I am looking for an online service that would allow people to send an anonymous message, with full encryption (the message would not be stored in plain text on the server) to one of the users. Once they start such a conversation, they would get a unique link (e.g.
/conversations/123-123-123-123-123-abc) which they can access with a password they have set in the first place. On the other side, the user receiving the message can respond and update the conversation in this way.
Ideally, it should be:
- open-source with possibility to self-host it
- allow user sign-up
- allow sending messages from anonymous public users
What services/software like this exist?