Even if the cloud computing provides a wide variety of resources to its clients, the security issues like Denial of Service (DoS) attacks, loss of important data and sensitive data compromising lead to crucial problems. From the recent survey on protection of sensitive data, there is paucity of security in DoS attacks. In this paper, we have studied the Quantum algorithm approach and focused on the Quantum Swarm Evolutionary (QSE) algorithm and the Quantum-inspired Evolutionary Algorithm (QEA). The main aim of our work is to apply QSE algorithm with comparison of QEA on cloud computing to detect DoS attacks. We conducted an experiment methodology that shows that QSE is step above than the traditional QEA in this context.