Comlink security really is easy if you have a good hacker or just good programs. Go with 5 comlinks. The first one is hard wired to the second, which is hardwired to the other 3. The first and second have no wireless enabled. Each Comlink is loaded with rating 6 agents running max scan, and IC. The second comlink has a control agent. This agent switches wireless on and off for the 3 comlinks sequentially, every round.
The only way someone can **** with your communications is to get into the first wireless disabled com inside of 1 round. Otherwise he gets disconnected and has to deal with that unpleasantness.
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Keeping your coms secure is even easier. 1 time pads. Generating 1 time pads in incredibly easy and with the massive amount of memory and processing power available in SR there disadvantages are irrelevant.
How do you get a 1 time pad in SR? Lingsoft's. Generate a random language with several trillion characters. Each of which could mean a word, letter, sentence, or even paragraph. Everyone in the party gets a new copy each day and all communications and data between comlinks is automatically using that Lingsoft, which your comlink translates for you so that it has no effect on you.