olemus
infoturbes: dokumendi põhimiku sisse tekitatud turvaelement

näiteid
- kinegrammiaken dokumendis
https://resources.reconnaissance.net/wp-content/uploads/sites/12/2016/07/29143750/ovd-kinegram-window-id-700x384.jpg
- aken rahatähel
https://www.leftovercurrency.com/exchange/qatari-riyals/withdrawn-qatari-riyal-banknotes/100-qatari-riyals-banknote-fourth-issue-with-transparent-window/