Re: Cohen's paper on byte order

From: Brian Gladman (fake_at_nowhere.org)
Date: 05/08/03 

Date: Thu, 8 May 2003 08:16:23 +0100

"Douglas A. Gwyn" <DAGwyn@null.net> wrote in message
news:3EB9F761.9080009@null.net...
> Brian Gladman wrote:
> > This simply means that Doug doesn't like your notation. But, since you
said
> > it was a bit sequence, 01001111 is fine. In a more formal sense it
might be
> > necesssary to say that the bits will be presented left to right and
numbered
> > left to right starting from 0 but adding such details would apply
whatever
> > notation was adopted.
>
> The problem is that MKS assumes that there is only one way
> to assemble a bit sequence into multibit units (he only
> seems to want to work with octets), and interprets his
> specific method of presenting the bit sequence as inducing
> that assembly, i.e. bitwise big-endian. I.e. he is
> selecting his argument to arrive at a presupposed answer,
> whether through ignorance or intellectual dishonesty.
> Note that in actual bit-serialization practice little-
> endian appears to be more common, so MKS's argument is
> certainly not universally applicable. (As I noted
> previously, big-endian is linguistically more natural,
> while little-endian is numerically more natural.)
>
> > All you are doing here is stating that _you_ will assemble bit sequences
> > into bytes in big-endian order.
> > All that Doug wants, in effect, is that the FIPS should _explicitly_ say
> > that this is what you should do.
>
> No, actually I don't think there is any problem for data
> that is organized as a bit sequence; that fits the FIPS'
> I/O model and its handling is specified clarly enough.
> It is only for *multibit*-organized data that there is a
> bit-ordering issue.

I put it this way because, maybe wrongly, I was taking the view that the
issue is that of how to contruct an _external_ byte array interface on top
of the existing bit sequence one.

I would not support an alternative external interface that bypassed the
current interface since two different interfaces hooked separately into
algorithm internals would have far worse potential interoperability problems
than the problem we are discussing.

   Brian Gladman

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