Privacypreserving taxcase processing Taxcase processing is based on a classification of common taxable conditions, e.g. retirement benefits, social security benefits, income brackets. Based on those, groups of people fall under certain categorizations and should be treated equally. However, to maintain privacy, people from the same group might be handled anonymously by different case handlers. Consequently, taxcase processing for different individuals from the same group categorization may end up with different results, depending on the region in which the case is dealt with and which case manager treats the given case. This situation maintain privacy but violates fairness. On the other hand, some of the tax calculation is personal since there is no isolation between the taxable conditions data and the individual data. Often, taxable data provides personally identifiable queues. Furthermore, tax processing cannot take advantage of previous taxcase processing that has been already conducted; thus, reducing the systemu0027s overall efficiency for cases that has been already processed. To improve efficiency and transparency of the taxation process, we have investigated and explored architectural designs for privacypreserving taxcase processing prototypes with the use of blockchain technology. In this article, we provide an overview of the available technologies, classify the architecture, and discuss a proofofconcept implementation that can facilitate those goals. Based on the findings, a number of frameworks is considered and a proofofconcept is made to showcase the design intent. We established, that in some cases it is possible to use blockchain technology for taxcase processing to enhance the privacy and improving the transparency at the same time.

Security and Privacy on Blockchain Blockchain offers an innovative approach to storing information, executing transactions, performing functions, and establishing trust in an open environment. Many consider blockchain as a technology breakthrough for cryptography and cybersecurity, with use cases ranging from globally deployed cryptocurrency systems like Bitcoin, to smart contracts, smart grids over the Internet of Things, and so forth. Although blockchain has received growing interests in both academia and industry in the recent years, the security and privacy of blockchains continue to be at the center of the debate when deploying blockchain in different applications. This paper presents a comprehensive overview of the security and privacy of blockchain. To facilitate the discussion, we first introduce the notion of blockchains and its utility in the context of Bitcoin like online transactions. Then we describe the basic security properties that are supported as the essential requirements and building blocks for Bitcoin like cryptocurrency systems, followed by presenting the additional security and privacy properties that are desired in many blockchain applications. Finally, we review the security and privacy techniques for achieving these security properties in blockchainbased systems, including representative consensus algorithms, hash chained storage, mixing protocols, anonymous signatures, noninteractive zeroknowledge proof, and so forth. We conjecture that this survey can help readers to gain an indepth understanding of the security and privacy of blockchain with respect to concept, attributes, techniques and systems.