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ReFox 8
Message
From
19/01/2002 17:24:11
 
 
To
16/01/2002 16:48:26
General information
Forum:
Visual FoxPro
Category:
Third party products
Title:
Miscellaneous
Thread ID:
00604283
Message ID:
00607359
Views:
32
Level II branding changes a few bits that control the pseudo random number generator that drives VFP's obfuscation scheme (XOR with a pseudo-random byte stream). You should be able to see the changed parameters if you diff a branded runtime DLL against an unbranded one.

Thus, to decompile such an APP a cracker would need the branded runtime DLL in order to extract the modified PRNG parameters. OTOH the total entropy is about 40 bits or less, so brute-forcing the parameters takes less than a minute on a P3 class machine. May be less hassle than trying to locate both the branded runtime and a matching unbranded version, and then to find out where exactly the parameters are stored in that version of the runtime.
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