Encrypt row fields with a per user salt. Backup this salt separately from the rest of the data in an easier to access media. When deletion of a full row is ne

Encrypt row fields with a per user salt. Backup this salt separately from the rest of the data in an easier to access media. When deletion of a full row is needed, you just need to delete the salt from the comparatively smaller and quicker salt backups, as well as the live row+salt.