We are building a healthcare app and need to handle patient records without a central database. How does a Web3 & Blockchain approach to Self-Sovereign Identity (SSI) work in practice? We want users to own their data using DIDs and Verifiable Credentials while still being able to share it with doctors securely and privately.
3 answers
This is where Zero-Knowledge Proofs (ZKPs) become essential. You can allow a patient to prove they have a certain medical condition or a valid insurance policy without actually revealing the underlying raw data to the blockchain. In several projects I worked on during 2024, we used the W3C standard for Decentralized Identifiers (DIDs). This Web3 & Blockchain strategy ensures that even if the app's frontend is compromised, the patient's sensitive health records remain encrypted and under their exclusive control via their private keys, which is a massive upgrade over traditional centralized systems.
How do you plan to handle the "key recovery" process for patients who might lose access to their mobile wallets but still need to access their vital medical records?
IPFS is your best friend here. Store the encrypted records there and only keep the hash and the DID reference on the actual blockchain to save on costs.
I agree with Mark; keeping the heavy data off-chain while maintaining the integrity on-chain is the only scalable way to handle large medical files.
Ryan, that is a tough one. We are looking into social recovery through trusted "guardians" like family members or primary care physicians. Another option is using multi-party computation (MPC) to split the key into multiple shards. This way, the patient doesn't have a single point of failure. It’s a balance between making the system truly decentralized and making it usable for people who aren't tech-savvy enough to manage a 24-word seed phrase securely.