The vehicular cloud is a promising new paradigm, where vehicular networking and mobile cloud computing are elaborately integrated to enhance the quality of vehicular information services. Pseudonym is a resource for vehicles to protect their location privacy, which should be efciently utilized to secure vehicular clouds. However, only a few existing architectures of pseudonym systems take exibility and efciency into consideration, thus leading to potential threats to location privacy. In this paper, we exploit software-dened networking technology to signicantly extend the exibility and programmability for pseudonym management in vehicular clouds. We propose a software-dened pseudonym system, where the distributed pseudonym pools are promptly scheduled and elastically managed in a hierarchical manner. In order to decrease the system overhead due to the cost of inter-pool communications, we leverage the two-sided matching theory to formulate and solve the pseudonym resource scheduling. We conducted extensive simulations based on the real map of San Francisco. Numerical results indicate that the proposed software-dened pseudonym system signicantly improves the pseudonym resource utilization, and meanwhile, effectively enhances the vehicles' location privacy by raising their entropy.