A Study of Smart Cards

Cards are quite an interesting species of object that have invaded our lives in every way: we either use them for public transit, laundry, gift cards, phone cards, credit cards etc… One could gather quite a lot of power buy not only understanding their functioning, but also by being able to tamper their data. I must admit that I have absolutely no knowledge (or almost) of those devices, but hopefully, by the end of this project, this will have completely changed.

Visual Study of Smart Cards

Smarts card are usually the size of the credit cards and dimensions are defined accordingly to the ISO/IEC 7810 standard. The standard defines four card sizes: ID-1, ID-2, ID-3 and ID-000. Smart cards are usually comprised in the ID-1 category although some are into the ID-000 category, which mostly comprise of SIM cards. Each of them are 0.76 mm thick. The properties are defined as follow¹:

The material use for the card is usually Polyvinyl chloride (PVC). Of course the most interesting item on rhe card is that golden connector. There are various type of connectors as shown in the picture below:

There are also three main types of smart cards: contact cards, contactless and vault cards [2]

Actually the two that are actually important in everybody’s life are the contact and contactless cards, the latest being use in public transit most of the time. For now I’ll concentrate on contact cards.

Contact Cards

Information is transferred using electrical connectors, i.e the golden chip on the card to the reader. Usually, the chip as around 8 connectors as follow:

Now contact cards are divided in two categories : memory cards and multiprocessor cards. Memory cards are furthermore divided into 3 categories:

• Straight Memory Cards
• Protected/Segmented Memory Cards
• Stored Value Memory Cards

The Project

I recently got handed a laundry smart card and for some reason, got fascinated with it. I never really played with hardware but studying those devices have interested me to the point of studying them in a special project. The goal is to be able to modify the contents of the memory of the card. This project will be conducted in two phases :

1. Dump the content of the memory into my computer
2. Alter the content and write it back to the card

System Description

A client is handled a Smart Card called “SmartCity” from a company called Coinamatic, which provide laundry solutions to property managers. The card can be loaded and recharged using coins or debit/credit cards through “reload centers“. You can put up to 50$ maximum on the card. To use the facilites, you need to insert the card  into a slot built into the washers/dryers. The washer is a Commercial Energy Advantage Top Load Washer MAT14PRAWW model. The dryer is a 27″ Commercial Single-Load Electric Stack Dryer model MLE24PRAZW.

Next post : the card reader/writer

See also:

EMV 4.2 Specification, EMVCo, May 2008, http://emvco.com/ accessed on 2009-07-20

Infineon SLE4442, Flylogic Engineering’s Analytical Blog, December 1st, 2007, http://www.flylogic.net/blog/?p=17 accessed on 2009-07-20

How-to: Read a FedEx Kinko’s smart card (SLE4442), Ian Lesnet, Hack-a-day, November 28th, 2008, http://hackaday.com/2008/11/25/how-to-read-a-fedex-kinkos-smart-card-sle4442/, accessed on 2009-07-20

Intelligent 256-Byte EEPROM SLE 4432/SLE 4442, Siemens, 1995, http://www.smartcardsupply.com/PDF/DS_sle4432_42_0795.pdf accessed on 2009-07-20

Kinko’s Smart Card (Siemens SLE4442 memory chip), Strom Calson, http://www.stromcarlson.com/projects/smartcard/format.pdf accessed on 2009-07-20

1K EEPROM – Security Logic with Two Application Zones AT88SC102, Atmel, 1999, http://www.datasheetcatalog.org/datasheet/atmel/DOC1419.PDF accessed on 2009-07-20