On 2007-05-10 00:23:50 +0200, Johannes Schindelin wrote:

quoted text
> I was not aware originally, that no arithmetic is involved in SHA-1
> computation.
>
> If you store large integers, it makes tons of sense to follow the
> endianness, especially if you do _both_ boolean and integer
> operations on them.

Actually, if you take a look at

  http://en.wikipedia.org/wiki/Sha1#SHA-1_algorithm

you'll see that in addition to an unholy mess of bitwise operations,
it does do some additions, on 32-bit big-endian words according to the
article.

But thinking of them as addition gives you the wrong mental picture;
they're simply one of many ways for a standard processor to mix bits
efficiently as far as SHA-1 is concerned. The algorithm is specified
as yielding a 160-bit binary blob, and can and should be thought of as
a black NSA-certified box with "warranty void if this seal is broken"
stickers. (Unless you're the one implementing it, of course. But then
you know what you're doing.)

-- 
Karl Hasselstr