The ride-hailing service Uber revealed that the personal information of 57 million people, customers and drivers, was hacked last year and that the company kept the massive theft secret for more than a year.Uber also paid the hackers $100,000 to delete the stolen data and stay silent about it.The hack, first reported by Bloomberg, was confirmed in a blog post by Uber CEO Dara Khosrowshahi. He said in 2016 the hackers obtained the names, email addresses and mobile phone numbers of 57 million Uber users. The driver's licenses of about 600,000 Uber drivers in the US also were stolen.Khosrowshahi said the company's outside forensics experts see no evidence that the hackers got access to Uber users' trip location history, credit card numbers, bank accounts, Social Security numbers or dates of birth.The CEO said that he had "recently learned" of the massive hack, but he wasn't more specific about what he knew and when.A source close to the company confirmed to NPR that Uber officials paid hackers $100,000 to delete the data and keep the breach secret. The source also said that chief security officer Joe Sullivan and one of his lieutenants were terminated this week.However, Uber declined to confirm how they knew that the data was, in fact, deleted by the hackers.As NPR's Aarti Shahani reported on All Things Considered, the out-going chief security officer Sullivan is the apparent mastermind of the cover up.