Secure Real-Time Transport Protocol (Srtp) - Yealink CP969 Administrator's Manual

Click Upload File to select and upload the certificate (*.pem and *.cer) from your local
2.
system.

Secure Real-Time Transport Protocol (SRTP)

Secure Real-Time Transport Protocol (SRTP) encrypts the RTP during VoIP phone calls to avoid
interception and eavesdropping. The parties participating in the call must enable SRTP feature
simultaneously. When this feature is enabled on both phones, the type of encryption to utilize
for the session is negotiated between the IP phones. This negotiation process is compliant with
RFC 4568.
When a user places a call on the enabled SRTP phone, the IP phone sends an INVITE message
with the RTP encryption algorithm to the destination phone. As described in
streams may be encrypted using an AES (Advanced Encryption Standard) algorithm.
Example of the RTP encryption algorithm carried in the SDP of the INVITE message:
m=audio 50020 RTP/AVP 118 9 0 8 18 101
a=rtpmap:118 opus/48000/2
a=fmtp:118 sprop-maxcapturerate=48000; maxaveragebitrate=40000;
a=rtpmap:9 G722/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=ptime:20
a=sendrecv
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:NWM5YmZkZDk5YjI1OTg2MDgwOTM5ZjIxNmJkNTY5
a=crypto:2 AES_CM_128_HMAC_SHA1_32 inline:N2M1NmMzZTI2MGFkZjY5YWYzMGE5MWViYTljNzg4
a=crypto:3 F8_128_HMAC_SHA1_80 inline:NjMxYmIzMDIxNGExM2JkYWQxZTMyODQ1MThkYzg0
m=video 50022 RTP/AVP 97 98 99 117
Configuring Security Features
RFC 3711, RTP
709