1. A computer-implemented method for backing up electronically stored data files from a client device to a backup archive communicatively coupled to the client device, the method executed on at least one computer processor circuit in communication with a memory, the at least one computer processor circuit configured to obtain instructions from the memory that cause the at least one computer processor circuit to execute the method, the method comprising: receiving a first request to back up a first set of data files from a client device to a backup archive; copying, in response to the first request, with a client backup engine, to the backup archive, and recording, with a transform engine, a file transformation status of an original instance of an at least one data file from the first set of data files; creating and recording the file transformation status of, with the transform engine in conjunction with a set of transforms and a transform map table, in the backup archive, an at least one transformed data file that includes a transformed instance of the at least one data file, by applying an at least one transform, selected from the set of transforms in accordance with the transform map table, to the original instance of the at least one data file; receiving a second request to back up, from the client device to the backup archive, a second set of data files; identifying, with a data file comparison program, in response to the second request, the at least one transformed data file with an instance in the backup archive that has a different file transformation status than an instance of the at least one transformed data file in the client device; and sending, with the transform engine, in response to the identifying, the at least one transformed data file from the backup archive to the client device.