Realizing privacy aspects in blockchain networks

The right to personal privacy is known as a fundamental human right allowing people to restrict access to their personal information. The decentralized nature of blockchain networks, often involving the publicity of ledger information, can come into conflict with this right. This is in particular the case when the blockchain maintains sensitive information such as financial credits or medical information. In this paper, we discuss this interaction. We first describe multiple aspects of privacy such as its practical limit towards authorities, its potential vulnerability, and its association with technological systems such as blockchain networks. Towards answering these challenges, we survey a wide range of techniques relying on tools from the areas of cryptography, distributed system, and hardware architecture. We explain how each can be used to enhance privacy in blockchain networks following their unique nature. We further conclude that none of the available techniques can fully answer the complex practical requirements, and that practical solutions should combine both centrally controlled and decentralized systems.

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