If a S/MIME encrypted tarball is extracted, a number suffix is added, e.g.

• Archive: single_folder.dnd.smime.tar.gz.p7m
• Folders
  • 1st extraction: single_folder.dnd.smime_1_
  • 2nd extraction: single_folder.dnd.smime_1__1
  • 3rd extraction: single_folder.dnd.smime_1__2

For comparison with pgp archives:

• Archive: single_folder.dnd.pgp.tar.gpg
• Folders
  • 1st extraction: single_folder.dnd.pgp
  • 2nd extraction: single_folder.dnd.pgp_1
  • 3rd extraction: single_folder.dnd.pgp_2

If there's no technical reason for it, the _1_ suffix should be removed.