The U.S. Federal Bureau of Investigation has charged four people for their involvement in a massive hack of Yahoo that affected half a billion accounts. Yahoo said hackers had stolen personal data on more than 500 million users during an attack in late 2014. The stolen data included names, email addresses, telephone numbers and hashed passwords. The FBI said that group was the Russian Federal Security Service, the FSB, and it identified agents Dmitry Dokuchaev and Igor Sushchin as leaders of the attack.”]