Shared this on the CAP-COMM mailing list too, but for those of you not subscribed to it, here's a really good video lecture on P25 and encryption and potential shortfalls: A Security Analysis of the APCO Project 25 Two-Way Radio System (http://www.youtube.com/watch?v=NW-jRRTPCuw#ws)
Thanks Brad.
I find this type of thing fascinating, especially the human-factors.
Textbook errors in mode confusion, lack of feedback, false sense of security, unintended consequences, etc...