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Bitcoin is one of the best-known cryptocurrencies, which captivated researchers with its innovative blockchain structure. Examinations of this public blockchain resulted in many proposals for improvement in terms of anonymity and privacy. Generally used methods for improvement include mixing protocols, ring signatures, zero-knowledge proofs, homomorphic commitments, and off-chain storage systems. To the best of our knowledge, in the literature, there is no study examining Bitcoin in terms of differential privacy, which is a privacy notion coming up with some mechanisms that enable running useful statistical queries without identifying any personal information. In this paper, we provide a theoretical examination of differential privacy in Bitcoin. Our motivation arises from the idea that the Bitcoin public blockchain structure can benefit from differential privacy mechanisms for improved privacy, both making anonymization and privacy breaches by direct queries impossible, and preserving the checkability of the integrity of the blockchain. We first examine the current Bitcoin implementation for four query functions using the differential privacy formulation. Then, we present the feasibility of the utilization of two differential privacy mechanisms in Bitcoin; the noise addition to the transaction amounts and the user graph perturbation. We show that these mechanisms decrease the fraction of the cases violating differential privacy, therefore they can be used for improving anonymity and privacy in Bitcoin. Moreover, we showcase the noise addition to transaction amounts by using IBM Differential Privacy Library. We compare four differential privacy mechanisms for varying privacy parameter values and determine the feasible mechanisms and the parameters.

Applications which are the result of Software Development Life Cycle (SDLC) should be delivered to end users seamlessly. This delivery process which is named as deployment is therefore critical. Especially for systems with ongoing development and frequent deployments, this process should not take a lot of time and create a state of emergency. Also it is important that it is automatized and does not disrupt business continuity. Criticality of transactions increases the importance of deployment process for financial enterprises which are also required to have high performance systems and give uninterrupted service. In this study, deployment of critical financial systems with Service Oriented Architecture (SOA) is addressed and requirements of deployment process are described. Alternative deployment processes for SOA are discussed and compared, "Running from Client via Branch Server" model is proposed with its application architecture and principles of operation. It is shown that this model is the optimum deployment model in terms of performance and availability. The model is detailed in accordance with requirements of financial systems.