1. Field of the Invention
The present invention relates to a licensee notification system employed for the sale of software using a high speed communication network such as B-ISDN and a large-capacity storage medium such as a CD-ROM.
2. Description of the Related Art
With the development of high speed communication technology such as B-ISDN (broad-band integrated services digital network) and high-capacity storage media such as CD-ROMs (compact disk read only memory) such means can now be used to distribute computer programs or video data or audio data. For example, video works which were previously supplied on video tape are now being sold stored on CD-ROM. Also, game programs etc, which contain a large amount of picture data, are being sold stored on CD-ROM. The same applies to high speed communication networks, in which the software supplier can now distribute the software by various methods. One of these methods of software sales is the so-called "locked software" sales system. In the locked software sales system, a CD ROM on which are stored a large number of software items whose functions are restricted is sold cheaply. By using the various items of software on the CD-ROM that is purchased, in a condition with the functional restrictions imposed, the end user is able to make a decision as to whether or not he needs each software item. Then, if the end user does require the software, he obtains (purchases) a restriction-removal code corresponding to this software from a management center operated by the software distributor, and is able to use this restriction-removal code to remove the functional restrictions on the software.
Such a sales system may be implemented, as a specific example, using the software sales system shown in FIG. 10. As shown in this Figure, this software sales system comprises user terminals 31 and management center 32. The user terminal 31 and the management center 32 are connected by means of a communication circuit.
When actually purchasing the software (i.e. when purchasing a restriction-removal code), the end user, using a user ID etc, sets up a communication path with the management center and executes the prescribed procedure required to request that a restriction-removal code be sent to the user terminal 31. This procedure includes the input of a "contents ID", which is information for identifying the software item that is to be purchased actually. In response to the execution of such a procedure, the user terminal 31 sends to the management center 32 the contents ID and for example the characteristic information of the user, consisting of the ID of the CPU provided in user terminal 31.
Within the management center 32, there is provided a software database (software DB) in which software decoding keys employed for encoding the various software items are stored in association with the contents ID. When a contents ID is received from user terminal 31, the software decoding key corresponding to the contents ID is read from software database 33. Also, encoding unit 34 in management center 32 generates a user individual key by encoding the user characteristic information from user terminal 31 by the key "Ks". Encoding unit 35 sends the results of the encoding of the software decoding key from software database 33 to user terminal 31 as restriction-removal code, using the user individual key from encoding unit 34.
Encoding unit 36 in user terminal 31 generates a user individual key by encoding the user characteristic information with the key "Ks". Decoding unit 37 uses the user individual key generated by encoding unit 36 to decode the restriction removal code from management center 32, thereby generating the software decoding key. Installation unit 38 then uses this software decoding key to decode the software in CD-ROM corresponding to the contents ID sent to center terminal 32: thus the software is put in a condition where it can be used with the functional restrictions removed, and, in this form, is installed on to a storage device such as a hard disk device.
With such a software sales system, it is possible to determine the software item to be purchased after actually ascertaining its contents: thus, the possibility that the purchased software might be completely different from that intended, as could happen if the purchase were made solely on the basis of the details contained in a catalogue, can be completely eliminated. Also, since the software on the CD ROM is stored in a form which is not executable without knowing special information, illicit installation can be prevented.
However, once the software has been installed, it is an extremely easy operation to copy this. Thus, the problem has arisen of unscrupulous persons copying the software without the consent of the software supplier. Various methods (so-called protection methods) of preventing such illicit copying are known but there is no way to prevent illicit copying by a person possessing knowledge at the level of the BIOS (basic input/output system). Whichever method is used, it can do no more than make it more difficult to perform illicit copying.
For this reason, software is sold in which the name of the authorized user is displayed on start-up, with the object of preventing illicit copying psychologically rather than physically. That is, the aim is to prevent illicit copying of software by displaying the name of the authorized user of the software when the illicitly copied software is executed.
However, even with such software, if the copying is inclusive of the installation software that sets the user name, when the software is run, it can be made to display the name of the person who made the illicit copy: thus, sufficient effectiveness in preventing illicit copying was not obtained.