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https://issues.apache.org/jira/browse/CODEC-171?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13670435#comment-13670435
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Emmanuel Bourg commented on CODEC-171:
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According to Wikipedia:
http://en.wikipedia.org/wiki/Cyclic_redundancy_check#Commonly_used_and_standardized_CRCs
{quote}Numerous varieties of cyclic redundancy checks have been incorporated
into technical standards. By no means does one algorithm, or one of each
degree, suit every purpose; Koopman and Chakravarty recommend selecting a
polynomial according to the application requirements and the expected
distribution of message lengths.[7] The number of distinct CRCs in use has
confused developers, a situation which authors have sought to address.[5] There
are three polynomials reported for CRC-12,[7] sixteen conflicting definitions
of CRC-16, and six of CRC-32.[8]
The polynomials commonly applied are not the most efficient ones possible.
Between 1993 and 2004, Koopman, Castagnoli and others surveyed the space of
polynomials up to 16 bits,[7] and of 24 and 32 bits,[9][10] finding examples
that have much better performance (in terms of Hamming distance for a given
message size) than the polynomials of earlier protocols, and publishing the
best of these with the aim of improving the error detection capacity of future
standards.[10] In particular, iSCSI and SCTP have adopted one of the findings
of this research, the CRC-32C (Castagnoli) polynomial.{quote}
I didn't know there were several flavors of CRC32. CRC32C is simply a variation
producing different results.
> Add support for CRC32-C
> -----------------------
>
> Key: CODEC-171
> URL: https://issues.apache.org/jira/browse/CODEC-171
> Project: Commons Codec
> Issue Type: Improvement
> Reporter: Brett Okken
>
> Add a java CRC32-C java.util.zip.Checksum implementation.
> There is a PureJavaCrc32C implementation that is part of
> apache-hadoop-common. It would be great to have that more easily consummable
> with far fewer transitive dependencies.
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