For a uniquonym to work, it is necessary for there to be some tie back to ensuring a person can't just create a new one. This requires some kind of way to identify a unique person that is hard to double up. I'll make some separate posts going deeper on this.

Next, it requires a way to prove that within a namespace, that a real identity has no more than one pseudonym linking to it - but without revealing the real identities to anyone. There are a range of different trade-offs here - a topic for another post.