A [new result][1] shows how to generate *single block* MD5 collisions, including an example collision: [Message 1][2] [Message 2][3] > md5sum message1.bin message2.bin > 008ee33a9d58b51cfeb425b0959121c9 message1.bin > 008ee33a9d58b51cfeb425b0959121c9 message2.bin There is an earlier example of a single block collision, but the technique for generating it was not published. [1]: https://marc-stevens.nl/research/md5-1block-collision/ [2]: https://marc-stevens.nl/research/md5-1block-collision/message1.bin [3]: https://marc-stevens.nl/research/md5-1block-collision/message2.bin