A method performed by at least one computer processor, the method comprising: obtaining an original file to be encrypted; encrypting header data of the original file to obtain encrypted header data, the header data comprising metadata of the original file; storing the encrypted header data; recording, to correspond to a file identifier of the original file, a first storage path of the encrypted header data; partitioning file data other than the header data in the original file, into segments; storing the segments in a disordered fragment sequence; and recording, to correspond to the file identifier, second storage paths of the segments along with an actual sequence of the segments in the original file.