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, 1984
Filed:
Nov. 19, 1981
Lin-nan Lee, Germantown, MD (US);
Russell J Fang, Brookeville, MD (US);
Communications Satellite Corporation, Washington, DC (US);
Abstract
In a secure communications system, a key number which is changed periodically, e.g. monthly, and a random number from a random number generator are combined and used as a seed to reset a PN sequence generator, with the output of the generator being used to control encryption of transmission data in a signal processor. The key is also provided to a first encipherer to encipher the random number for transmission with the encrypted data. At the receiver, the key is provided on common to a decipherer for deciphering the random number and a PN sequence generator which is periodically reset by the combination of the key and random number in the same manner as in the transmitter. The PN sequence is then used to decrypt the information. User identification codes are stored in the transmitter and are used to encipher the key, with each employing its ID code to decipher the key. The user ID codes are known only to the system operator, so that not even a particular user can know the key.