The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 20, 1990
Filed:
May. 01, 1989
Michael J Sabin, Sunnyvale, CA (US);
Cylink Corporation, Sunnyvale, CA (US);
Abstract
A integer encryptor and decryptor, with the integer encryptor comprising a pseudorandom source, a discrete-time source, guard-band means, and adding means. The pseudorandom source generates a random-data signal. The random-data signal is an integer that lies within a first-bounded range. The discrete-time source generates the input-data signal. The guard-band means is coupled to the discrete-time source. In response to the input-data signal, the guard-band means generates an output-data signal. For a second-limit number the guard-band means limits the output-data signal to lie within a second-bounded range. The second-limit number is less than the first-limit number. The modulo-adding means is coupled to the pseudorandom source and the guard-band means. The modulo-adding means repetitively adds the output-data signal with the random-data signal and a third-limit number and generates an encrypted-data signal. The present invention also includes an integer decryptor having a pseudorandom source and modulo-adding means. The pseudorandom source generates a negative-random-data signal. The negative-random-data signal is the negative of the random-data signal generated at the integer encryptor. A communications channel outputs a channel signal, with the channel signal being a sum of the encrypted-data signal and an error signal. Modulo-adding means is coupled to the communications channel. The modulo-adding means repetitively adds the negative-random-data signal, the channel signal, and a fourth-limit number, and generates a receiver-output-data signal.