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Document Summary

This note describes a method of data signature management which allows keeping track of the Calypso SAMs generating these signatures. It presents algorithms and examples for terminals needing to generate or to verify such signatures.

In a system based on the usage of contactless cards, it may be necessary to ensure the identity of the entity which issued the card data (e.g. bus tickets) and wrote them in the card, and which may have received some

payment in return.

This note relates to different kinds of data that may need issuer authentication:

  • Information about the card issuing, stored as a data structure called environment.

  • The rights entitled to the card holder are stored as data structures called contracts. Independent data structures called counters, dedicated to counting arbitrary units, may be linked to each


  • The transaction history is stored as data structures called events.

Additional Information

Document Published:

23 Mar 2022

Document Type:

Technical Note





Calypso Solution:

Card, Mobile, Terminal, Central System, SAM

Calypso Product:

Prime, Light, Basic, Applet, HCE, SAM-C1

Benefits & Services:


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