

   SRTP is used and where both endpoints support it and key negotiation

   succeeds, otherwise RTP is used.


   [MMUSIC-SDP] describes a mechanism that can signal both RTP and SRTP

   as an alternative.  This allows an offerer to express a preference

   for SRTP, but RTP is the default and will be understood by endpoints

   that do not understand SRTP or this key exchange mechanism.

   Implementations of this document MUST support [MMUSIC-SDP <> ].



From: dispatch [] On Behalf Of Alan Johnston
Sent: Wednesday, July 08, 2015 2:03 PM
Subject: [dispatch] Fwd: I-D Action: draft-johnston-dispatch-osrtp-00.txt




Many of us have been talking about "Best Effort SRTP" for many years, and there are a number of deployments.  In addition, the IMTC has recommended it, and the SIP Forum would like to recommend it in SIPconnect 2.0 which for the first time includes SRTP media.  With the publication of RFC 7435 (, the IETF has endorsed this approach as Opportunistic Security (OS), so it would be nice to bring standards in line with industry practice.


Comments on the draft, "An Opportunistic Approach for Secure Real-time Transport Protocol (OSRTP)" and the best way forward are most welcome!


- Alan -


---------- Forwarded message ----------
From: <>
Date: Mon, Jul 6, 2015 at 1:48 PM
Subject: I-D Action: draft-johnston-dispatch-osrtp-00.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.

        Title           : An Opportunistic Approach for Secure Real-time Transport Protocol (OSRTP)
        Authors         : Alan Johnston
                          Bernard Aboba
                          Andy Hutton
                          Laura Liess
                          Thomas Stach
        Filename        : draft-johnston-dispatch-osrtp-00.txt
        Pages           : 8
        Date            : 2015-07-06

   Opportunistic Secure Real-time Transport Protocol (OSRTP) allows
   encrypted media to be used in environments where support for
   encryption is not known in advance, and not required.  OSRTP is an
   implementation of Opportunistic Security, as defined in RFC 7435.
   OSRTP does not require advanced SDP extensions or features and is
   fully backwards compatible with existing secure and insecure
   implementations.  OSRTP is not specific to any key management
   technique for SRTP.

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