Abstract: Aiming at the problem that the protocol designed by Chen et al. has the defect that private information is easy to be cracked, this paper proposes an improved security protocol based on blockchain. We combined the traditional RFID technology with the new blockchain technology and used the advantage of decentralization to create a secure authentication protocol. The improved protocol used the super lightweight self-designed algorithm for information encryption, that was, traversing the reverse XOR operation. According to the different Hamming values of the two parameters, the operation could traverse the sequence in different ways, which increased the difficulty of cracking, and would not introduce more parameters, which could effectively reduce the storage capacity. Through comprehensive comparison and analysis of various protocols, the protocol in this paper can resist common type of replay, exhaustive and other attacks, and is superior to other protocols in terms of computation. It can be used in computing restricted tags.