The description mentions "ring" signatures, where are they?

[SaleProperly]

I don't see how to perform any signer ambiguous signature scheme from the library. Is this implemented?

[enzoh]

No, unfortunately, I never got around to wrapping up the implementation. If you submit a PR, then I will gladly review it. It should not be too difficult to implement. type RingSignature = []Element with the details described here in section 5.2. You can access that isomorphism ψ from the Pairing internals. I think everything else should be pretty straight forward.