Banning open source software is probably not feasible (you can distribute the code as a printed book after all). They would have to:

- ban all Internet traffic that uses non-backdoored encryption (all ISPs would be required to report it)

- ban all amateur radio equipment, including all products one could use to build a satellite dish (like aluminium foil?..); keep a fleet of radio-direction-finding vans circling the streets

Eventually, maybe also ban general-purpose non-backdoored computers.