Survey of Privacy Preservation Techniques in Blockchain

Motivation: Blockchain provides a decentralized, tamper-proof and verifiable ledger that can record transactions of digital assets, thereby driving fundamental changes in many innovative scenarios such as smart cities, e-healthcare and e-government. However, blockchains face various scalability, security and potential privacy issues such as transaction connectivity, encryption key management (e.g. retrieval), on-chain data privacy or compliance with privacy regulations. The analysis is performed using the techniques adopted for data protection, publication year, utilized tools, employed dataset, and evaluation metrics. From the analysis, it is proven that asymmetric key generation-based technique is the highly utilized technique for data protection. The blockchain techniques used for privacy preserving and utilizing the block security based on encryption method.Relevance survey: A de tailed survey is elaborated in this paper for the classification of data protection techniques in blockchain. The reviews are gathered from 25 research papers and the techniques are classified into three types, such as identity data anonymization, symmetric key, and asymmetric key generation-based techniques. The papers that are mostly obtained in the year of 2021 was taken into account for this research.Research outcome: The techniques utilized in most of the research papers were evaluated based on the security parameter, and the ninth survey paper utilized five datasets for developing the model. And result outcomes utilized the security, time complexity, encryption decryption time.