MediBloc, an open-source healthcare data platform, is leveraging the Qtum blockchain, IPFS, and NuCypher KMS, to create a Patient-controlled electronic Health Records (PHR) system.

MediBloc’s mission is to give the ownership of health information back to patients, allowing the rightful owners of health data to both keep their data private and monetize it in various ways. The MediBloc platform will also incentivize healthcare providers, insurers, researchers, and pharmaceutical companies to participate and contribute to a new blockchain-based ecosystem using Medi Token (MED).

Technical Requirements

One of the key requirements for architecting any PHR platform is ensuring the confidentiality of medical information. Storing unencrypted medical records on IPFS exposes patients to possible repercussions, including social stigma associated with certain medical conditions or financial hardship due to difficulties in securing insurance coverage and loss of employment. Achieving confidentiality of records stored on IPFS — which is, by definition, public — while maintaining the ability to share those records with appropriate medical providers, is a fundamentally difficult problem.

Simply storing encrypting records in IPFS is insufficient as there must be some mechanism to provide access to the patient’s medical provider. In MediBloc, there are three primary actors who require access to private data:

  • Patients — the individuals to which records pertain
  • Healthcare providers — the individuals or entities (doctors, hospitals) that require access to records for medical purposes
  • Data researchers (the individuals or entities wishing to use records for research or to develop healthcare products and services)

Each of these actors has certain read/write privileges, which should ultimately be configurable by the patient.

NuCypher Integration

We can map each actors to their corresponding roles in NuCypher’s proxy re-encryption cryptosystem:

Patients encrypt data client-side under their own encryption keys. They then upload their encrypted records to IPFS for storage. When patients wish to grant access to a healthcare provider or data researcher, they issue re-encryption keys targeting the recipient’s public key to the NuCypher KMS network. The network uses these re-encryption keys to transform the ciphertext in IPFS for the recipient, at which point the recipient is able to decrypt the records with their own private key. If the patient switches medical providers or wishes to revoke access for any reason, they issue a revocation request to the NuCypher KMS network and the relevant re-encryption key is deleted. If the recipient attempts to access the data in IPFS post-revocation, they are unable to decrypt the data.

By leveraging NuCypher’s proxy re-encryption technology, MediBloc is able to create a flexible and powerful patient-controlled EHR that guarantees confidentiality and scales from clinical records of only several megabytes to medical images of a few hundred megabytes to genomics data of several gigabytes.

For additional information on MediBloc, please visit And to learn more about NuCypher KMS, please visit