Re: Re: Adler-32 Checksum

On Thursday 30 June 2005 17:06, Peter Lei wrote:
> Johnson Walter-CWJ002 wrote:
> > Is there any property that makes the Internet Checksum better at
> > detecting a handlespace inconsistency as compared to a simple XOR of the
> > byte block data which is composed of the pool handle zero padded to a 32
> > bit work boundary and the 32 bit PE Id?
> >
> > Wondering since the Internet checksum will be more computationally
> > expensive.
>
> I'm not sure what your concern is here.  The Internet checksum
> is just the ones's complement of (one's complement sum + carry).
> That's two additional steps over a simple XOR sum.

XOR is computationally cheaper than addition. It works bit-wise and does not 
need a carry. So if the probability of detecting handlespace inconsistencies 
would be the same for the Internet checksum and XOR, XOR would be the 
preferable solution.


Best regards
-- 
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 Dipl.-Inform. Thomas Dreibholz

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