Hello Tim, On 02/04/2013 03:58 PM, McLeod, Tim wrote: > Attempting to use/modify pjsip user agent such that it uses SRTP. To obtain the key for the SRTP session it is necessary to negotiate with the remote endpoint. We think that a single message/response negotiation would be straightforward since we could simply rely on the call set-up messages. However, the negotiation we are required to use is a double message/response conversation, i.e.: > > I_MESSAGE1 > R_MESSAGE1 > I_MESSAGE2 > R_MESSAGE2 > > Has anyone any experience of using pjsip for this type of key/call negotiation? Unfortunately we are under extremely tight time constraints, literally just a couple of days to resolve this! > PJSIP already supports SRTP. The key exchange occurs in a single round-trip. If you need multiple round-trips for the key-exchange as your message implies, consider adapting and implementing something like RFC #4567. This is of course heavily RTSP-oriented, but you can still adapt that solution to fit into the SIP-Ecosystem. I can assist your Engineers and/or implement that for you in a fully SIP compliant manner using PJSIP. Best Regards, Alain Totouom > Tim McLeod MBCS CITP > Principal Engineer > Tel: +44 1633 715097 > Mob: +44 7765 088364 > Email: tim.mcleod at cassidian.com<mailto:tim.mcleod at cassidian.com> > RLI: tim.mcleod at eads.r.mil.uk<mailto:tim.mcleod at eads.r.mil.uk> > Website: www.cassidian.com<http://www.cassidian.com/> -- "" (o)(o) ___o00o__(__)__o00o_____ 1024D/A9F85A52 2000-01-18 Dipl.-Ing. Alain Totouom <totouom at gmx.de> PGP Fingerprint DA18 0DF2 FBD2 5F67 0656 452D E3A2 7531 A9F8 5A52 3072D/146D10DE 2011-09-29 Dipl.-Ing. Alain Totouom <totouom at gmx.de> PGP Fingerprint 39A4 F092 FFA7 C746 CC30 5CB0 6909 1911 146D 10DE
