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Inconsistencies/Problems I have seen...


I've found the following in the past week (I don't mean to pick on you,
Dan, it is just that I'm knee deep in coding ISAKMP right now, and your
document needs to be referred to a lot):

IKE Appendix B:

   The key for DES-CBC is derived from the first eight (8) non-weak and
   non-semi-weak (see Appendix A) bytes of SKEYID_e. The IV is the first
   8 bytes of the IV material derived above.

Does this mean that if bytes 1-8 are weak, we look at bytes 2-9 or bytes
9-16?  If we have more weak keys than SKEYID_e has bytes, what do we
look at next?

This whole section on key generation needs to be cleaned up.  It makes
certain assumptions about prf or hash output sizes which might not
necessarily correct.  Please pick the correct text from my previous
email and match it with the following type of change in the section
describing key derivation:

   The key for DES-CBC is derived from the first eight (8) non-weak and
   non-semi-weak (see Appendix A) bytes of SKEYID_e.  (Using bytes n+8
   through n+16 in the event that bytes n through n+7 are weak).  If
   SKEYID_e does not contain enough keying material for this operation,
   the first eight non-weak bytes of the extended key material described
   above are used. The IV is the first 8 bytes of the IV material
   derived above.

or

   The key for DES-CBC is derived from the first eight (8) non-weak and
   non-semi-weak (see Appendix A) bytes of the keying material mentioned
   above. (Using bytes n+8 through n+16 in the event that bytes n
   through n+7 are weak).  The IV is the first 8 bytes of the IV
   material derived above.

ben