The coin hit a three-week low after President Joe Biden’s nominee to lead the treasury, Janet Yellen, said she would suggest that lawmakers rein in Bitcoin due to its use in illegal activities. “A double spend is when someone is able to spend the same bitcoin twice,” adds the article. “It is a feared and dire scenario for the digital asset, and the blockchain was thought to have solved the issue when Satoshi Nakamoto published the Bitcoin white paper in 2009.”