Hi Eric, I was hoping you could shed some light on the particular CRC in use by Win32 executables. I found the following reference, but my eye is not trained to spot CRC32 flavors based on tables... By the way, this information _IS NOT_ contained in Microsoft's PE Specification.
http://www.powerbasic.com/support/forums/Forum2/HTML/000003.html Jeff On Jun 9, 9:47 am, Eric Hughes <[EMAIL PROTECTED]> wrote: > At 03:15 PM 6/8/2007, you wrote: > > >Is this true for what the authors are decribing (forgive my ignorance)? > > >'ForwardCRC': > >|-------------------> > > >'ReverseCRC': > ><-------------------| > > In this case, it's dependent upon the file length. > > Recall how aCRCworks. For a bit stream b_i, treat the b_i as > coefficients of a polynomial P(x). TheCRCvalue is P(x) modulo p(x). Let > N be the file length. Running the file in reverse is equivalent to the map > b_i --> b_{ N - 1 - i } > This has the same effect as > P(x) -> X^{ N } * P(1/x) > > There are more details, but that's the essence of it. > > Eric --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [EMAIL PROTECTED] More information about Crypto++ and this group is available at http://www.cryptopp.com. -~----------~----~----~----~------~----~------~--~---
