Re: [fw-wiz] MD5 x SHA-1

From: John Adams (jna-dated-1039647753.99126a@retina.net)
Date: 12/06/02 

To: Roberto Joćo Lopes Garcia <roberto@mha.com.br>
From: John Adams <jna-dated-1039647753.99126a@retina.net>
Date: Fri Dec  6 18:12:17 2002

On Fri, 6 Dec 2002, Roberto Joćo Lopes Garcia wrote:

> Hi
>
> I need to know which is better as a file hash, that is, to see if a file was modified
>
> MD5 or SHA-1

SHA is slower, MD5 is faster.

For the time being, there hasn't been a successful attack on MD5 (as far
as I can remember.) There have been partial attacks on the individual
round functions of MD5 (using differential cryptanalysis), but not of the
full algorithm.

There also hasn't been a successful attack on SHA.

Both MD5 and SHA are strengethened versions of MD4, with SHA taking more
time than MD5 because the digest length was increased from 128 to 160
bits, and the number of steps per round going from 16 to 20.

Overview of hash functions here:
http://citeseer.nj.nec.com/cache/papers/cs/1811/ftp:zSzzSzftp.cs.uow.edu.auzSzpubzSzpaperszSz1995zSztr-95-09.pdf/bakhtiari95cryptographic.pdf

(check out page 6)

--john 

-- 
J. Adams					http://www.retina.net/~jna
The secret of knowing where you are, is knowing what time it is. -- Anonmyous

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