We are running CCM 4.1(3). Someone from Network Team found out that it's possible to capture Voice packets using sniffer tools like Observer, Ethereal etc & they were able to recreate the Voice packets & snoop in on the conversation. Is it possible to encrypt the RTP streams?
Haha looks like rob beat me to the punch! Yes as Rob posted above it is possible for H323 configurations. Like I said I did not roll out it to mass production so I really cant speak for the load that the Pub may be under. Seeing that you are in a 1 ccm environment, and everything else that that box is doing (moh,conferencing,ect...) that may be something to watch for.
Glad to hear things are going better for you! Here is the similar doc for H.323;
Media and Signaling Authentication and Encryption Feature for Cisco IOS H.323 Gateways
We did get the ES from Cisco so we are trying the upgrade again this Saturday :)
Hope this helps!