Securing Audio Using Master Key Identifier (MKI)

For secure audio communications, Polycom phones offer support for the crypto header with and without MKI in the offer SDP.

The following optional parameter allows you to include the crypto header in the SDP that uniquely identifies the SRTP stream within an SRTP session. The far end can choose to include a crypto with or without MKI.

Table 1. MKI Parameters

Template

Parameter

Permitted Values

Change Causes Restart or Reboot

sip-interop.cfg

sec.srtp.mki.enabled

1 (default) - The Polycom phone offers two cryptos in the SDP offer: one without an MKI, and one with a four-byte MKI parameter in the SDP message of the SIP INVITE / 200 OK.

0 - Polycom phone offers only one non-MKI crypto in the SDL offer.

No