The Association of ZVT Host Interface Users (ZVT-H) has published the “Functional Description Payment Terminal ZVT Host”, version 4.4 (ZVT 4.4) from December 18, 2023, as well as the associated specification “ZVT Host Interface – Cryptographic Scheme AES ", version 1.2.1 published on January 10, 2024 and distributed to licensees.

The previously released so-called ZVT bits 4.3 A, 4.3 B and 4.3 C have been incorporated into the new version of ZVT 4.4. These included, among other things, additions to the topics of Strong Customer Authentication, Cashback – Purchase Only Approval, DCC contactless, extended error reporting when loading EMV parameters, Credential-on-File in e-commerce and charging terminals for e-cars.

In addition to various corrections, clarifications and revisions, ZVT 4.4 also includes extensions to online age verification and the key block for online key exchange. In addition, descriptions for track 3 processing and connection via X.25 that are no longer required have been removed.

The expansion to the key block also affects the associated document on AES cryptography. A key block procedure for the 2-key triple DES procedure has now been defined here, including an XML schema for this.

The document also contains revised and corrected example data of various test keys with master keys, derived terminal and session keys, fingerprints, etc.

Interested payment providers or terminal manufacturers who are not yet licensees and are interested in a license to use the ZVT-Host interface can contact the association's board using the contact form located in the status line "general inquiry about the association".

Jörg Stahl