Survey paper on Secured Data Retrieval from a distributed database using custom blockchain and Role Base Access Control.

These days, there has been a paradigm shift in the upkeep of Electronic Medical Records (EMRs) in mobile cloud environments. This involves integrating cloud computing with mobile devices to facilitate the transmission of healthcare information between patients and healthcare professionals. With the help of this innovative approach, healthcare may be provided with a high degree of flexibility, minimal overhead costs, and electronic health record access. This new strategy also raises concerns about the security of the networks that enable e-health systems and the privacy of patient data. Finding a solution to efficiently distribute EMRs across mobile users in mobile cloud settings while also upholding the highest security standards is a challenging task. In this paper, explored two different distributed blockchain and cloud frameworks for EMR sharing that combine blockchain technology with a mobile cloud's Decentralised Interplanetary File System (DIFS). Based on the empirical findings, it seems that the idea provides a practical way to protect critical patient data from possible threats and guarantee the dependability of data transfers on mobile clouds. There are notable performance improvements in areas like data privacy protections, minimal network latency, maximum security levels, and lightweight access control when comparing the results of this security analysis and performance assessment to those of earlier data sharing models.