Algorithm for unique CD-KEY generation with validation

Question

I am trying to create a unique CD-KEY to put in our product\'s box, just like a normal CD-KEY found in standard software boxes that users use to register the product.

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Answer 1

Generate GUID and catenate a random number to it. GUID is guaranteed to be unique and random number will make it improbable to hit a code accidentally. Just don't modify the GUID in any way or you might compromise the uniqueness.

http://msdn.microsoft.com/en-us/library/aa475087.aspx