Various government subjects wrote:
eg: Laws in US forbid use of encrypted radio
Traditional spread spectrum seem rather off the shelf and wouldn't really consider encrypted as such. What I mentioned *is* encrypted, both at the RF layer itself, and at the data layer riding on top. It's also really hard to locate random background noise (power). Even if, since random noise can't be proven to be crypto, it can't be shut down due to any crypto reason, insufficient cause. Nor do guerrilla radios care about such laws.
In the US hams can encrypt under exactly one specified circumstance: Control of a space station, meaning a radio station on a satellite. That is presumably to keep "outsiders" from taking over control.
The history of any such takeovers, classified or otherwise, would be interesting read.