System with software usage timer and counter for allowing limited use but preventing continued unauthorized use of protected software

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BACKGROUND OF THE INVENTION

Unauthorized use of proprietary computer programs is widespread. Since development costs of most software are substantial, it is necessary for developers of such software to set licensing fees for the use of such software at a sufficient level to recover such costs and to provide a profit to the developers. Such pricing provides an incentive for some users to attempt to obtain programs at lower costs by unauthorized copying or by using on several sites software which has been licensed for only one site.

Various methods have been employed for preventing the use of programs by persons who have obtained them in an unauthorized manner. Such methods include the use of a hardware "key" which must be used with the program, the encryption of programs, and the use of "trap" conditions.

SUMMARY OF THE INVENTION

The present invention relates to a method for preventing continued unauthorized use of protected software, and more particularly relates to such a method in which unauthorized use is initially permitted, and in which the user is warned that the use is unauthorized and is encouraged to obtain a proper registration of the program before the program is disabled. This method has the dual advantages of providing protection for the software and ultimately causing its destruction if a proper license is not obtained, while at the same time encouraging the unauthorized user to register the software and commence licensed use, thus providing revenue to the owner of the software. In this connection, it is noted that once the unauthorized user has commenced use of the program, he is likely to become somewhat dependent upon it, and is therefore more likely to decide to license the program, to the subsequent advantage of the owner of the program.

In accordance with one embodiment of the invention, a method for preventing continued unauthorized use of protected software in a data processing system including a clock, storage means and a counter comprises the steps of providing an initial time setting for said clock at the time of installation of the software in said data processing system; providing a constant representing a predetermined amount of time in said storage means at the time of installation of the software; incrementing the counter each time that the protected software is operated; making a first determination whenever the protected software is operated as to whether the constant has been provided in the data processing system; making a second determination as to whether the counter has reached a predetermined value; making a third determination as to whether the current time sensed from said clock exceeds the time when the software was installed by an amount equal to or greater than said constant; if any of the first, second or third determinations are true, sending a warning message to the software user indicating unauthorized use, setting the constant to a predetermined multiple of the current time setting, and switching the counter to cause it to commence decrementing from the setting at which it stood when switched; decrementing the counter each further time the software is subsequently operated; and causing the software to be disabled when the counter has been decremented to a second predetermined value.

It is accordingly an object of the present invention to provide a method for preventing continued unauthorized use of protected software in a data processing system.

Another object is to provide a method for disabling software after a period of use and a warning message if the user does not contact the proprietor of the software and obtain a defusing number.

Another object is to use a system clock in a data processing system to generate a serial number which is unique to the software system on which it was generated, and which can be used to protect said software against illegal installations.

Another object is to provide a software method to protect software against illegal installations in which a unique serial number is generated for each system using the system clock of the associated data processing system, and in which, when the software is registered with the software proprietors, a defusing number based on said serial number is returned to the user, and is employed to prevent disabling of the software, as would otherwise take place in the case of an illegal installation.

With these and other objects, which will become apparent from the following description, in view, the invention includes certain novel features, a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a data processing system in which the method for software protection of the present invention may be employed.

FIG. 2 is a flow diagram of the registration installation phase of the method for software protection.

FIGS. 3A and 3B, taken together constitute a flow diagram of the registration checking phase of the method for software protection.

FIG. 4 is a flow diagram of the registration defusing phase of the method for software protection.

FIG. 5 is a diagram showing the relationship of programs 1 and 2 and associated files.

FIG. 6 is a diagram showing the relationship of programs 3, 4 and 5 and associated files.

FIG. 7 is a diagram showing the relationship of programs 6 and 7 and an associated file.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown a block diagram of a data processing system 10 in which the method for software protection of the present invention may be employed. The data processing system comprises a processor 12 which includes a system timer or clock 14 and a counter 16, which is included in a memory section 17. The processor also includes storage capability, such as a disk storage unit, indicated generally by reference character 18, in which programs, files and other data may be stored, as well as an arithmetic unit, a control unit, and other units which are conventional and not specifically illustrated. Data, including programs and files, may be loaded into the disk storage 18 of the processor 12 by suitable means, such as a tape cartridge 20 or a flexible diskette 22. Output from the processor 12 may be displayed on a system CRT 24 and may be provided in printed form by a system printer 26.

The software which will now be described functions to prevent continued unauthorized use of protected software and to maintain control of sites where the protected software is installed. The method of protection hereinafter described permits unauthorized copies of the protected software to be installed and to operate for a period of time. However if the user does not register the protected software within a predetermined period of time, the protected software will be destroyed. Before it is destroyed, the protected software will operate for another predetermined period of time, but will give a warning message each time that the protected software is executed, informing the user that the software should be registered.

The method disclosed herein provides further protection to