Privacy-Preserving Equality Test

Many countries around the globe are investing on e-healthcare increasingly, which offers tremendous benefits to all stakeholders in healthcare. Nevertheless, this technology introduces unprecedented privacy concerns toward patients and raise more uncertainty among them to use e-healthcare for monitoring their vital signs. These concerns necessitate finding scientific solutions, which enable e-healthcare systems to process and analyze privacy-sensitive information, and offer services to the patients without violating their privacy. One of the approaches to address the privacy concerns is utilizing cryptographic techniques, which provide us tools to create Privacy-by-Design e-healthcare systems. Moreover, cryptographic solutions allow to process patients’ private information, while they are kept confidential and only known to the patients. Although using cryptographic technique is effective in providing privacy and processing private information, it results in high computational and communicational overhead. In fact, the current cryptographic building-blocks are not efficient enough for processing encrypted data in large-scale databases. In this paper, we address one of the highly used cryptographic building-blocks, which is checking the equality of two encrypted values. We investigate through the performance of the state-of-the-art secure equality tests and propose novel techniques to reduce their costs in terms of computation and communication. Then, through the complexity analysis and experimental results, we show 99% improvements in terms of computation is achieved. These improvements make the e-healthcare systems more attractive in terms of efficiency and in reach of practical applicability.