Patent ID: 6128605
Filing Date: 2000-10-03
Classification: G06F,G06Q,G06T,G07F,H04L,H04N

Abstract:
A data copyright management apparatus used in a user terminal for decrypting encrypted input data using a first secret-key to produce decrypted data for display or edit operations and for re-encrypted data said decrypted data using a second secret-key to produce re-encrypted data for store, copy, or transfer operations,said user terminal comprising a microprocessor, a system bus connected to said microprocessor, a read-only semiconductor memory and a read/write memory connected to said system bus;said data copyright management apparatus comprising a central processing unit, a local bus connected to said central processing unit and to said system bus, a read-only semiconductor memory and a read/write memory connected to said local bus;either one of said microprocessor of said user terminal and said central processing unit of said data copyright management apparatus being programmed to perform decryption of a first amount of said encrypted input data by using said first secret-key to produce said decrypted data;said user terminal further comprising means for displaying or editing said decrypted data;the other of said microprocessor and said central processing unit being programmed to perform re-encryption of a previously decrypted second amount of said encrypted input date, different from said first amount of said encrypted input data, by using said second secret-key, at the same time as the decryption of said first amount of said encrypted input data, to produce said re-encrypted data; andsaid user terminal further comprising means for storing, copying, or transferring only said re-encrypted data.