Definition
Memory cards are plastic cards with an embedded memory chip. Optically they look the same as smart cards with a microprocessor chip. Nevertheless the technology behind the contact plates is very much different. Memory chips are pure data carriers, the chip itself (as opposed to microprocessor cards) does not need or contain an own operating system.
Data access
The memory access is done via special protocols. These have to be implemented and interpreted by the card reader. Data contents are being written to absolute memory locations in forms of byte strings. Neither the chip itself nor the transmission protocol can carry out a semantical or syntactical check of the concerned data elements. It remains in the responsibility of the terminal software to ensure that the correct data is get or put to and from the correct memory address.
Security
As well simple memory chips provide - depending on the particular chip type - classical security features. The versatile and universally usable memory chip SLE 4428 by infineon for instances offers three very useful features:
- Write protection - PIN
- "Write Once Bit"
- Unique application identifier AID
Usage fields
From the security point of view, memory chips are not that resistant, to use them in high-security environments. They are simply not designed for such usage. Nevertheless, due to the competitive price and the simple the usability of memory cards is utmost versatile:
- Tourist cards
- Customer loyalty cards
- Configuration cards for machines and devices
- Company cards
- Canteen cards
- Pre-paid payphone cards
A special kind of memory cards are prepaid phone cards, which are used in many countries world-wide. For this purpose specially designed chips are used, which carry a one-way counter. These counters are implemented in a hardware design, which allows counting only in one direction. With every write-impuls they change (mostly decrease) their counter value with one unit. Although such cards have never been rolled out in Austria, Austria Card can produce these memory cards on request.