http://technet.microsoft.com/en-us/magazine/2008.07.windowsconfidential.aspx

Anyway, even if Microsoft moves from Vigenère to something better, the decryption will always be possible. Windows needs to decrypt and use this all the time – to compile the most used programs list, for example.

A very nice finding indeed.

Congrats from Brazil,

Sandro Süffert

I can also confirm your key is universal, as verified from my installs of Win7beta downloaded from MS(see below)

BWH QNKTEZY FSLMRGX ADUJOPIVC (KEY to test)

D:\Mvxwsvq\jpsvjft.ygs (Exported Win7 Beta – Encrypted UserAssist)
B W H Q N K T E Z Y F S L M R G X A D U J O (Key Match)
C : \ W I N D O W S \ r e g e d i t . e x e (Key Decode)

Nejhbchjs.Baypfcp.PymwpKzpuay (Exported Win7 Beta – Encrypted UserAssist)
B W H Q N K T E Z Y F S L M R G X A D U J O P I V C B W H (Key Match)
M I C R O S O F T . W I N D O W S . M E D I A C E N T E R (Key Decode)

D:\Mvxwsvq\kjekkj32\vgeidpu.lnr (Exported Win7 Beta – Encrypted UserAssist)
B W H Q N K T E Z Y F S L M R G X A D U J O P I V C B W H Q N (Key Match)
C : \ W I N D O W S \ S Y S T E M 3 2 \ M S P A I N T . E X E (Key Decode)

VATU_MMPRCXKTAE (Exported Win7 Beta – Encrypted UserAssist)
B W H Q N K T E Z Y F S L M R (Key Match)
U E M E _ C T L S E S S I O N (Key Decode)

Perhaps it’s an textbook example on how the money is not made by fixing the issues, rather on iteratively improving the situation ever so slightly.

The key was the same for 2 different user accounts on the same machine. I’ll have to do more testing.