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Browse Prior Art Database

Secure Alarm Sensing Method

IP.com Disclosure Number: IPCOM000086542D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Boothroyd, WA: AUTHOR

Abstract

An alarm system or method for securing remote area 1 against forcible entry, where the alarm system communication link 2 and 3 passes through an unprotected region, must itself be protected against tampering. This is done by including, in host 4, random number generator 5, the output of which is encrypted at 6 using key 7 and transmitted on line 2 to remote unit 1. There it is decrypted at 8 using key 7'. The now decrypted random number is combined in the arithmetic logic unit 9, according to logical or arithmetical function 10, with alarm status 11 representing the security status of remote unit 1.

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Secure Alarm Sensing Method

An alarm system or method for securing remote area 1 against forcible entry, where the alarm system communication link 2 and 3 passes through an unprotected region, must itself be protected against tampering. This is done by including, in host 4, random number generator 5, the output of which is encrypted at 6 using key 7 and transmitted on line 2 to remote unit 1. There it is decrypted at 8 using key 7'. The now decrypted random number is combined in the arithmetic logic unit 9, according to logical or arithmetical function 10, with alarm status 11 representing the security status of remote unit 1. The result is transmitted back to host 4 in clear text on line 3 where it is combined with the original random number 12, using the analog 101 of the logical or arithmetical operation 10 performed at the remote unit 1, to yield in clear text at host status register 11' the status character 11 generated at the remote unit 1.

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