Cisco WRP400-G1 Administration Guide - Page 54

Secure Call Implementation 3 Secure Call Implementation This section describes secure call implementation with the WRP400 . It includes the following topics: • "Enabling Secure Calls" section on page 52 • "Secure Call Details" section on page 53 • "Using a Mini-Certificate" section on page 54 • "Generating a Mini Certificate" section on page 55 NOTE This is an advanced topic meant for experience installers. Also see the Provisioning Guide at the following URL: www.cisco.com/en/US/docs/voice_ip_comm/csbpvga/ata/provisioning/guide/ Cisco_Small_Business_IP_Telephony_Provisioning_Guide.pdf Enabling Secure Calls A secure call is established in two stages. The first stage is no different from normal call setup. The second stage starts after the call is established in the normal way with both sides ready to stream RTP packets. In the second stage, the two parties exchange information to determine if the current call can switch over to the secure mode. The information is transported by base64 encoding embedded in the message body of SIP INFO requests, and responses using a proprietary format. If the second stage is successful, the WRP400 plays a special Secure Call Indication Tone for a short time to indicate to both parties that the call is secured and that RTP traffic in both directions is being encrypted. If the user has a phone that supports call waiting caller ID (CIDCW) and that service is enabled, the CID will be updated with the information extracted from the Mini-Certificate received from the remote party. The Name field of the CID will be prepended with a '$' symbol. Both parties can verify the name and number to ensure the identity of the remote party. Cisco Small Business WRP400 Administration Guide 52