The Internet of Things (IoT) has built up to create a network ecosystem with millions or billions of devices connecting real-life fields and opening new business opportunities. Yet, securing these devices from an authentication standpoint is far easier said than done. Even though Kerberos is a very dominant protocol, still it suffers from lack of scalability due to centralised single-point failure and some security threats like intruder attacks. In this paper, we present an upgraded Kerberos authentication system which uses blockchain technology to overcome these challenges. Towards this end, the proposed approach is beneficial and suitable for secure tourist data sharing using a decentralized authentication technique to shift from symmetric-to-asymmetric cryptography which helps in providing high-security levels with fault-tolerant mechanism. The paper also contains a complete mathematical proof of the scheme algorithm correctness and compares with other authentication methods in IoT environments, proving that it proposes advantages on mentioned approaches.