Windows XP Activation: GAME OVER #

For almost two decades, MSKey Readme1 has heralded the defeat of Windows XP's product activation, not via mere circumvention, but by cracking the encryption algorithm itself.

Based on the even earlier Inside Windows Product Activation: A Fully Licensed Paper2, WindowsXPKg3 launched on Microsoft's GitHub platform four years ago (see update #3 below). While it can generate product keys, the program relies on an external, third-party server to return the Confirmation ID.

In a post last year on the Windows XP subreddit (Windows XP web activation is finally dead…), retroreviewyt shared xp_activate32.exe4, which calculates the Installation ID then generates and optionally applies the corresponding Confirmation ID to activate Windows XP, all offline. Wiping the system and reinstalling Windows XP results in the same Installation ID being assigned by Windows (assuming no change in hardware or product key), thus the same Confirmation ID obtains even in msoobe's standard telephone activation window.

Long considered out of reach, this development bodes well for salvaging old systems even after Microsoft shuts down the activation servers. Given their curious tolerance (even use!) of MAS (hosted on their own platform!), which impacts all modern versions of Windows, perhaps Microsoft will see fit to release an official XP activation tool for posterity.


  1. The apparently oldest extant copy, dated January 18, 2005, is signed "yag". A few months later, it was posted to Tool_Delphi2005 by Alexandre Trevizoli. By 2007, Kevin Hatfield was hosting it, and he claimed copyright by 2008, thereby becoming associated with the document in later years.  

  2. In fact, the paper was released in July 2001, before even Windows XP was released to manufacturing. However, it was kept "a little vague at some points in order not to facilitate the task of an attacker attempting to circumvent the license enforcement supplied by the activation mechanism". 

  3. Elliptic Curve Key Tool is a similar app that does not require recompiling for each combination. 

  4. 18432 bytes with a SHA-256 hash of 5a4bcac5a50eb5113dd6a2f88c35ebdb709c4df8a792c71ad03ea347afaced52 (first seen by VirusTotal on 2020-10-16).


  1. Neo-Desktop has forked WindowsXPKg to include a fix for compiling and running properly under Linux. They are also at work on disassembling xp_activate32.exe.

  2. The purported source code for xp_activate32.exe has been posted to MDL (since deleted) by diamondggg, who referenced such a tool in 2021. See this thread for more information.

  3. On the provenance of WindowsXPKg, Endermanch stated: "This repository is not the original source for the Windows XP Keygen. The original was uploaded to PlanetWPA as part of MSKey 4-in-1 algorithm sources back in early 2000s and was made by z22." The comment has been updated with additional details and, along with his XPKeygen README, is sine qua non for understanding the history and mathematics behind this story.

/windows | Apr 23, 2023

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