[183767] in North American Network Operators' Group
Re: Synful Knock questions...
daemon@ATHENA.MIT.EDU (Valdis.Kletnieks@vt.edu)
Tue Sep 15 16:01:31 2015
X-Original-To: nanog@nanog.org
To: Jake Mertel <jake.mertel@ubiquityhosting.com>
From: Valdis.Kletnieks@vt.edu
In-Reply-To: <CAOhg=RzB-+r5zxq3doWktLdfs1qTgd4yUaQgX9QSdkyg01_oew@mail.gmail.com>
Date: Tue, 15 Sep 2015 16:01:21 -0400
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
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On Tue, 15 Sep 2015 11:54:30 -0700, Jake Mertel said:
> Indeed -- While there are methods that can be used to "pack" a file so that
> it collides with a desirable checksum, that would be nearly impossible to
> do in this scenario.
Small clarification here.
There are known methods to easily produce two files that have the same MD5
hash, but you have no control over the checksum.
There are not (to my knowledge) ways to tweak a file to produce a specified
MD5 hash. MD5 is broken, but not *that* broken (yet). Feel free to point
me at papers if it's been done.
There are ways to easily produce a file with a specified non-crypto-strength
hash like a CRC-32.
So it really matters to be clear on what algorithm is used for the checksum/hash.
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