Patent ID: 6449721
Filing Date: 2002-09-10
Classification: H04L

Abstract:
A method of controlling distribution of a segment of encrypted electronic information, comprising:receiving, at a user location, a user code and an identification of the segment; transmitting the user code and the identification from the user location to a key server; receiving, at a user location from a key server in response to the user code representing a user authorized to view the segment, a decryption key for the segment and at least one access policy associated with the segment; decrypting the segment with the decryption key into clear text in response to said receiving; destroying the decryption key in response to said decrypting; rendering the clear text; limiting access to the clear text consistent with the at least one access policy; and defending the decryption key at the user location when the decryption key is resident at the user location; wherein a processing between and including said receiving the decryption key and said destroying the decryption key occurs with sufficient speed such that the decryption key is only resident at the user location for a moment, and said defending resists capturing of the decryption key during the moment.