Very nice write-up on the lack of collision resistance in the Curl hash function previously used by the #IOTA cryptocurrency. Includes source code for generating collisions, formal proofs, and will be the final say in this debate. github.com/colavitam/curl… The paper is due to Michael Colavita and Garrett Tanzer, both of Harvard University. It appears to be original research performed independently of the paper by Heilman et al. Big thanks to @cybergibbons for bringing this to my attention.