Expressions and concepts related to electronic administration

The following article contains information about the expressions and concepts arising during the electronic administration.



The Citizens Mailbox is available after logging in through the Central Authentication Agent (KAÜ) at


Secure Delivery Service (BKSZ)


The Secure Delivery Service (hereinafter: BKSZ) ensures electronic documents’ delivery under the law’s technical regulations. The BKSZ enables certified document-based communication for organisations and natural persons possessing Citizens or Corporate Mailbox. The BKSZ issues certificates of delivery events with an electronic stamp and an electronic timestamp (Proof of Dispatch, Proof of Download, Proof of Frustration).


Concepts related to electronic administration


Document dispatching

Several methods are available to communicate electronically with Entities providing electronic administration, depending on how the Entity has developed its procedures.

Electronic documents can be sent:


General Form Filling Program (ÁNYK)

This program was developed by the National Tax and Customs Administration and used to fill in and submit forms from the tax authority and other offices. The form filling framework can be downloaded from the NAV website and installed on the User’s computer. The forms to be completed are available on the websites of the Entities providing the administration.


KR type files

KR type files are encrypted files created with the General Form Filling Program (ÁNYK). This file is created in the program after filling in a form and marking it for electronic submission. These files can be submitted directly from the ÁNYK program or the  website, in the “Send” menu.


Reference number


During the document dispatch, each document receives a unique identification number, which can also be found on the Proof of Dispatch issued after the submission. This sequence is used to identify the submitted document.


Permanent storage


Documents received via the Mailbox services are available for 30 days from their dispatch. After that, the documents are automatically deleted and cannot be restored. However, if a document is moved to the permanent storage, that remains available unless deleted by the User.


Attention! After moving an unread (non-notification type) document to the permanent storage, it becomes read by the transfer, and the consignor Entity also receives a notification about the fact of receipt. (The Service issues Proof of Download.)


Proof of Download


The Proof of Download confirms that the recipient has downloaded the dispatched document from its Mailbox. If the consignor Entity sends a notification type document (e.g. NTCA receipts about the application’s acceptance), the system does not generate a Proof of Download.


Proof of Frustration


If the recipient does not download the document received in the Mailbox within 5 working days, the system sends an e-mail notification entitled „Not accepted document notification” on the following working day, indicating that a document in the Mailbox has not been downloaded yet.

If the recipient does not download the document within 5 working days after receiving the „Not accepted document notification”, a Proof of Frustration is being sent, proving that recipient did not download the document that arrived at the Mailbox. This document is sent to both the consignor and the recipient.

Proofs of Frustration are available for 180 days in the „Proof of Frustrations” menu on


Mailbox Administration


The Mailbox Administration is available in the Settings menu of the page. Administrative tasks such as changing the e-mail address of the Mailbox or setting up customer receipt management profiles can be performed here.


For more information about Mailbox services, consult the User’s Guide.