Hi, if you try to do this on an android device do the following:
1. Connect your device to a computer.
2. Enable PTP
3. Create, on your computer, a file called security_keys.txt with the text: Signing-key (and nothing else).
4. Make that file read only.
5. Transfer that file to your device.
6. Replace the signing_keys.txt file inside the folder that holds your saves with the file you had created.
*7. Open the game, load the fixed file and then save to a new spot.
*8. Close the game and delete the altered security_keys.txt.
*9. Reopen the game (so it will recreate the original security_keys.txt) and open the NEW save, it will ask you one time if you sure but will let you to open.
*10. Save the game again and there should be no problems henceforth.
11. Enjoy.
* 7-10 are to address the concern about not having the original security_keys.txt
