Patent ID: 7487351

Claim:
A data use management system comprising at least one receiving apparatus connected to a network and capable of receiving and using predetermined data, and a transmitting apparatus which transmits the data to said receiving apparatus via said network, wherein use of the data on said network is managed on the basis of a transmitting time for transmission of predetermined information between said transmitting apparatus and said receiving apparatus, wherein said transmitting apparatus has: transmission time measuring means of measuring the transmission time for transmission of the predetermined information for measurement between said transmitting apparatus and said receiving apparatus; reference time storage means of storing a plurality of reference times; transmitting-side authentication means of comparing the transmission time and the plurality of reference times, thereby determining to which one of ranges of transmission time classified on the basis of the reference times the transmission time belongs, determining, on the basis of the result of said determination, whether or not said receiving apparatus having the transmission time is permitted to use the predetermined data, and performing authentication if said receiving apparatus is permitted to use the predetermined data; and authentication count means of incrementing an authentication count which is a number of instances of authentication performed by said transmitting-side authentication means, wherein said receiving apparatus has receiving-side authentication means of performing authentication with said transmitting-side authentication means, and wherein said transmitting apparatus compares the authentication count with a maximum authentication count determined in advance with respect to each of the ranges of transmission time, and inhibits further authentication if the authentication count is larger than the maximum authentication count; wherein said transmitting-side authentication means sets the maximum authentication count to a smaller value based on a result of said classification of the plurality of ranges so that a class with greater transmission time is set to the smaller value of the maximum authentication count.