Digital Security Elements for Rail Passenger Ticketing

In the past, railway ticketing was protected by means of SiP (Security in Paper) mechanisms. Security was ensured by using a specific type of paper, making it impossible for anyone other than the ticket issuer to print or modify tickets.

In international ticketing, the security background - together with legal and functional specifications and frameworks for verification, cancellations and after-sales services - is defined by CIT and ticket layout is defined by UIC to ensure that tickets can be recognised by all railway companies involved.

Security in Paper has some limitations: tickets must be printed on special printers with a stock of secured paper applying ticket stock management control, making it difficult to sell tickets over the Internet (fulfilment issues). On the other hand, Security in Paper has the advantage of ensuring that the contract is unique and cannot be duplicated. Any status changes to the ticket can be printed on the ticket itself, applying the amendments to the original contract.

Modern ticketing systems using SiD (Security in Data) are defined not only by layout (recognisable to all TCOs involved), but also by the security elements used. These security elements allow TCOs to verify that the content has not been created or modified by anyone other than RUs. Reading/verification must be facilitated without granting the party checking the ticket the right to create the security elements. A so-called asymmetrical security algorithm is used for this purpose.

The mechanism of generating AZTEC-barcodes for international ticketing is described in detail for different barcodes that can be used in different situations: