Filter networks are incorporated within a software protection hardware device which is plugged into a communications port of a computer which device will select bits or combinations of bits emanating from the communications port resulting from commands of a controlling software in use with the computer...http://www.google.fr/patents/US4932054?utm_source=gb-gplus-shareBrevet US4932054 - Method and apparatus for protecting computer software utilizing coded filter network in conjunction with an active coded hardware device
Method and apparatus for protecting computer software utilizing coded filter ...
