Memory cards
US4910393A · kind A · utility
21Cited by
2References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1989 |
| Grant date | Mar 20, 1990 |
| Priority date | — |
| Expiry date | Jul 17, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07F7/0866
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A debit card of the type having an integrated circuit on a semiconductor chip embedded in a plastic card includes logic circuitry (10), a counter (2), a ROM (6) and an EEPROM (8) for storing the value of the counter between transactions. By providing two EEPROMs (8A, 8B) in parallel whose values are compared by a comparator (24), the security of the card is increased since operation of the card may be blocked if the two values are not the same, indicating that attempts have been made to fraudulently reprogram the card.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.