All save files are encrypted. Savedatafiler is a dev tool that decrypts them and gives you the core files in a folder called "filer" on the SD card. One of these will contain game data (the others are mainly used for encryption process as I understand) and from there it's just a matter of using a hex editor and experimenting. After that , you can import the files back.
Be warned that some games have checks for modified files and can corrupt your save. Had this happen to me with SSB actually. It told me my save was a different date then what it should be.