MQTT protocol data security with OTP blockchain-based identity and data verification

The widespread Internet of Thing presence in almost every aspect of our lives has been made possible by the fast development of technology these past few years. The internet of things is in a wide area. For example cell phones, tablets, computers and all other devices with sensors. Among the technologies used to facilitate efficient communication, between these IoT devices the MQTT protocol stands out. Exposure of security vulnerabilities existing in MQTT, and the development of effective countermeasures is a key objective of this thesis. The MQTT server's client architecture was built between the Raspberry Pi and the computer. To be used by MQTT Broker and publisher subscribers, Python programs have been developed. The use of the wireshark API has been recommended to check for system security vulnerabilities. During that process, the safety issues at packet and module level have been examined in an experimental manner. The MQTT protocol has been found to be vulnerable to attacks. Although encryption can be performed on port 8388 with Secure Sockets (SSL) and Transport Layer Security (TLS) protocols to address the security vulnerabilities found in the standard MQTT configuration, this is not preferred and is not scalable. Instead, a structure has been developed on port 1883 again, using smart contracts, digital signatures to only allow authorized users to connect to the MQTT broker, providing authentication and encryption for the publisher and subscriber. Extra security measures are offered with authentication, message denial, data integrity, and selective privacy. In the area of Smart Contracts major progress has been made. A smart contract, ensuring transparency and traceability in every transaction offering benefits, plays an important role. Smart contracts consist of an automated set of instructions which, when certain conditions have been fulfilled, shall be executed automaticly. Users' permissions as well as Digital Signatures could be included in these conditions. Better scalability is also provided by this system. Using A system has been developed using Smart Contract technology to perform user authentication and permission management for users connected to an MQTT broker. Authorization processes such as adding, removing, granting, or denying user permissions can be executed through a smart contract. Similarly, a user seeking to access and publish or read data on the MQTT broker must not only possess the necessary authorization but also approve a digitally signed message based on their unique OTP (One-Time Password) information. The Elliptic Curve digital signature algorithm is used for this signature. Users with access permissions can verify the digital signature using their public key and OTP information. Once the smart contract confirms the user's permission to publish data, they can proceed with their publication or perform encrypted data readings This design is intended to stop entry and manipulation of data, within the system. In contrast with the data security offered by SSL or TLS, this new and effective method provides additional protection against attacks on data centre such as potential Distributed Denial of Service attack from Sybil. Upon completion of this thesis, it was determined that the Broker gained immunity against attacks due to the implemented security measures.Consequently the thesis offers an examination of MQTT in relation, to attacks and suggests an enhanced security mechanism to counteract these attacks.