I don't think many people are on Signal but it's the most secure, and made by the team who invented the same e2e protocol that WhatsApp uses (also Messenger, Skype and Allo, but it's not on by default, which is the key)
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I don't think many people are on Signal but it's the most secure, and made by the team who invented the same e2e protocol that WhatsApp uses (also Messenger, Skype and Allo, but it's not on by default, which is the key)