PJSIP also supports a ZRTP implementation that negotiates the key data via the media channel and provides a PJSIP transport for this. Already integrated with SIP/SDP to insert optional SDP data. Werner Am 05.02.2013 01:18, schrieb Alain Totouom: > 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/> > > -- ---------------------------------------------- Werner Dittmann Werner.Dittmann at t-online.de Tel +49 173 44 37 659 PGP key: 82EF5E8B
