[nycbug-talk] MD5 Presentation

[Jonathan Vanasco]

On Aug 3, 2006, at 11:56 AM, Steven Kreuzer wrote:

> First, I want to thank everyone who was at last nights meeting. I hope
> everyone enjoyed the presentation and would love to hear some  
> feedback,
> both good and bad.
>
> If anyone is interested, I have posted the slides from the  
> presentation,
> as well as a C program called md5user, which is a small proof of  
> concept
> program that takes a username as an argument, and returns the path to
> where their data would be on the filesystem.

wish i could have made the presentation.

i'm doing nearly the same thing.  just one off

my system maps serials onto directories as such

	abcdefg...z= md5_hex( serial )
	${img_root}/abc/def/ghi/abcdefg...z/

i found the performance of 3x3 hex strings on the directory to be  
great.  i tried 2x2 base64 strings, and it worked fine performance  
wise, but i didn't get the distribution i wanted-- and i didn't like  
dealing with .+ chars

images are served as
	http://imagserver/hash.jpg

and apache translates to a file via mod_rewrite.  i need to recode it  
as a c module one day, so i can tweak a bit more performance.

i tried doing a reverse mapping off of serials too

	123456789 - > 9/98/987/9876/123456789

i think its based off of Benson's law of mathematics.  it works  
well.  i just  decided that i wanted to obfuscate serials to the public.




// Jonathan Vanasco

| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
- - - - - - - - - - - - - - - -
| FindMeOn.com - The cure for Multiple Web Personality Disorder
| Web Identity Management and 3D Social Networking
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
- - - - - - - - - - - - - - - -
| RoadSound.com - Tools For Bands, Stuff For Fans
| Collaborative Online Management And Syndication Tools
| - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  
- - - - - - - - - - - - - - - -