Security Threats and Privacy Challenges in the Quantum Blockchain: A Contemporary Survey

Abstract

Blockchain is an emerging technology that plays a vital role in the field of banking and financial, government, healthcare, and insurance sector. It is used to store the records behind the cryptocurrencies network. This record keeping technology is decentralized, secure digital records, and public ledger of cryptocurrency transac- tions, which is collectively well maintained by various users in the world, rather than by one central administration. Only the parties can create the entries and not possible to alter or delete it. Anyone can check the integrity of the transaction record within the network or outside the network by using simple manipulation. Blockchain technology is continuously evolving to its next stage, which is referred to as quantum blockchain. Quantum blockchain is referred to as a distributed, encoded, and decentralized database system based on quantum computation and quantum information theory. It is more securable because, once the data is stored, then it will not have been maliciously tampered. Even though it has more advantages, it has some security threats and privacy issues. Security issues are attacks to unauthorized resources that are protected by some coding or scripts. Privacy issues mean accessing the private information of a person or organization. It involves the security breaches from their vulnerabilities. Security in quantum blockchain is defined as it gives more protection to transactional information and data in the block from various threats such as internal and peripheral, malevolent, and unintentional threats. Typically, security involves finding of threat, the anticipation of threat, and suitable countermeasures to the threats using security policies, tools, and IT services. Security is one of the major concerns to solve the current computational hardness. Many cryptographic systems and algorithms are more vulnerable against quantum computers. Thus, that is breakable by quantum computers. Hence, with the help of quantum computer and quantum technology, we can make the blockchain more secure. Hence, we are in the position to give privacy and security to all the users and groups for their information and perform transactions without leaking identification information. In addition, it allows a user to remain compliant by discerningly revealing themselves without exposing their actions to the whole network. This chapter mainly discusses the security threats and privacy challenges in quantum blockchain applications.