Data processing: financial – business practice – management – or co – Business processing using cryptography – Usage protection of distributed data files
Reexamination Certificate
1998-12-15
2002-01-29
Stamber, Eric W. (Department: 2162)
Data processing: financial, business practice, management, or co
Business processing using cryptography
Usage protection of distributed data files
C705S051000
Reexamination Certificate
active
06343280
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The instant invention relates to the field of methods of protecting software from unlicensed use. More particularly, the instant invention relates to methods of protecting software from unlicensed use which utilize authentication of digital keys and distributed execution of executable software.
2. Prior Art
It is known in the prior art of protecting software from copying to utilize a system for providing secure access and execution of application software stored on a first computer by a second computer using a communication device while a communication link is maintained between the first and second computers. More specifically, it is known in the prior art to utilize a secure software rental system. The secure server rental system enables a user in a remote location using a personal computer and a modem to connect to a central rental facility, transfer application software from the central rental facility to the remote computer, and execute the application software on the remote computer while electronically connected to the central rental facility. When the communication link between the central rental facility and the remote computer is interrupted or terminated, the application software no longer executes on the remote computer. This interruption or termination is accomplished by integrating header software with the application software. The application software stored on the central rental facility is integrated with the header software to provide the security feature. The use of header software allows the user to execute the application software only while the user is electronically connected to the central rental facility continuously. This use of the header software is intended to prevent the user from copying the application software to a storage device on the remote computer, and subsequently executing the application software after interrupting or terminating the communications link between the central rental facility and the remote computer.
The methodology of utilizing a system for providing secure access and execution of application software stored on a first computer by a second computer using a communication device while a communication link is maintained between the first and second computers fails as a protection against copying because the system downloads the complete executable to the user's machine (with the inclusion of “header software”) making it susceptible to simple cracking techniques which can avoid the protection system by removing the header software. Other forms of header software, such as those that require serial numbers before running the application software, have been shown to be ineffective in protecting software from copying and automated methods of removing the header software have been developed.
It is further known in the prior art of protecting software from copying to repetitively transmit portions or sequences of a retailed (distributed or delivered to an end user) computer program through one way media to a computing device, such that the computing device sequentially executes the transmitted portions or sequences of the retailed computer program, such that a user of the computing device has full use of the retailed computer program, and such that the computing device at no single time has a true, accurate and complete copy of the retailed computer program within the computing device, thereby preventing unauthorized duplication of the retailed computer program by eliminating the presence within the computing device, at any single time, of a true, accurate and complete copy of the retailed computer program.
The method of repetitively transmitting portions or sequences of a retailed computer program through one way media to a computing device, such that the computing device sequentially executes the transmitted portions or sequences of the retailed computer program, such that a user of the computing device has full use of the retailed computer program, and such that the computing device at no single time has a true, accurate and complete copy of the retailed computer program within the computing device fails as a protection against copying because the method allows a complete copy to be assembled from the transmitted pieces of the retailed computer program. No method that operates on a one way medium can be fully secured against unlicensed copying, because simply recording and replaying the transmitted data results in a working copy of the retailed computer program.
It is further known in the art of protecting software from copying to create an encoding technique to protect software programs and hardware designs from being copied, tampered with, and their functions from being exposed. The software programs and hardware designs (collectively called programs) thus encoded still remain executable. The encoding technique employs the concept of complexity of programs and produces proximity inversion in terms of functions contained in the programs, while preserving the behaviors. Various embodiments are possible to achieve this encoding which includes, for example, cascading and intertwining of blocks of the programs. This method of encoding software, while making tampering with the software much more difficult, does not prevent the software from being copied. This technique of encoding software might be combined with other methods of copy protection to make tampering more difficult. But, because this method allows the user complete access to the software, the software can be disassembled, studied, and modified. Given a determined user, software protected from tampering by this method can be reverse engineered because all of the software, in unencrypted form, resides physically on the user's machine.
Other and further copy protection methods are known in the art. For example, it is known to mark a sector on the disk containing the software to be protected as “bad” and store valid data in it. At one time most disk copy software would not copy bad tracks or sectors from a disk. However, such disk copy software is now common.
It is further known in the art of protecting software from copying to copy protect a software being delivered to the customer on a disk (or other physical storage media) by physically manufacturing a defective sector on the disk (or other physical storage media) containing the software to be protected and then to check for this defective sector when the software is loaded into the customer's volatile memory for operation. This software protection mechanism is readily defeated by reverse engineering the software to no longer check for bad sectors (method of modifying is discussed later). Furthermore, this technique of software copy protection requires special manufacturing capabilities, depends on the error detection capability of the software user's drive which may not be consistent across all users, and has the additional drawback that it doesn't allow the software purchaser, the authorized user, to backup his software.
It is further known in the art of protecting software from copying to utilize password based systems to protect software from copying. Typically, in such a system, the user is asked to enter a phrase from the user manual or from a sticker placed on the product's packaging when the software starts. The user manual, itself, was sometimes protected from copying by use of photocopy resistant paper. This method of copy protection for software is easily defeated by manually typing the required information and making it publicly available, or by reverse engineering the software to bypass the password check.
It is further known in the art of protecting software from copying to attach a hardware device (sometimes referred to as a “dongle” or “smart card”) to a communication port as a protection against software copying. The software checks for the dongle sporadically during the software's execution and shuts down if the dongle is missing. This software copy protection mechanism is defeated by finding the code sequence within
Champagne Donald L.
Lee Larry Mason
Stamber Eric W.
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