MediChain gives patients ownership of their own medical data. MediChain is a Medical Big-Data Platform. It allows patients to store their own data in a secure way and gives access to specialists anywhere regardless of the payer network or EMR (Electronic Medical Record) used.MediChain is a Medical Big-Data Platform. Our proposed system allows patients to store their own data off-chain in an appropriate geographic domain, and give access to doctors and specialists anywhere, regardless of the payer network or EMR used