Last month, Ethan Heilman, Tadge Dryja, Madars Virza, and I took a look at IOTA, currently the 8th largest cryptocurrency with a $1.9B market cap. In its repositories on GitHub, we found a serious vulnerability — the IOTA developers had written their own hash function, Curl, and it produced collisions (when different inputs hash to the same output). Once we developed our attack, we could find coll