A Survey on Privacy Concerns in Blockchain Applications and Current Blockchain Solutions to Preserve Data Privacy

Abstract

Due to the offering of many benefits, blockchain is a useful environment to build many applications in multiple fields such as cryptocurrency, Internet of Things (IoT), mobile applications and healthcare industry. However, it has a problem in ensuring the privacy of user data due to its public nature. Data on a blockchain is public and can reveal someone’s personal data or transactions. Many applications that venture in blockchain such as financial applications, Internet of Things (IoT) and healthcare applications can fall victim to revelation of personal data and linking attack. Many solutions such as automated access-control protocol that does not require a third party, a local miner operating in a local private blockchain that enforces users’ access control policy, a cryptographic protocol that lets contractual parties interact by using zero-knowledge proof, and computation of data query in a distributed way by using secure multi-party computation have been proposed to tackle this privacy issue in using blockchain. Hence, this paper provides a review on the current solutions that addresses the privacy issues of blockchain in different platforms. However, these solutions have some limitations that cannot be overlooked and proper measures must be taken to make blockchain to be able to better protect the privacy of its users. This paper also discusses the limitations of the solutions and looks into the aspects that need to be addressed.