<p>To address the security risks arising from the lack of identity authentication in existing quantum secure summation protocols, a cluster-state-based summation protocol integrated with bidirectional identity authentication mechanism is proposed. The proposed scheme employs four-particle cluster states and their equivalent rewritten forms as quantum information carriers and constructs a bidirectional authentication framework based on pre-shared secret identity information and hash functions. With the assistance of a trusted third party (TP), the scheme enables bitwise XOR summation of private bit strings held by four participants. Relying on fundamental principles of quantum mechanics, including the uncertainty principle and the no-cloning theorem, the proposed scheme achieves information-theoretic security without assuming the computational hardness of hash functions and effectively resists external eavesdropping, identity forgery, and malicious participant attacks. Furthermore, the scheme provides one practical and efficient quantum-resistant solution for secure cloud computing and privacy-preserving data aggregation applications.</p>