1. A mobile wireless communications device comprising: a wireless transceiver; a series of processing modules; a shared memory connected to said processing modules and to said wireless transceiver; a memory manager module for generating data location indices for data stored in said shared memory; said processing modules cooperating with said shared memory and said memory manager module so that an upstream processing module stores given data in said shared memory and so that a downstream processing module receives the data location index for the stored given data and processes the stored given data based thereon; and a security module for selectively purging data from said shared memory based upon a change in an encryption level of the data.