It said the WannaCry ransomware cyber-attack was because the NSA stores cyber-weapons. Ransomware is software that blocks computers until the owner pays money to hackers. The NSA helps keep America’s communications and information systems safe. It also stops cyber-attacks. However, experts say the WannaCry hackers used spying tools from the NSA. Microsoft said governments must wake up to the problem of cyber-weapons. Stealing them is as dangerous as stealing missiles. Microsoft said the WannaCry attack shows why keeping cyber-weapons is a problem. Europe’s police said WannaCry harmed 200,000 computers in 150 countries. It made many problems for Britain’s hospitals. Many operations were cancelled. Experts told people to back up their files because more attacks could come.