Section 1. Background. Bitcoin is the original cryptocurrency（这里用了 currency 描述， 而不是 coin、token、asset、commodity 之类。冷知识：在 50 多年前，黄金其实也是一种 currency）. The Bitcoin protocol permanently caps the total supply of bitcoin (BTC) at 21 million coins（强调了固定供应量，看来这个特性还是最吸引人的。精英阶层更能明白稀缺性）, and has never been hacked（比特币从诞生至今，整个网络都没被成功攻破过。盗币、网络 bug 这些不属于 hack 的范畴）. As a result of its scarcity and security, Bitcoin is often referred to as “digital gold”（这里给比特币定性，就是作为一种稀缺、安全的电子黄金存在。鲍威尔也表达过类似的观点）. Because there ...