Cryptographic protection of usage restrictions in electronic devices
US8225110B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 2009 |
| Grant date | Jul 17, 2012 |
| Priority date | — |
| Expiry date | Dec 22, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W88/02
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An electronic device requires valid control keys to change any usage restriction setting. The device is provided control keys, a secret key, and a signed software object including a batch ID and a hash of the secret key. For each control key, the device generates a cryptographic footprint bound to the device and the secret key. A message authentication code (MAC) of each usage restriction setting is generated, the MAC bound to the device and a control key. To change a usage restriction, the device receives a control key, validates it against the stored footprint, changes the usage restriction settings, and generates a new usage restriction setting MAC. The control key footprints are bound to the secret key, but the device retains only a hash of the secret key.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.