PORTABLE MEDIUM DRIVING DEVICE, ITS METHOD, COOPERATIVE DEVICE OF PORTABLE MEDIUM AND NETWORK, AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To eliminate the illegal use of a portable medium at the time of using the portable medium individually or in cooperation with a network. SOLUTION: Data ciphered by a data ciphering key D is recorded in the portable medium 106 and a ciphered data ciphering key ciphered by using a user's open key PU in an open key ciphering system is recorded at a part different from the original storing area of the medium 106. A portable medium reproducing device is provided with a means capable of obtaining the secret key PS of the user to decode a data ciphering key D by a data ciphering key decoding means 111 through the use of this key PS and to restore data within the medium 106 by an in-DVD data restoring means 108 through the use of this key D to display. In addition, by constituting to obtain a ciphered data ciphering key through the network, the using quantity or the using effective time limit of the medium 106 are managed, charging is executed and using is restricted.