CRC-64

I have obtained the CRC-64 code used in the SWISS-PROT genetic
database:
 ftp://ftp.ebi.ac.uk/pub/software/swissprot/Swissknife/SPcrc.tar.gz

(Thanks go to Henning Hermjakob <hhe@ebi.ac.uk> of the European
Bioinformatics Institute.)  From the README:
 The code in this package has been derived from the BTLib package  obtained from Christian Iseli
<chris@ludwig-alpha.unil.ch>.From his mail:
 
 The reference is: W. H. Press, S. A. Teukolsky, W. T. Vetterling, and  B. P.  Flannery, "Numerical recipes in C", 2nd
ed.,Cambridge University  Press.  Pages 896ff.
 
 The generator polynomial is x64 + x4 + x3 + x1 + 1.

Choosing a good polynomial is considered a black art.  A good tutorial 
on CRC practice is at
 http://www.repairfaq.org/filipg/LINK/F_crc_v3.html

and there's a clear exposition of the theory in Tanenbaum's 
"Computer Networks".  Note that initialization is important, and 
often neglected: one quality to check is, does a block of all zeroes, 
and a zero CRC, come out as an error?

Nathan Myers
ncm@zembu.com