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Single-block collision for MD5


- Single-block collision attack on MD5, Marc Stevens, preprint, 2012, (PDF).

In response to the challenge posted in:
- Construct MD5 Collisions Using Just A Single Block Of Message, Tao Xie and Dengguo Feng, Cryptology ePrint Archive, Report 2010/643, (PDF).


The sources can be downloaded here: md5-1block-collision-attack-sources.tar.bz2.
A windows executable is also available: md5-1block-collision-attack.exe

Example collision

We have found an example colliding message pair: Their MD5 and SHA-1 hashes are:
> md5sum message1.bin message2.bin
008ee33a9d58b51cfeb425b0959121c9 message1.bin
008ee33a9d58b51cfeb425b0959121c9 message2.bin
> sha1sum message1.bin message2.bin
c6b384c4968b28812b676b49d40c09f8af4ed4cc message1.bin
c728d8d93091e9c7b87b43d9e33829379231d7ca message2.bin


For any questions, comments, etc., you can contact me by email: marc AT