The Methods of Copy Protection: Binding Objects
The main idea of copy protection is simple. You need to find an object that has two properties: the first, each end user should have it, and the second, it should be difficult to duplicate it. Usually such an object is called a binding object, because it is used to bind an e-document or a program to a definite end-user. In StarForce's solutions we offer to use for binding PCs and optical disks. The aim of copy protection for a developer is to make a protected document unusable without the verification of the selected binding object .For hackers it should be difficult to crack the protection system using analysis and reverse engineering and to overcome the protection.
PDF Protection with PC binding
Fortunately, the Internet has allowed us to develop more user-friendly technologies, one of which is a binding to a PC. This technology is based on the following: an end user gets a Serial Number with his software or e-document copy. A Serial Number acts as a unique identifier of the publisher’s license. When an end-user launches the protected program or document for the first time, he or she enters a Serial Number the protection system initiates a specific sequence of actions. At first, the protection system collects the information about the PC’s hardware parameters. This information is stored on the PC as a hardware profile of which hash function is calculated. This data with the Serial Number are transmitted to StarForce server where the Serial Number is being verified. In the simplest case, the server checks if there is such Serial Number in the database and its activation status. If the validation is successful the user gets an activation key, which contains the hardware profile signature. The activation key is saved on the user's computer. After that the activation is completed. And every time user runs the app or opens the document, the protection system compares hardware profile with the real hardware parameters (small deviations are allowed) as well as with the activation key. If the validation succeeds, you are allowed to run the app or open the document.
The PC binding is much more convenient for end users, because he or she totally ceases to notice the existence of copy protection after activation. The activation is automatic with the Internet connection or manually (e.g. via SMS) if the Internet is not available. The only one inconvenience comes to the user if he wants to change his computer. The problem is that the publisher defines the rules of the activation for his product. Usually publishers give several activations with a single Serial Number but not many. For changing it they can use the following options: to edit a Serial Number, to order the automatic recovery of activations after a certain time or give permission for Serial Number deactivation to activate it on some other computer.
To compare with the disc binding the PC binding method is less convenient for publisher because of the necessity of Serial Numbers delivery. They have to supply every product copy with a unique Serial Number. It is not complicated for online distribution, but it's difficult when disks are used for the product distribution.
The binding of a document to the computer is based on the document activation. The activation should be performed when a protected document is opened for the first time:
- When a document is opened for the first time, the system asks the end user to enter a serial number – a unique string of digits and Latin letters that allows the end user to open the document on the current computer.
- The end user enters the serial number obtained along with the protected document.
- The protection system gathers information about software and hardware parameters of the computer and sends it along with the serial number to the StarForce license management server (Internet connection is required).
- The StarForce license management server checks that the serial number is valid and has not yet been used to open documents on another computer. The server then returns an activation key that contains information about the license (whether printing is enabled, what is the expiration date) and computer hardware parameters.
- The protection system checks whether the activation key corresponds to the hardware and software parameters of the computer and allows the end user to open the document.
- When the end user opens the document next time, the protection system checks whether the activation key corresponds to the hardware and software parameters of the computer and, if the check is successful, allows the end user to open the document.
The customer can specify the following parameters when generating serial numbers:
- Number of activations per serial number.
- Time between activations.
- Activation start date.
- Serial number expiration date.
- Whether periodic license confirmation should be enabled.
- Level of binding to computer that indicates how many changes are allowed in the software and hardware configuration of the computer so that no re-activation is required.
- Regional activation restrictions.
- Whether printing should be enabled for the protected file.
Document protection with optical media binding (CD and DVD)
Before the Internet era, disk binding was the only one adequate method for the identifying of low-cost protection copies. This method was very convenient for publishers, but end users were dissatisfied, because every time they wanted to launch a protected app they had to insert the disk into the drive. In addition, the users had to refer to the publisher to launch the app in case of loss or damage of the protected disk.
The basis of the binding to an optical disc (CD or DVD) is that there are unique geometrical parameters of the data sector location on the disc. The parameters can be determined by measuring the delays of read sector operations. The geometrical parameters are unique for a batch of discs replicated from a single stamper.
Disc check is performed as follows.
- When the end user opens the document (or the executable file), the protection system checks whether the disc with the required label is in the drive. If there is no disc, the system prompts the user to insert it.
- The system measures the geometrical parameters of the disc and compares them with the key written to disc.
- If the parameters correspond to the disc, the document opens; otherwise, an error message is displayed.
If the user does not have a disc from the required batch, the check fails and the document does not open.
The StarForce Content uses implementation of disc binding without the use of the driver.
The last stage of the document protection includes preparing the disc image to be burnt to the disc. The image should contain the key with valid geometrical parameters of the disc. To make the geometrical parameters known during disc image preparing, one of the following methods is used.
- Use StarForce CD-R or DVD-R discs. Geometrical parameters for these discs are known beforehand.
- Order CD-ROM or DVD-ROM discs from the plants that are the partners of StarForce and that can ensure the replication of discs with certain geometry (Keyless Technology).
About StarForce Technologies
StarForce Technologies (www.star-force.com) is a leading vendor of information protection, copy protection and code obfuscation solutions for software, electronic content and audio/video files. Since 2000, StarForce has been successfully developing and implementing its state-of-the-art security solutions, providing copyright and intellectual property protection worldwide. Two of these solutions were transformed into StarForce cloud services: sfcontent.com protects e-Documents against illegal copying and distribution and sfletter.com secures emails.
StarForce is a reliable and responsible Technological Partner for enterprises potentially incurring losses due to cyber-gangs, hackers, software piracy, unauthorized data access and information leaks. StarForce’s customers are Russian Railways, Corel, 1C, Mail.ru, Aeroflot, SUN InBev Russia, AMD Labs, ATC International, MediaHouse, Russobit M, New Disc, Buka, Snowball, 2Play, GFI, CENEGA, Akella, etc.