[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

RE: [TSVN] Impact of GUID change?

From: Amir Kolsky <amir_at_xpandsoft.com>
Date: 2005-01-09 13:53:53 CET

MD-5 Hashes are not random, in the sense that they are generatable. However
they are what's mathematically known as one way functions - this means that
you can not determine the source of the hash by looking at the hash.

What's random is the distribution...

 Amir Kolsky
XP& Software
 

>-----Original Message-----
>From: SteveKing [mailto:steveking@gmx.ch]
>Sent: Friday, January 07, 2005 9:19 PM
>To: dev@tortoisesvn.tigris.org
>Subject: Re: [TSVN] Impact of GUID change?
>
>Will Dean wrote:
>> Well, I didn't believe you, because I had a quote of Larry Osterman
>> (sp?) saying that the new GUI algorithm was just an MD5 hash of the
>> old-style GUID.
>
>Never heard of that. But if you read about how hashes are
>built, you will discover that a hash has to be as random as
>possible (not in the sense that a hash of something will
>change, but if you change one byte of the source the result
>hash has to be as random as possible from the previous hash).
>Ok, not a very mathematical description, but I hope you get the point.
>
>> But not really believing anyone, I've just stepped through
>UuidCreate,
>> and it does indeed just generate a pseudo-random number (I'm
>not sure
>> how it seeds this).
>>
>> So I'll concede, your pseudo random numbers are probably
>just as good
>> as anyone else's!
>
>I've just read that in several places in the MS newsgroups
>that the GUIDs are created randomly. Not sure how exactly it
>is done though.
>
>Stefan
>
>--
> ___
> oo // \\ "De Chelonian Mobile"
> (_,\/ \_/ \ TortoiseSVN
> \ \_/_\_/> The coolest Interface to (Sub)Version Control
> /_/ \_\ http://tortoisesvn.tigris.org
>
>---------------------------------------------------------------------
>To unsubscribe, e-mail: dev-unsubscribe@tortoisesvn.tigris.org
>For additional commands, e-mail: dev-help@tortoisesvn.tigris.org
>

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tortoisesvn.tigris.org
For additional commands, e-mail: dev-help@tortoisesvn.tigris.org
Received on Sun Jan 9 13:43:35 2005

This is an archived mail posted to the TortoiseSVN Dev mailing list.