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List:       dm-crypt
Subject:    Re: [dm-crypt] bits vs bytes
From:       Arno Wagner <arno () wagner ! name>
Date:       2020-03-31 9:32:57
Message-ID: 20200331093257.GB6454 () tansi ! org
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On Tue, Mar 31, 2020 at 08:55:32 CEST, Michael Kj=F6rling wrote:
> On 31 Mar 2020 08:43 +0200, from arno@wagner.name (Arno Wagner):
> > Otherwise you would need to multiply by 8 in a lot of places.
> > And you could also use nibbles (4 bit) words (16 bits), =

> > long words (32 bits) or quadwords (64 bits) as "units". The =

> > byte is not really specuial.
> =

> And let's not forget that at the time when many long-lasting
> encryption algorithms (DES, RSA, anyone?) were being designed, it
> still wasn't an open-and-shut case whether even a digital binary
> computer would represent data in 8-bit chunks or not. Octal was still
> big in the late 1970s.

Hehehe, yes. That would be 3-bit units...

Anyways, while SI has no unit for "information", as it is not
a physical thing, Information Theory typically uses "bit" as =

base unit. But there are apparently also people that use "nat" =

(base e) and "decimal digit" (base 10) in Information Theory. =

So we are fortunate they usually use something binary in the =

first place!

Hence "bit" is basically the most common denominator for the
different fields involved and also the most simple one =

which nicely satisfies KISS.

For even more confusion: =

  https://en.wikipedia.org/wiki/Binary_prefix
Not only do SI and IEC disagree, but at least with different =

prefixes, apparently JEDEC does something even worse and =

redefines existing prefixes!

Regards,
Arno

-- =

Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno@wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
A good decision is based on knowledge and not on numbers. -- Plato

If it's in the news, don't worry about it.  The very definition of =

"news" is "something that hardly ever happens." -- Bruce Schneier
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