We enable users to prove that they participated in a clinical trial / study without the conducting service or company (RH) being aware of the "crypto" aspect of their user identity. On the other hand, the prover (us) shouldn't learn anything about the actual user. Welshare's protocol also neither publicy correlates any user ids or personally idenitifiable information.
To enable this blindfolded proof issuance, we require minimal action on the service company's (RH) side. To initiate the proof creation process, they must be able to
- identify one user by an unique identifier (UID) that can be unique for a trial instance
- store a random array of bytes ("nonce") per user, ideally using a crypograpically sufficiently safe RNG. The nonce helps deidentifying the user
- display the UID & the indidual nonce to the user / allow them to request it
- invite study participants by their preferred means of communication to a decentralized web application, hosted by welshare