Anton's Test of Service Sovereignty:
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If any of follow is true, the service is not fit for sovereign individual.
- Can they shut it's servers? Will it break the service?
- Can they jail CEO or developers? Will it break the service?
- Has the service means to censor you if they are asked to?
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Signal won't pass this test. ProtonMail won't as well. So get yourself ready, they will come for them soon.