Encipher method and decipher method
US5218638A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 5, 1991 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Dec 5, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/601
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for carrying out limited encipherment broadcast by generating a cipher key obtained from destination information added to service information are provided. An information service station transmits to each receiving station a random number, destination information for designating a destination station, and enciphered data obtained by enciphering service information by a common key generating by using the random number and destination information. An IC card at each receiving station which is provided in advance with a key generating function from the information service station, generates the common key by using the received random number and destination information only when it is confirmed from the destination information that the receiving station has a data reception right, and deciphers the enciphered data by using the common key to obtain the original service information. The processing time required for generating the common key can be reduced because of a small amount of data to be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.