Patent ID: 6857071
Filing Date: 2005-02-15
Classification: G06F,G06Q

Abstract:
1. A digital work distribution system for distributing digital works to a user computer, comprising first and second computers which are connected to each other and to the user computer via a network and each of which has a memory and a central processing unit, wherein said first computer executes a program to perform: setting conditions for plural usages of work data to be distributed; encrypting said work data with a predetermined encryption key; generating different ticket encryption keys and their corresponding ticket decryption keys, each of said ticket encryption keys and its corresponding one of said ticket decryption keys being associated with conditions for one usage among the set conditions for the plural usages; encrypting a predetermined decryption key corresponding to said predetermined encryption key, by using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages; and encapsulating said work data and said predetermined decryption key encrypted using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages, and generating a capsular work which contains said work data and said predetermined decryption key; and said second computer executes a program to perform: storing, in association with each other, the conditions for the plural usages which have been set by said first computer and said ticket decryption keys corresponding to said ticket encryption keys generated each in association with the conditions for one of the plural usages and used to encrypt said predetermined decryption key; encrypting, in reply to an external request for use of said work data received over the network from a user computer, a ticket decryption key which is associated with the conditions for one usage corresponding to the request among the stored ticket decryption keys; distributing the encrypted ticket decryption key to a requester at the user computer who has made the request for use of said work data; a third computer which is connected to the network and which has a memory and a processor, wherein said third computer performs acquiring said capsular work generated by said first computer; acquiring a ticket decryption key corresponding to a ticket encryption key associated with the conditions for a desired one of the plural usages and contained in the acquired capsular work; decrypting, with the acquired ticket decryption key, the encrypted decryption key contained in said capsular work; decrypting said work data contained in said capsular work by using the decrypted decryption key; and reproducing the decrypted work data; and wherein said first computer further performs generating charging modules to effect processing of making a charge for the work data to be distributed, each of said charging modules being associated with the conditions for one of the plural usages; and further encapsulating, in said capsular work, said charging modules generated each in association with the conditions for one of the plural usages; and said second computer further performs storing pieces of charging module identification information for identifying said charging modules, in association with the conditions for the plural usages, and distributing, to the requester who has made the request for use of said work data, a piece of charging module identification information associated with the conditions for one usage corresponding to the request among the stored pieces of charging module identification; and said third computer further performs extracting said charging modules contained in the acquired capsular work and storing the extracted charging modules; and executing the processing of making a charge for said work data by employing one of the stored charging modules in accordance with the piece of charging module identification information transmitted in reply to the request for use of said work data.