Secure Cell / Mobile Phone Comms

I am looking for a generic piece of Java software that will work on both Motorola and Nokia phones, that can be used to encrypt voice comms simply. The software needs to run in the background constantly, I am guessing, and when a call comes through it needs to determine whether it is a secure call or not. The level of encryption and the key, whether AES etc, needs to be chooseable by the user. Keys should be use once only and regenerated at every new call.