05737413 is referenced by 95 patents and cites 9 patents.

A system for use when distributing information stored in a piece of storage medium from a supplier to users through a distributor(s). The information is ciphered when stored in each piece of storage medium in a supplier apparatus. In addition, ciphered key information may be stored in the piece of storage medium together with the above information to be distributed. A distributor apparatus may convert the cipher of the key information before distributing the piece of storage medium to the users. The distributor apparatus may write further information in the piece of storage medium before distributing the piece of storage medium to the users. The further information indicates a limit of an operation of reading the information by each user, and may be a maximum allowable accumulated time of reading the information by each user, a maximum number of repetitions of the reading operation of the information by each user, or a time limit of the operation of the reading operation by each user. Each user apparatus stops the reading operation when the reading operation has reached the limit. Further, each user apparatus may write information indicating an amount of the reading operation therein, in the piece of storage medium, and the distributor apparatus may compare a sum of amounts of the above limits for pieces of storage medium distributed therefrom, with a sum of the amounts of the reading operations in the respective pieces of storage medium after the pieces of storage medium are returned to the distributor apparatus.

Title
Information distribution system wherein storage medium storing ciphered information is distributed
Application Number
51749
Publication Number
5737413
Application Date
April 3, 1995
Publication Date
April 7, 1998
Inventor
Makoto Yoshioka
Kawasaki
JP
Takayuki Hasebe
Kawasaki
JP
Ryota Akiyama
Kawasaki
JP
Agent
Staas & Halsey
Assignee
Fujitsu
JP
IPC
G06F 3/06
H04L 9/32
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