System method and apparatus for authenticating an encrypted signal
US5351293A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1993 |
| Grant date | Sep 27, 1994 |
| Priority date | — |
| Expiry date | Feb 1, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/56
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A cryptographic communications system includes a method and apparatus for exchanging messages between a user terminal, containing a secret key, and an operations center wherein each party authenticates signals received from the other party before any other information is exchanged. An initial identification message from the user terminal to the operations center contains an encrypted value of current time. The operations center checks the received message against local time to verify real time concurrent operation of the user terminal. Subsequently, the operations center and the user terminal mutually exchange encrypted challenge blocks, and each provide respective encrypted responses to the encrypted challenge blocks. The challenge and response exchanges demonstrate that each knows the secret key stored in the user terminal before other information, such as downloaded credit or uploaded data usage, is exchanged. In particular, the challenge and response messages exchange a first random number generated in the user terminal and a second random number generated in the operations center, which are variables used in conjunction with the user secret key to generate a new session key fo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.