[Sjlver]

Alas, psst can't help with that. With psst (or indeed any secret sharing scheme), there is a single secret which is only split while at rest. In order to actually make use of the secret, it needs to be recovered from the shares.

Your use-case would probably use other techniques, such as multi-signature schemes, multiparty computation, and zero knowledge proofs. Decentralized identity management is a difficult problem.