On 24 December 2010, Tao Xie and Dengguo Feng announced the first published single-block (512-bit) MD5 collision. (Previous collision discoveries had relied on multi-block attacks.) For "security reasons", Xie and Feng did not disclose the new attack method. They issued a challenge to the cryptographic community, offering a US$10,000 reward to the first finder of a different 64-byte collision before 1 January 2013. Marc Stevens responded to the challenge and published colliding single-block messages as well as the construction algorithm and sources.
on 24 december 2010 tao xie and dengguo feng announced the first published single-block (512-bit) md5 collision (previous collision discoveries had relied on multi-block attacks) for "security reasons" xie and feng did not disclose the new attack method they issued a challenge to the cryptographic community offering a us$10000 reward to the first finder of a different 64-byte collision before 1 january 2013 marc stevens responded to the challenge and published colliding single-block messages as well as the construction algorithm and sources