Method and apparatus for transmitting and receiving encrypted signals
US5920625A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 18, 1997 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Feb 18, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/1696
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An encrypted signal compatible with first and second encryption systems is generated by producing encryption data signals relating to each encryption system. A difference signal is derived from the two encryption data signals and the signal to be encrypted is encrypted in accordance with one of the encryption systems. At an output the encrypted signal, the two encryption signals, and the difference signal are made available. At a decoder compatible with, for example, the first encryption system, the encrypted data, the second encryption data signal, and the different signal are received. The decoder can then derive the first encryption data signal from the second encryption data signal and the difference signal and can then decode the encrypted signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.