On Sat, Jun 02, 2001 at 07:46:28AM +0200, Poul-Henning Kamp wrote:
> In message <[EMAIL PROTECTED]>, Spike Gronim writes:
>
> > I understand the literal meaning of /usr/src/lib/libcrypt/crypt-md5.c,
> >and the algorithm it uses to create it's output. However, I do not understand
> >the design criteria or functional purpose of several elements of the process.
>
> At the time the MD5 hash was written we could not use anything DES based
> due to ITAR.
>
> The design criteria was to get a strong, preferably stronger than DES,
> password encryption, which would make brute force attacks very much
> harder.
[snip]
>
> The overall MD5 chewing code were done to try to make the algorithm
> unsuitable for hardware implementation (MD5 is already pretty bad
> for that) the various unlinear steps would make it practically
> impossible to do a hardware implementation of anything but the basic
> MD5: you would still need to iterate through it.
Ah, I hadn't considered that. That pretty much answers my question.
>
> I don't know enough about cryptographic math to argue that this
> algorithm is perfect or even "good". I know it to be better than
> the DES things, and infinitely better than the scrambler we had
> to fill the hole for DES at the time.
>
> In light of this theoretical backing, I introduced the $1$ marker,
> which allows the algorithm to be replaced in a backwards compatible
> way (as already done by OpenBSD).
>
> --
> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> [EMAIL PROTECTED] | TCP/IP since RFC 956
> FreeBSD committer | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
--
--Spike Gronim
[EMAIL PROTECTED]
"Oh yes? An obscene triangle which, has more courage than the word."
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