Password protected device using incorrect passwords as seed values for pseudo-random number generator for outputting random data to thwart unauthorized accesses
Patent 5206905 Issued on April 27, 1993. Estimated Expiration Date: 
November 19, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 19, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesComputer key and computer lock system Random number generator using sampled output of variable frequency oscillator Integrated circuit random number generator using sampled output of variable frequency oscillator Communications network using IC cards Electronic key locking circuitry Time-key integrated circuit Patent #: 5010331 InventorsApplicationNo. 615606 filed on 11/19/1990US Classes:705/55, Requiring a supplemental attachment or input (e.g., dongle) to open340/5.26, Code rotating or scrambling340/5.54, Password340/5.65, Electronic coded record380/46Nonlinear (e.g., pseudorandom)ExaminersPrimary: Anderson, Lawrence E.Assistant: Ellis, Richard L. Attorney, Agent or FirmInternational ClassG06F 012/14AbstractAn electronic key which includes a pseudo-random number generator. If the correct password is received, the contents of a secure memory will be outputted by the electronic key. However, if an incorrect password is received, that password will be used as a seed value for the pseudo-random number generator, and the resulting value will be outputted.Thus, if a copier exercises the key through all possible passwords, the incorrect passwords, as well as the correct password, will result in the same output data every time it is tried. | |
