How do product keys work?

[Linda B]

How does Windows (or Photoshop or Half-Life or any other program in the
universe) know if any given product key is good or not? Is there some huge
encrypted database of all the valid product keys stored on the installation
media? Is there some algorithm performed on the key, matched against some
encrypted solution? How does the program know the difference between a
valid OEM key and a valid retail key, or the difference between a trial key
and a full-functioning key?

I only ask out of curiosity, and thought someone here might have a good
explanation -- I've wondered this many, many times, and have just never
bothered to ask. The apathy ends now!

 

[Dave Patrick]

This may help.

http://www.microsoft.com/piracy/activation_how.mspx

--
Regards,

Dave Patrick ....Please no email replies - reply in newsgroup.
Microsoft Certified Professional
Microsoft MVP [Windows]
http://www.microsoft.com/protect

:
| How does Windows (or Photoshop or Half-Life or any other program in the
| universe) know if any given product key is good or not? Is there some
huge
| encrypted database of all the valid product keys stored on the
installation
| media? Is there some algorithm performed on the key, matched against some
| encrypted solution? How does the program know the difference between a
| valid OEM key and a valid retail key, or the difference between a trial
key
| and a full-functioning key?
|
| I only ask out of curiosity, and thought someone here might have a good
| explanation -- I've wondered this many, many times, and have just never
| bothered to ask. The apathy ends now!
|
| --
| LB
|
|
|
|
|

 

[R. McCarty]

Good Question - It must be some type of algorithm that takes the
5 sequences of 5 characters (1-9, A-Z) and then through some very
complicated math determines that the key is valid.
Since certain product type keys won't work in other members of
the product line, there is probably a pre-check for correct structure
that automatically throws out incorrect product type keys.
Since the Warez community (?), uses KeyGens to construct valid
keys it must be mathematical.
With a 25 character string, using 35 variables for each member of
the string the possible valid combinations are extremely high.
The coding for keys is probably like Doc Pemberton's original Coke
formula - locked in a safe somewhere.
From all the keys I track for customers, the only thing I've ever
noticed about XP keys are the re-occurring use of the letter Q, the
numeral 9 and the lack of the number 1.

 

[Linda B]

This is actually an intereesting FAQ, but doesn't quite address my
question -- I was wondering how the installer itself knows whether or not a
key is valid, completely independent of any outside verification. I mean I
don't have to be connected to the internet or on the phone with someone in
order for the installer to know if they key is valid or not, so there must
be some internal verification mechanism

 

[Linda B]

Since the Warez community (?), uses KeyGens to construct valid

keys it must be mathematical.

Good point, I hadn't thought of that.

 

[Steve Shattuck]

How does the program know the difference between a valid OEM key

and a valid retail key, or the difference between a trial key
and a full-functioning key?

The key is parsed in a mathematical calculation that yields a new number
that can be validated as correct or incorrect without access to a database
of valid numbers. In the good old days, these keys were not particularly
sophisticated, and easily decoded (cracked). For example, the key for the
first version of MS Office that came with a key, the only thing required was
that the last 7 digits be evenly divisible by 3. When I was in computer
support, I simply entered 3333333 for the last 7 digits, and didn't bother
to carry around the license database for each computer.

Of course, over time the calculation has become much more sophisticated, but
I'm betting someone has cracked the XP calculation by now.

 

[Alex Nichol]

How does Windows (or Photoshop or Half-Life or any other program in the
universe) know if any given product key is good or not? Is there some huge
encrypted database of all the valid product keys stored on the installation
media? Is there some algorithm performed on the key, matched against some
encrypted solution?

That is what is done - in Windows at any rate. The initial Setup
program puts the Key through a calculation which comes up with 'Is this
acceptable for this windows version and CD series?'. If OK, it then
generates the simpler numeric Product ID (to be seen at Control Panel
System ) which is used in registration (if done) and Activation

 

[Linda B]

Thanks for satisfying my curiosity, everyone. At some point I'd love to
know just how that calculation is done, but I suppose I'll have to wait
until Billy G. & Co. are willing to divulge that information.

 

[Marty Fried]

Back on Tue, 15 Feb 2005 15:56:14 -0700, while hiding out in
microsoft.public.windowsxp.general,"Dave Patrick"

This may help.

http://www.microsoft.com/piracy/activation_how.mspx

Actually, activation is different than the product key she is asking about;
the key does not require an internet connection.

The key is usually a number or series of numbers that can be put through a
series of mathematical operations, and either the result is checked to be
legal, or the intermediate results are checked along the way. The key may
also determine certain features that will get activated (for some products).

 

[NobodyMan]

The key is parsed in a mathematical calculation that yields a new number
that can be validated as correct or incorrect without access to a database
of valid numbers. In the good old days, these keys were not particularly
sophisticated, and easily decoded (cracked). For example, the key for the
first version of MS Office that came with a key, the only thing required was
that the last 7 digits be evenly divisible by 3. When I was in computer
support, I simply entered 3333333 for the last 7 digits, and didn't bother
to carry around the license database for each computer.

Of course, over time the calculation has become much more sophisticated, but
I'm betting someone has cracked the XP calculation by now.

Yes, the XP codes have been cracked. There are keygens out there for
XP Pro VLK keys, and I think the OEM keys. Not sure about full
retail, upgrade, or Home edition keys.

 

[Alex Nichol]

Thanks for satisfying my curiosity, everyone. At some point I'd love to
know just how that calculation is done, but I suppose I'll have to wait
until Billy G. & Co. are willing to divulge that information.

That will be highly secret. Though some of the hackers managed to make
key generators that give an acceptable key, I think that is result of
trial and error

 

[OShah]

That will be highly secret. Though some of the hackers managed to make
key generators that give an acceptable key, I think that is result of
trial and error

On my site I have a product key finder that comes with source code. It
contains the algorithm to convert the Product ID back into a product key (the
reverse of what you want).

If you knew C++ and Advanced Algebra, you may be able to reverse that
algorithm and turn my product key finder into a keygen.



The code explains why there is a lack of 0/1's, vowels and L in the product
key, (and why Q and 9 is so common).


For Windows activation, that's an entirely different story (Activation is
internet based, hashed by your hardware). Don't get started on Half
Life/Photoshop!



--
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http://hometown.aol.co.uk/shexec32/

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-> Do not report errors for these programs:

Acrobat.exe
waol.exe

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