Method, client device and system for storing services by aid of public cloud

The invention discloses a method, a client device and a system for storing services by the aid of public cloud. The method includes identifying strategy configuration files of a client to determine whether the strategy configuration files contain safety strategies for target files or not; responding to the safety strategies for the target files, and encrypting and/or scrambling the target files according to the safety strategies; uploading the encrypted and/or scrambled target files to a cloud storage server. The target files are files to be uploaded to the cloud storage server. The safety strategies contain operation for encrypting and/or scrambling the target files. The strategy configuration files of the client contain the safety strategies. According to the technical scheme, the method, the client device and the system have the advantage that perfect safety protection can be provided for user data stored in the public cloud storage server.