Security using blockchain-based OTP with the concept of IoT publish/subscribe.

Modern applications are continually attracting interest in the Internet of Things, transforming our daily lives and empowering industrial applications. Because contrary to economic and energy consumption requirements, interaction and collaboration among intelligent devices pose new security issues. The lack of security measures, on the other hand, may have a detrimental impact on the implementation of this paradigm. The MQTT protocol, which is widely used on the Internet of Things, is the subject of this study. Developers want secure authentication procedures, which this protocol does not provide. As a result, this article offers a novel OTP (one-time-password) authentication schema for MQTT, which implements a second factor out-of-band channel using the Ethereum blockchain. The idea uses Ethereum smart contracts to enable authentication of both local and remote devices while maintaining user privacy and ensuring trust and accountability. [ABSTRACT FROM AUTHOR]