OBLIVIOUS RAM (ORAM) FOR SECURE EHR SYSTEMS: PRESERVING ACCESS PATTERN PRIVACY IN CLOUD-BASED HEALTHCARE

Abstract

A major difficulty with the growing use of cloud-based Electronic Health Record (EHR) 
systems is maintaining data security and privacy. While traditional encryption techniques 
protect the confidentiality of data, they are unable to hide access patterns, which could expose 
private medical data. We offer an Oblivious RAM (ORAM) and Attribute-Based Encryption 
(ABE) system to address this issue. This approach allows for fine-grained access control 
(90.8%) while improving security by concealing access patterns. In order to provide privacy 
without sacrificing performance, our architecture combines Path ORAM and Ring ORAM to 
minimize computational complexity and communication overhead by 14.3%. Additionally, we 
use a hybrid on-chain/off-chain storage approach that reduces storage cost by 81.2% by using 
blockchain technology to create immutable access logs and securely off-chain EHR data collection. Performance evaluations suggest that our model outperforms current methods, 
including Blockchain-based Healthcare Systems by Dwivedi et al. (2019) and k-NN 
Homomorphic Encryption by Zheng et al. (2019), achieving higher access control efficiency 
(90.8%), data integrity (99.6%), and scalability improvement (86.1%). In addition to 
preventing inference attacks, the suggested approach guarantees a scalable and effective 
privacy-preserving solution, greatly surpassing previous frameworks in terms of security, 
effectiveness, and adaptability.