Initialization method for keyless entry system
US5767784A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 20, 1995 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Oct 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/84
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system for remotely controlling a desired door locking or other function in a vehicle or other protected environment has a transmitter and receiver for communicating a message including a sequence number, the code of a selected function to be performed and an authenticator. An algorithm in the transmitter and in the receiver has a cryptographic key and a seed code. Each algorithm generates the authenticator as a function of both the seed code and the function code; if the authenticators are equal, the message is valid. Upon each transmission the seed code is updated and the sequence number is incremented. The receiver updates its seed code according to the transmitted sequence number to keep the algorithms in synchronism. To initialize the receiver to recognize the transmitter IDs, the receiver is manually enabled for programming, a counter is set to zero, the ID is transmitted from each transmitter, each ID is stored in sequence, and the counter is incremented for each ID received. During access mode only IDs in locations corresponding to the count value and lower values are used for validation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.