[501] in Kerberos
Re: CBC vs PCBC
daemon@TELECOM.MIT.EDU (Stuart Levy)
Wed Sep 7 19:45:51 1988
From: "Stuart Levy" <slevy@UC.MSC.UMN.EDU>
To: jon@BITSY.MIT.EDU, ota+@ANDREW.CMU.EDU
Cc: kerberos@ATHENA.MIT.EDU
Speaking of key byte order independence, that's something that seems to be
missing from the des_crypt(3) man page. The DES standard specifies keys and
data blocks in terms of 64-bit strings but doesn't talk about arranging them
on octet arrays as far as I can see. And des_crypt doesn't mention anything
about the format its routines use.
All the DES implementations I've seen -- including Kerberos' -- assign
DES bit 1 = 0x80 in the first byte, ..., DES bit 64 = 0x01 in the last byte
but it would be nice if that were written down. It would be pretty natural
to go the other way around and say DES bit <i> has significance 2 ** (i-1),
yielding bit 1 = 0x01 in the first byte, ... bit 64 = 0x80 in the last byte
on little-endian machines.
I'm surprised this hasn't caused more trouble.
Stuart Levy, Minnesota Supercomputer Center
slevy@uc.msc.umn.edu
