Jenzsch does indeed know the feeling. He wrote the code for the Decentralized Autonomous Organization (DAO), a project launched last April that was a progenitor to the current ICO craze. It was hugely successful, raising over $150 million with its promise to do away with traditional management structures and allow investors to directly dictate how the DAO would allocate its capital and resources. A coding error by Jenzsch meant that a savvy attacker managed to steal some $79 million of those funds. Not only that, it caused the ethereum network to fork, or split, in an attempt to rectify the theft. That’s why we have two versions of ethereum—ethereum and “ethereum classic”—today.

All software has bugs, but when that software is responsible for millions of dollars changing hands through immutable transactions, those coding errors become serious business. It’s one of the problems with trying to build an “unstoppable world computer“—the crux of the ethereum project.