SHA1/MD5 assembler optimization for AMD64
lazarus / 64-FPC development

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Pasha1st · 2017-02-24 16:09

I've made assembler optimized version for SHA1/MD5 routines for AMD64
based on i386 code. How can I commit them?

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balazsszekely · 2017-02-24 16:40

Here: http://bugs.freepascal.org/view_all_bug_page.php

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Thaddy · 2017-02-24 19:01

Should not be accepted without discussion.
Both algorithms are purely of academical historical  interest.
https://en.wikipedia.org/wiki/SHA-1#SHA-0
https://en.wikipedia.org/wiki/MD5

It would only add confusion to users that do not understand the above
and may actually use them.

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BeniBela · 2017-02-24 19:33

It would be as deprecated as  using a non-utf8 encoding like latin1

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Pasha1st · 2017-02-25 10:06

http://bugs.freepascal.org/view.php?id=31444
I know that md5 and sha1 are considered as weak hashes now.
In my current task I need to "reverse" sha1 hashes, and I wondered why
32-bit build was much faster than 64-bit one.

BTW that's so bad that there is no sha2 hashes in FPC packages, I'll
try to implement them later.

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marcov · 2017-02-25 14:02

Quote from: Thaddy on February 24, 2017, 08:01:05 pmShould not be
accepted without discussion.
Both algorithms are purely of academical historical  interest.

In a security context. But nobody said this was a security context.

E.g. I use it for simple deduplication of blocks of measurement data.
Nothing wrong with that. I haven't seen sensors for sale that craft
blocks specifically to create MD5 hash collisions.

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Thaddy · 2017-02-25 15:29

There are several published sha1 duplicate hashes available on the
web. Also known as collisions..
To prove (also for educational purposes) You can simply copy those and
their source and prove that they indeed are collisions.
That means you have a Popper's falsification and is philosophically
sound proof. As opposed to verification.

https://en.wikipedia.org/wiki/Falsifiability