Smooth prime MD5 collisions

[Weger, B.M.M. de]

Hi Ben,

Looks like this is essentially the same as, or at least very similar to,

what Arjen Lenstra and I did in Section 4 of the full version of our
paper
"On the possibility of constructing meaningful hash collisions for
public keys",
see http://www.win.tue.nl/~bdeweger/CollidingCertificates/ddl-full.pdf.
The proceedings version of this paper (presented at ACISP 2005,
proceedings
in Springel LNCS 3574) skipped that section due to space limitations.

Grtz,
Benne de Weger

=========================================
Technische Universiteit Eindhoven
Coding & Crypto Groep
Faculteit Wiskunde en Informatica
Den Dolech 2
Postbus 513
5600 MB Eindhoven
kamer:  HG 9.84
tel.:   (040) 247 2704, bgg 5141
e-mail: b.m.m.d.weger at tue.nl
www:    http://www.win.tue.nl/~bdeweger
=========================================


  

> -----Original Message-----
> From: owner-cryptography at metzdowd.com 
> [mailto:owner-cryptography at metzdowd.com] On Behalf Of Ben Laurie
> Sent: vrijdag 21 oktober 2005 1:40
> To: Cryptography
> Subject: Smooth prime MD5 collisions
> 
> Inspired by http://www.links.org/?p=12#comments, I have just produced
> this prime:
> 
> D131DD02C5E6EEC4693D9A0698AFF95C2FCAB50712467EAB4004583EB8FB7F
> 8955AD340609F4B30283E4888325F1415A085125E8F7CDC99FD91DBD728037
> 3C5BD8823E3156348F5BAE6DACD436C919C6DD53E23487DA03FD02396306D2
> 48CDA0E99F33420F577EE8CE54B67080280D1EC69821BCB6A8839396F965AB
> 6FF72A7000000AD6BF4FE0D1559E6140208D6D2BA4694335
> 
> which I claim collides (using the well-known alternative block) with a
> number that has the first 26 primes as factors.
> 
> Also, while I was writing this, I got:
> 
> D131DD02C5E6EEC4693D9A0698AFF95C2FCAB50712467EAB4004583EB8FB7F
> 8955AD340609F4B30283E4888325F1415A085125E8F7CDC99FD91DBD728037
> 3C5BD8823E3156348F5BAE6DACD436C919C6DD53E23487DA03FD02396306D2
> 48CDA0E99F33420F577EE8CE54B67080280D1EC69821BCB6A8839396F965AB
> 6FF72A7000000085EDE28444505E3FE8D0F8D68EFF7CF302ECEE5FCCFA78FA
> E6BF0F897957F7CD21
> 
> which collides with 43 primes.
> 
> Code and stuff will follow, but now I'm going to bed. I expect its
> obvious how they are made, anyway.
> 
> Cheers,
> 
> Ben.
> 
> -- 
> http://www.apache-ssl.org/ben.html       http://www.thebunker.net/
> 
> "There is no limit to what a man can do or how far he can go if he
> doesn't mind who gets the credit." - Robert Woodruff
> 
> ---------------------------------------------------------------------
> The Cryptography Mailing List
> Unsubscribe by sending "unsubscribe cryptography" to 
> majordomo at metzdowd.com
> 

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at metzdowd.com