Good guy Bitcoin developer helps fix bug in competing coin

Proponents of Bitcoin and its competing cryptocurrency Bitcoin Cash, which was created as a “fork” of Bitcoin’s code and history, aren’t exactly in love with each other. Social media channels are full of squabbles over which coin is better and which one is more deserving of the “Bitcoin” name. 

But one Bitcoin Core developer — meaning, a person who develops code for Bitcoin — rose above the petty quarrels and did a big favor for Bitcoin Cash. 

In April, Cory Fields discovered what he describes as a “critical vulnerability” in Bitcoin Cash, and alerted Bitcoin Cash developers which implemented a fix before a malicious actor could exploit it. 

After Fields had noticed a suspicious change in Bitcoin Cash’s code, it took him “less than 10 minutes” to find the bug, which was serious enough to cause a chain split, which (if unintentional) can cause huge damage to a cryptocurrency. 

But it wasn’t just a simple matter of finding the bug and reporting it. “This was a bug in publicly-available, open-source software; any number of people could have already discovered it. There was nothing to stop anyone else from making the same discovery and taking advantage of it before a fix could be fully deployed,” he wrote in a Medium post published Friday. 

“Suppose that I privately disclosed the bug using my name — only for someone else to find it independently and exploit it anonymously the next day,” he wrote. “…billions of dollars could have been lost as a result of this exploit. People have been killed for much less. So not only was anonymity important, I considered it a necessity for my safety.”

Fields decided to report the bug anonymously, and luckily, he was able to reach Bitcoin Cash’s dev team before anyone else had noticed the bug (or, at least, had time to exploit it). 

Bitcoin ABC (the name of Bitcoin Cash’s software implementation) has posted an incident report after the bug was fixed in May, and promised it would take “several actions in order to prevent such an event from occuring again,” as well as set up a formal bug bounty system. 

Fields’ move was lauded by several notable cryptocurrency figures, including Civic CEO Vinny Lingham who tweeted that “Responsible and ethical behavior by everyone in the community, regardless of ideological beliefs, should be applauded.” Vitalik Buterin, the co-founder of Ethereum, retweeted Lingham’s tweet. 

Once the second most valuable cryptocurrency, Bitcoin Cash has dropped to fourth place by market cap according to CoinMarketCap, and is roughly eleven times smaller than Bitcoin. And while there’s still a lot of friction between fans of Bitcoin and Bitcoin Cash, Fields’ example shows that it’s still possible to help each other out to the ultimate benefit of all.