The Windows XP's product activation encryption algorithm has recently been "cracked", and a software implementation that emulates the telephone activation question / response procedure is available. This technically allows one to activate new XP installations, safely and securely, without a crack, offline even though Microsoft has turned off all the activation servers.

This is particularly relevant for those with older scientific equipment that relies on an XP computer. I think these would usually be sold with quite permissive licences, allowing one to change the computer freely and reinstall Windows XP. However it would appear that using this software could be "circumventing a technological measure or access control technology", and therefore illegal in the US.

Is this a reasonable interpretation of the law? Is there some exception that would apply in this case? Is there a way to utilise this application legally in such a situation?

  • 1
    Have you considered asking Microsoft for permission to circumvent their access control measures in this way?
    – nick012000
    May 26, 2023 at 11:34
  • "No cause they might say no." Jun 25, 2023 at 18:31

1 Answer 1


The DMCA applies if the item being copied is protected by some mechanism that prevents copying.

Just because that mechanism isn't very strong, doesn't mean DMCA doesn't apply. For example, there is a mechanism designed in the 1980s to prevent DVDs from being copied. This was cracked some time later by clever mathematical methods; today your home computer would be powerful enough to crack it using brute force without having to do anything clever. That doesn't mean it's not protected; it is, and therefore it is covered by the DMCA.

Same here. The product activation algorithm is protected. Just because someone broke that protection doesn't mean it's not protected. This is like a burglar buying a new tool to open your locked front door, just because the burglar has this tool doesn't mean your front door isn't locked. So here as well DMCA still applies.

(I assume this has been done because copy protection can have bugs and prevent legitimate users from copying, so they made the legal protection strong so that companies are not forced to create the strongest possible copy protection, which might hurt their customers. )

  • How could DVDs be encrypted in the 1980s when they weren’t invented until 1995?
    – SegNerd
    May 26, 2023 at 16:18
  • Probaby Mixup of CD and DVD
    – Trish
    Jun 25, 2023 at 22:03

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