Public key. A cryptographic code that allows a person to receive cryptocurrencies into his or her account. The public key is derived from the private key. In the Bitcoin system, transactions are done using a "pair" of a private and public key.
China announced in September that all cryptocurrency transactions in the country are illegal, effectively putting the brakes on any crypto-related activities within Chinese borders. In the U.S., things are less clear. Federal Reserve Chair Jerome Powell said recently that he has “no intention” of banning cryptocurrency in the U.S while Security and Exchange Commission Chairman Gary Gensler has consistently commented on both his own agency’s and the Commodity Futures Trading Commission’s role in policing the industry.

Among those who called it, hedge fund manager Mark Dow wrote almost exactly a year ago about his decision to short bitcoin after future trading on it first began:
Spot trading means you’re not technically “buying” the cryptocurrency, but instead trading your USD for it through either a market or a limit order. A market order means you agree to trade for the currency at the current market price. A limit order lets you put in a designated price at which you want the trade to occur, and when the currency reaches that price, the trade happens automatically. These orders then incur “maker” (for limit orders) or “taker” (for market orders) fees — though on Binance.US, there’s just a standard 0.1% fee.