System for controlling access to a function having clock synchronization
US5737421A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 22, 1996 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Mar 22, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/215
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The system includes a first card-like unit adapted to communicate with a second unit. The second unit grants conditional access to a function or service in accordance with an authentication operation. Both units are capable of running software for generating passwords by means of encryption of several dynamic variables as for example a time dependent variable and/or a variable representing the number of formulated authentication requests. The encryption may be performed using a dynamic key. In order to synchronize the values of the variables generated in concert but independently in the units, only some of the least significant digits of the variables are transferred from the card-like unit to the other unit, with the transfer being performed by adding the digits to the password. This synchronization information is combined with corresponding variables in the second unit and used to calculate therein a value which has to match with the password calculated in the second unit in order to gain access to the function or service.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.