Re: JFK nit

["Steven M. Bellovin" <smb@research.att.com>]

In message <200205101806.g4AI6FaS002134@kebe.east.sun.com>, Dan McDonald writes
:
>Sorry if this has been repeated before...
>
>> 4.1  Structure
>> 
>>    Each message is a string of tag-length-value elements concatenated
>>    together.  Tags are one octet.  Lengths are two octets, and specify
>>    the number of octets of the value.  Values are always integral
>>    numbers of octets.  All octets are in big-endian order.
>
>
>Ewwww.  This is not a good choice.  Modern machines work better with aligned
>data!  Say you have two nonce tags in a row (Ni, followed by Nr).  Say they
>start nicely on byte 0x10...
>
>
>	0x10	<Ni tag>
>	0x11	<Ni len msb>
>	0x12	<Ni len lsb>  == 8 bytes
>	0x13	Ni msb
>	...
>	0x1a	Ni lsb
>	0x1b	<Nr tag>
>
>I can load the whole nonce into a register, but I can't, because it starts at
>the byte-only-boundary of 0x13.
>
>JFK authors, please address this problem.  If you want to discuss matters of
>bit-twiddling import, let me know!
>

We're completely agnostic about details like that.  "send text".

		--Steve Bellovin, http://www.research.att.com/~smb
		Full text of "Firewalls" book now at http://www.wilyhacker.com