[18718] in cryptography@c2.net mail archive
RE: Smooth prime MD5 collisions
daemon@ATHENA.MIT.EDU (Weger, B.M.M. de)
Fri Oct 21 15:23:04 2005
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Fri, 21 Oct 2005 18:11:02 +0200
From: "Weger, B.M.M. de" <b.m.m.d.weger@TUE.nl>
To: "Ben Laurie" <ben@algroup.co.uk>,
"Cryptography" <cryptography@metzdowd.com>
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
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Technische Universiteit Eindhoven
Coding & Crypto Groep
Faculteit Wiskunde en Informatica
Den Dolech 2
Postbus 513
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kamer: HG 9.84
tel.: (040) 247 2704, bgg 5141
e-mail: b.m.m.d.weger@tue.nl
www: http://www.win.tue.nl/~bdeweger
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=20
> -----Original Message-----
> From: owner-cryptography@metzdowd.com=20
> [mailto:owner-cryptography@metzdowd.com] On Behalf Of Ben Laurie
> Sent: vrijdag 21 oktober 2005 1:40
> To: Cryptography
> Subject: Smooth prime MD5 collisions
>=20
> Inspired by http://www.links.org/?p=3D12#comments, I have just =
produced
> this prime:
>=20
> D131DD02C5E6EEC4693D9A0698AFF95C2FCAB50712467EAB4004583EB8FB7F
> 8955AD340609F4B30283E4888325F1415A085125E8F7CDC99FD91DBD728037
> 3C5BD8823E3156348F5BAE6DACD436C919C6DD53E23487DA03FD02396306D2
> 48CDA0E99F33420F577EE8CE54B67080280D1EC69821BCB6A8839396F965AB
> 6FF72A7000000AD6BF4FE0D1559E6140208D6D2BA4694335
>=20
> which I claim collides (using the well-known alternative block) with a
> number that has the first 26 primes as factors.
>=20
> Also, while I was writing this, I got:
>=20
> D131DD02C5E6EEC4693D9A0698AFF95C2FCAB50712467EAB4004583EB8FB7F
> 8955AD340609F4B30283E4888325F1415A085125E8F7CDC99FD91DBD728037
> 3C5BD8823E3156348F5BAE6DACD436C919C6DD53E23487DA03FD02396306D2
> 48CDA0E99F33420F577EE8CE54B67080280D1EC69821BCB6A8839396F965AB
> 6FF72A7000000085EDE28444505E3FE8D0F8D68EFF7CF302ECEE5FCCFA78FA
> E6BF0F897957F7CD21
>=20
> which collides with 43 primes.
>=20
> Code and stuff will follow, but now I'm going to bed. I expect its
> obvious how they are made, anyway.
>=20
> Cheers,
>=20
> Ben.
>=20
> --=20
> http://www.apache-ssl.org/ben.html http://www.thebunker.net/
>=20
> "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
>=20
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>=20
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