Inside Windows Product Activation

The Installation ID

We focused our research on product activation via telephone. We did so, because we expected this variant of activation to be the most straight-forward to analyze.

The first step in activating Windows XP via telephone is supplying the call-center agent with the Installation ID displayed by msoobe.exe, the application that guides a user through the activation process. The Installation ID is a number consisting of 50 decimal digits that are divided into groups of six digits each, as in


In this authentic Installation ID we have substituted digits that we prefer not to disclose by 'X' characters. If msoobe.exe is invoked more than once, it provides a different Installation ID each time. In return, the call-center agent provides a Confirmation ID matching the given Installation ID. Entering the Confirmation ID completes the activation process.

Since the Installation ID is the only piece of information revealed during activation, the above question concerning the information transmitted during the activation process is equivalent to the question: "How is the Installation ID generated?"

To find an answer to this question, we trace back each digit of the Installation ID to its origins.