How Clone Protection Schemes Work

One of the methods sometimes employed to enable the illegitimate use of licensed software is machine cloning. Machine cloning involves copying the entire image of one machine (including your software and its legitimate license) and duplicating it to one or more other machines. If there is no way to detect that the new image is running on different hardware than that on which it was originally installed, multiple instances of the software are available even though only a single license was purchased.

As part of the Activation process for a licensed Product, the Sentinel LDK License Manager creates a “fingerprint” of the computer on which the protected software is installed. This fingerprint contains hash values of a number of characteristics of the computer. This fingerprint (referred to as the reference fingerprint) is stored within the secure storage on the computer and is also returned to the Vendor in the C2V file. At the Vendor site, the fingerprint is stored as part of the license information in the Sentinel EMS database.

Each time the end user starts the protected software, the Sentinel LDK License Manager creates a new fingerprint of the computer (referred to as the system fingerprint) and compares it to the reference fingerprint.

If the system and reference fingerprints are identical or sufficiently close (as described in this appendix), Sentinel LDK allows the protected software to operate.

When clone detection is enabled for a Product in Sentinel LDK, the License Manager checks for cloning using the criteria described in this appendix. If cloning is detected, Sentinel LDK disables the license. As a result, the end user is unable to operate the software for which a cloned license has been detected.