BLOCKCHAIN TECHNOLOGY SECURITY CONCERNS:LITERATURE REVIEW

Abstract: Blockchain is a technology that allows the decentralization of data stored in a way that there is no single central actor to control or modify the data. Bitcoin is the first successful blockchain application implemented with the concept known as cryptocurrency that allows a transaction flow without any bank or government to control it. Blockchain is associated with benefits including high level of transparency, integrity, trust and confidence for the participants. Blockchain is still at early stage but it is a promising technology that has the potential to impact many more areas in the future. However, its security area is still the weakest part of it which still needs improvement. Therefore, this thesis aims to make a review of the blockchain security issues using the past published literature between 2010 and 2021. This thesis conducts a review on 20 articles to provide a scientific input that gives an overall view of existing security threats and their respective impacts on blockchain system. This thesis starts with an overview of how blockchain system works and briefly discuss on the information security of blockchain. The collection of security attacks from the literature has been carried out by using concept centric matrix approach. This process resulted to security attacks that were classified based on four layers of blockchain system architecture. Then, the security attacks are mapped to common security impacts including double spending, unauthorized code execution, denial of service, unfair income and privacy key leakage. These security impacts were analyzed which led to the conclusion that the major security issues on blockchain result from its P2P network architecture and its consensus mechanism. Besides, some possible solutions to mitigate the security threats were discussed though, more effort in developing new security measures and protocol framework is still required.