prezkription

This project is born out of a problem all travelers suffer, sooner or earlier: obtaining medications during a trip can be challenging, specially when exposed to language or cultural barriers.

In order to overcome these challenges, prezkription was born as a tool where Healthcare Professionals can generate privacy-first medical prescriptions.

The medication data is publicly available, as well as the general instructions to allow an easy retrieval of information for both Patient and other Healthcare Professionals. However, the identifiable data is encrypted, but verifiable through the use of zero-knowledge proofs. The final zero-knowledge proof is obtained by signing a message of the encrypted prescriptionId, allowing us for later retrieval of a prescription in a centralized or decentralized storage.

Once the relevant identities and zero-knowledge proof for the prescription are recorded, the Healthcare Professional creates an onchain attestation for the Prescription.

We use Ethereum Attestation Service as a data layer for Prescription generation, storage and retrieval. Anyone can generate a Prescription using our schema, however, only certified Prescriptions will contain a valid zero-knowledge proof, allowing any Provider to confidently fulfill a Prescription without having to trust in the information presented by the user.

Healthcare Professionals can easily share a QR code with an associated URL to provide easy access to the Patient to their Prescriptions.

The Prezkription Attestation contains a PrezkriptionRewardsResolver which gives out rewards after each attestation creation, as well as revokal, which are accounted for whenever a Prescription is filled after successful verification. This Rewards program is small in scope, but demonstrates the capabilities of plugging in DeFi infrastructure into the healthcare business model, or rather, looking into a more sustainable model, where multisig wallets for organizations can cover the medical expenses of individuals.

There are 3 main components for the prezkription protocol, 2 off-chain and 1 onchain.

The privacy component is handled off-chain through the use of cryptography and zero-knowledge proof generation. For this component, prezkription relies in the Semaphore and Bandada projects, where Semaphore Identities, Groups and Proofs are managed through Bandada's APIs and SDK.

The core of the privacy component are the Semaphore Groups "prezkription-identity-table" and the "prezkription-alpha", which are managed with Bandada API + SDK. These allow us to generate the proofs and identities for the users and data.

For the onchain componente, prezkription uses Ethereum Attestation Service as a data-layer for the Prescriptions. We have created a basic Rewards Resolver, which attached to the Prescription Attestation Schema, allows for Rewards payment to users of the protocol, upon Prescription Attestation generation (Healthcare Professional issuing a Prescription) and upon revokal (Healthcare Provider fulfilling a Prescription).

Finally, prezkription uses a small centralized database to keep track of the historical roots of the merkle trees generated with Semaphore, to facilitate the management of the groups: new identities added or removed, as well as the generated proofs.

This sufficiently decentralized approach gives prezkription enough flexibility to experiment with new business models. Our current architecture is web-based, using a NextJS application connected to the relevant off-chain APIs and onchain infrastructure.