Comment by carshodev

This makes it non social media, the reason I post on social media is to ALLOW the world to view what I speak about. I don't mind if my data is harvested or trained off of.

Posting with encrypted data makes no sense as you are disrupting the social network with worthless garbage for 99.999% instead it would just be better to have an RSS type feed that your consumers (friends) can subscribe to and it shows the comment you made and the link to what you commented on.

Or if you just want to say something about it to 1 friend just send it to them.

You could still have pub/priv keys and an autodecrypt system though or use traditional authentication for allowing content pulls.