Secure Distributed Medical Record Storage using Blockchain and Emergency Sharing Using Multi-Party Computation

Consuming over 10 percent of gross domestic product (GDP) of most developed nations, the healthcare industry forms an enormous part of a country's economy. With this industry catering to such a large section of the population, each diagnosed case may have varying levels of severity. A robust and fluid system of care naturally causes significant privacy concerns involving patient information. We propose a working model for secure storage of historical medical records of a patient and protected sharing between doctors and hospitals. A medical file is encrypted using a random symmetric key and is stored in a decentralized peer-peer storage system. The random symmetric key is encrypted using the patient's public key and is securely stored in a public blockchain. The patient's private key, along with the hospital's public key, is input into a proxy key generation cryptosystem that uses a Yao's Multiparty Computation Circuit, to produce a re-encryption key. This key can be used to re-encrypt the random symmetric key stored in the Blockchain to give a ciphertext that can further be deciphered using the hospital's private key. Thus, with the decoded random symmetric key in hand, the medical record is retrieved from storage and decrypted for access. The medical record is then forwarded to a specialized doctor for specific treatment. This system is secure and provides the doctor with the patient's medical records on demand with a fast and immutable technique.