Authentication techniques in a monitoring system
US6844816B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1999 |
| Grant date | Jan 18, 2005 |
| Priority date | — |
| Expiry date | Oct 5, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L63/126
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An Electronic House Arrest Monitoring (EHAM) system of the present invention includes a transmitter attached to a monitored offender and a receiver positioned in the vicinity of the desired monitoring location. The transmitter and the receiver each have a pattern stored or generated therein for determining the interval of time between signal transmissions and receptions. The pattern is pseudo-random to offer improved protection against imposter transmitters, in other words the time intervals are selected to be unequal and randomly varying but the pattern is repeated or cycled to allow continuing signal transmission by the transmitter. The transmitter transmits signals at varying time intervals according to this pattern, and the receiver authenticates signals it receives as coming from the monitored transmitter based on the expected time intervals from the pattern. The pattern may include any number of time intervals and, in one embodiment, includes more than one subpattern to extend the length of the repeat cycle to increase the difficulty of defeating the monitoring system. As further protection against imposter devices, the receiver may verify the signals based on information uni…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.