An MD5 Collision of Two 60-Byte Messages

We present an explicit collision for full MD5 consisting of two distinct 60-byte messages, 120 bytes in total. This is eight bytes less than the two 64-byte messages in the single-block collisions of Xie and Feng (2010) and Stevens (2012). Both inputs are hashed with the standard initialization vector, padding and length encoding specified in RFC 1321. The methodological contribution is a complete differential path compatible with the fixed padding word required by 60-byte messages. It uses a message-difference variant previously listed by Xie, Liu and Feng (2013). Padding-aware path construction is combined with tunnels, neighbourhood refinement, deduplication, priority ordering and subcube pruning. The paper distinguishes measured search rates from model-based estimates of the cost of finding another collision. The deposit includes the paper, both original binary messages, their OpenTimestamps proofs, verification instructions and a SHA-256 checksum manifest. The common digest is 41ef3a4a2f84cdccafe48d14b34d919f and can be checked directly with GNU md5sum or Python's hashlib. The timestamp proofs anchor the messages to Bitcoin block 971910, dated 17 October 2026 at 22:19:38 UTC. They provide evidence of prior existence of the messages, independently of the publication date of this deposit. Search code is not included in this release.