Digital currency exchanges often suffer DDoS attack. Just before the site became inaccessible, if there was a large sell order, it could trigger a cascade of liquidations. On May 7 2007, Kraken was attacked. The Ethereum price went from around $90 to a bottom of $26, in effect liquidating everyone with a long position. On June 21 2007, Coinbase was attacked. Ethereum’s order book at Coinbase’s GDAX was completely obliterated as someone sold millions of dollars worth of Ethereum at market price, leading to a cascade of 800 stop orders and margins, sending Ethereum’s price to ten cent.

Circuit breaker is used to prevent market crashes. It prevents both speculative gains and dramatic losses within a small time frame. As a result of being triggered, circuit breakers stop trading for a small amount of time.

For example, 10% change in value within a 5-minute window will trigger a trading stop for 5 minutes.