Security Basics mailing list archives
Re: Re[2]: MD5 algorithm
From: Matt Howard <securityfocus () hattmoward org>
Date: Wed, 24 Mar 2004 10:01:07 -0500
On Tuesday 23 March 2004 12:59 pm, you wrote:
Hello Matt, Quite so. I speak english not well, that's why i used 'realization' instead of 'implementation'
That's okay, as long as what you're saying is understood.
MH> You can find Digest::MD5 on CPAN MH> (http://www.cpan.org) Are you familiar with it? As root, on your PC, run: MH> perl -MCPAN -e shell MH> It will ask some questions and select a mirror, then you can type MH> install Digest::MD5 MH> to get what you're looking for. After it's installed, you can run MH> man Digest::MD5 MH> or MH> perldoc Digest::MD5 But I received only 16,22 or 32-byte hashes. Why not 34-byte hashes? And how can I use Digest::MD5 for it? Or maybe you can show me a script on perl or c/c++ with its implementation.
This is the RFC for MD5 along with a C reference implementation: http://www.fourmilab.ch/md5/rfc1321.html There is a perl example at the top of the documentation for Digest::MD5. MD5 is supposed to produce 128-bit (16-byte) hashes. I'm not really sure why you would be expecting 34 bytes, but there /is/ one thing that people will get bitten on with Digest::MD5. The md5 function produces the hash itself, that is, it returns a 128-bit value that is the MD5 hash (a real packed binary value, not a perl "number"). md5_hex and md5_b64 both call the md5 function and return the character representation of that 128-bit value in the requested base. md5_hex produces the expected output if you're checking against the md5sum tool, or checking md5 hashes posted on a web page. The length of md5_hex data should be 32 bytes, and the length of md5_b64 data should be 22. If you want to see the binary expansion of the md5 function, do this: print unpack("B*", md5($data));
MH> to see the documentation and usage examples. If you have any Perl related MH> questions, you can ask them at Perl Monks (http://www.perlmonks.org). Thanks for link.
-- Matt Howard <mhoward__hattmoward.org> http://hattmoward.org PGP: 2364 B8D1 199C 4DB6 9E23 2409 C10B EC85 29B9 91EE --------------------------------------------------------------------------- Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off any course! All of our class sizes are guaranteed to be 10 students or less to facilitate one-on-one interaction with one of our expert instructors. Attend a course taught by an expert instructor with years of in-the-field pen testing experience in our state of the art hacking lab. Master the skills of an Ethical Hacker to better assess the security of your organization. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html ----------------------------------------------------------------------------
Current thread:
- SHA-1 Hash Paul Kurczaba (Mar 18)
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- Re: Re[2]: MD5 algorithm Matt Howard (Mar 24)
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- Re: Re[2]: MD5 algorithm Matt Howard (Mar 25)
- MD5 algorithm BoI base (Mar 22)