Cryptology ePrint Archive: Report 2006/105

Tunnels in Hash Functions: MD5 Collisions Within a Minute

Vlastimil Klima

Abstract: In this paper we introduce a new idea of tunneling of hash functions. In some sense tunnels replace multi-message modification methods and exponentially accelerate collision search. We describe several tunnels in hash function MD5. Using it we find a MD5 collision roughly in one minute on a standard notebook PC (Intel Pentium, 1.6 GHz). The method works for any initializing value. Tunneling is a general idea, which can be used for finding collisions of other hash functions, such as SHA-1, 2. We show several capabilities of tunnels. A program, which source code is available on a project homepage, experimentally verified the method.

Revised version of this paper contains the appendix with the description of more tunnels. These tunnels further decrease the average time of MD5 collision to 31 seconds. On PC Intel Pentium 4 (3,2 GHz) it is 17 seconds in average.

Category / Keywords: secret-key cryptography / Hash function, MD5, collision, multi-message modification method, tunnel, tunneling

Date: received 18 Mar 2006, last revised 17 Apr 2006

Contact author: v klima at volny cz

Available format(s): PDF | BibTeX Citation

Note: Revised version of this paper contains the appendix with the description of more tunnels. These tunnels further decrease the average time of MD5 collision to 31 seconds. On PC Intel Pentium 4 (3,2 GHz) it is 17 seconds in average.

Version: 20060417:190029 (All versions of this report)

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