Proof-of-work requires specialized computing equipment, like high-end graphics cards to validate transactions by solving highly complex math problems. Validators gets rewards for each transaction they confirm. This process requires a ton of energy to complete. On Thursday, Kraken, a crypto trading company, agreed to end staking and pay a $30 million fine to the agency, which said offering the product amounted to selling unregistered securities. The market is taking the issue seriously. Coinbase