Privacy Preservation of Users in P2P E-Payment System

Bitcoin ecosystem is supposed to be anonymous and untraceable. Nonetheless, Bitcoin offers weak anonymity in practice. The linkable pseudonymity of Bitcoin system raises privacy concerns for users. There are inputs and outputs of cryptocurrencies that link to Bitcoin public addresses. This is vulnerable to possible linkability and traceability of users’ identity, that can lead to information leakage. Input and output addresses of transactions miss unlinkability in Bitcoin. Several attempts to solve unlinkability and untraceability of users’ transactions found not to satisfy all requirements of a practical anonymity for users to transact business with bitcoins securely and privately. In this paper, the authors focused on preserving identity and transactional behaviour of users in bitcoin cryptocurrency transactions. A secure privacy-preserving scheme is presented. The paper incorporates bilinear pairing, elliptic curve (ECC), ring signature and Zero Knowledge Proof to curb users’ privacy breaches. The authors theoretically analysed, and evaluated proposed scheme, which is proven secure and robust to implement for preserving users’ privacy in bitcoin transactions. The proposal adds a compatible privacy-preserving layer on top of the Bitcoin blockchain, and consistent with the current Bitcoin architecture without offering any modification.