There are three things I want from an alternative: 1) Decentralized, preferably democratic-by-the-users, control. No centralized server where everything is ke

There are three things I want from an alternative: 1) Decentralized, preferably democratic-by-the-users, control. No centralized server where everything is kept in plaintext. 2) Privacy. I share what I want, and only that. People with whom I don't connect don't know I exist. 3) Authentication. My online identity is unique to something about me that exists in meatspace. Whom I connect with can be restricted to people I know in meatspace. Note that this is the opposite of our normal standard of anonymity: 4chan can be as anonymous as it likes, but a social network for groups of friends ought to prevent anonymous trolls or ads from flooding into my feed. Basically, I want a social network on which I own and control my own info, and on which I keep my IRL identity strictly separated from, for instance, the anime avatar I pretended to be on various bulletin boards. Do any existing alternative social networks meet these criteria?