SDES

SDES (Session Description Protocol Security Descriptions) for Media Streams is a way to negotiate the key for Secure Real-time Transport Protocol. It has been proposed for standardization to the IETF in July 2006 (see .)

SDES (Session Description Protocol Security Descriptions) for Media Streams is a way to negotiate the key for Secure Real-time Transport Protocol. It has been proposed for standardization to the IETF in July 2006 (see .) INVITE sips:*97@ietf.org;user=phone SIP/2.0 Via: SIP/2.0/TLS 172.20.25.100:2049;branch=z9hG4bK-s5kcqq8jqjv3;rport From: "123" ;tag=mogkxsrhm4 To: Call-ID: 3c269247a122-f0ee6wcrvkcq@snom360-000413230A07 CSeq: 1 INVITE Max-Forwards: 70 Contact: ;reg-id=1 User-Agent: snom360/6.2.2 Accept: application/sdp Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, PRACK, MESSAGE, INFO Allow-Events: talk, hold, refer Supported: timer, 100rel, replaces, callerid Session-Expires: 3600;refresher=uas Min-SE: 90 Content-Type: application/sdp Content-Length: 477 v=0 o=root 2071608643 2071608643 IN IP4 172.20.25.100 s=call c=IN IP4 172.20.25.100 t=0 0 m=audio 57676 RTP/SAVP 0 8 9 2 3 18 4 101 a=crypto:1 AES_CM_128_HMAC_SHA1_32 inline:WbTBosdVUZqEb6Htqhn+m3z7wUh4RJVR8nE15GbN a=rtpmap:0 pcmu/8000 a=rtpmap:8 pcma/8000 a=rtpmap:9 g722/8000 a=rtpmap:2 g726-32/8000 a=rtpmap:3 gsm/8000 a=rtpmap:18 g729/8000 a=rtpmap:4 g723/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 a=encryption:optional a=sendrecv The phone receives the answer from the proxy and now there can be a two-way secure call: SIP/2.0 200 Ok Via: SIP/2.0/TLS 172.20.25.100:2049;branch=z9hG4bK-s5kcqq8jqjv3;rport=62401;received=66.31.106.96 From: "123" ;tag=mogkxsrhm4 To: ;tag=237592673 Call-ID: 3c269247a122-f0ee6wcrvkcq@snom360-000413230A07 CSeq: 1 INVITE Contact: Supported: 100rel, replaces Allow-Events: refer Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, PRACK, INFO Accept: application/sdp User-Agent: pbxnsip-PBX/1.5.1 Content-Type: application/sdp Content-Length: 298 v=0 o=- 1996782469 1996782469 IN IP4 203.43.12.32 s=- c=IN IP4 203.43.12.32 t=0 0 m=audio 57076 RTP/SAVP 0 101 a=rtpmap:0 pcmu/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-11 a=crypto:1 AES_CM_128_HMAC_SHA1_32 inline:bmt4MzIzMmYxdnFyaWM3d282dGR5Z3g0c2k5M3Yx a=ptime:20 a=sendrecv ==See also== MIKEY key exchange method ZRTP end-to-end key exchange proposal DTLS-SRTP end-to-end key exchange IETF standard ==References== ==External links== Presentation about different key exchange methods (Microsoft PowerPoint format.)

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