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From "Leo Li (JIRA)" <>
Subject [jira] Created: (DIRSERVER-1107) [kerberos] shall not use to generate CRC32 checksum
Date Wed, 05 Dec 2007 07:41:43 GMT
shall not use to generate CRC32 checksum

                 Key: DIRSERVER-1107
             Project: Directory ApacheDS
          Issue Type: Bug
            Reporter: Leo Li

As in RFC3961 [Page 17]: 
6.1.3.  CRC-32 Checksum
This CRC-32 checksum calculates a checksum based on a cyclic
   redundancy check as described in ISO 3309 [CRC] but modified as
   described below.  

The CRC-32 checksum used in the des-cbc-crc encryption mode is
   identical to the 32-bit FCS described in ISO 3309 with two
   exceptions: The sum with the all-ones polynomial times x**k is
   omitted, and the final remainder is not ones-complemented.  ISO 3309
   describes the FCS in terms of bits, whereas this document describes
   the Kerberos protocol in terms of octets.  To clarify the ISO 3309
   definition for the purpose of computing the CRC-32 in the des-cbc-crc
   encryption mode, the ordering of bits in each octet shall be assumed
   to be LSB first.  Given this assumed ordering of bits within an
   octet, the mapping of bits to polynomial coefficients shall be
   identical to that specified in ISO 3309.

And RFC 3961 also gives test data in its Appendix A.5:

RFC 3961         Encryption and Checksum Specifications    February 2005

   internally for such a number is irrelevant; the octet sequence
   generated is what is important.)

   mod-crc-32("foo") =                                     33 bc 32 73
   mod-crc-32("test0123456789") =                          d6 88 3e b8
   mod-crc-32("MASSACHVSETTS INSTITVTE OF TECHNOLOGY") =   f7 80 41 e3
   mod-crc-32(8000) =                                      4b 98 83 3b
   mod-crc-32(0008) =                                      32 88 db 0e
   mod-crc-32(0080) =                                      20 83 b8 ed
   mod-crc-32(80) =                                        20 83 b8 ed
   mod-crc-32(80000000) =                                  3b b6 59 ed
   mod-crc-32(00000001) =                                  96 30 07 77

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