As one of the most popular applications in recent years, cloud storage has been gradually integrated into all walks of life. In the field of communication techniques for the unmanned aerial vehicles (UAVs), UAVs use sensors to upload collected data to cloud servers during various exploration activities, but UAVs can only store and calculate valid information currently collected due to the limited storage and computing performance. In the actual exploration, UAVs need not only to upload complete data to the cloud server, but also to support the data dynamic update efficiently. Moreover, due to security requirements, the privacy of data uploaded by UAVs must be protected. However, the existing auditing schemes for dynamic data and integrity have many problems, such as high computation cost, low efficiency of dynamic update, low privacy and security. For this reason, we propose a public cloud audit scheme that supports dynamic data and privacy protection based on distributed string equality check protocol and Merkle-hash tree multi-level index structure. First of all, a third-party server (TPS) is set between the cloud service provider and users, which complete digital signature, integrity auditing, and data dynamic operations significantly in place of users to reduce the local computing cost. Users then locally upload data which has been encrypted to the TPS. Secondly, to further improve the security of the scheme, TPS implement signature for encrypted data based on the distributed string equality check protocol. By designing authorizations with time constraints, it is guaranteed that only the legitimate TPS with time constraints can operate with cloud servers. Finally, we implement dynamic data operation efficiently based on MHT multi-level index structure. The security proof and performance analysis show that our proposed scheme is safe and effective.