Can Decentralized communication be a viable private communication tool for North Korean divergents?

I don’t think this comes as a surprise to anyone, but NK has a freedom of speech problem. If they communicate through their phone provider, it’s safe to say that they’re exposing themselves to the government, as they monitor messages and calls easily. Couldn't they also use decentralized communication tools that leave no traces? They’re private and they should have no problem masking users and their communication.

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