Security evaluation of certain blockchain-based systems – An illustrative example

Abstract

Over the years, blockchain surpassed the initial application solely related to cryptocurrencies and finance, and it is seen today as a general - purpose technology that can be used in many other use - cases. The key enabler for blockchain widespread usage is the concept of smart contracts, which brought the programmability potential into blockchains. One of the fruitful research directions on blockchain applications is in the subject area of authentication, authorization and access control, where the blockchain technology is used, on the one hand, to fortify the security and, on the other hand, to overcome the need for a central authority. However, when designing blockchain-based systems, we have to carefully take into consideration inherent characteristics and limitations of blockchains. On the example of a recently published authentication protocol for wireless medical sensor networks, we will show how inappropriate employment of the blockchain technology can undermine the system and can cause multiple vulnerabilities of the protocol.