A former CIA contractor for Booz Hamilton and Dell has outed himself as the man who exposed the US government's huge spying plan.
Edward Snowden, 29, said he had thought long and hard before publicising details of PRISM.
He felt the US was building an unaccountable and secret espionage machine that spied on every American.
According to the Guardian, Snowden is holed up in a Hong Kong hotel room on the run from US spooks. The last person who did something like this was immediately arrested and only saw a trial a few years later.
The Washington Post and Britain's Guardian newspaper which he gave the documents to, published his identity on Sunday after he gave his permission.
Snowden said he did not want to live in a society that does these sort of things and where everything anyone does or says is recorded.
The US NSA has built infrastructure that allows it to intercept almost everything and the vast majority of human communications are automatically ingested without targeting.
The exposure of the secret programs has triggered widespread debate within the United States and abroad about the vast reach of the NSA, which has expanded its surveillance programs dramatically in the last decade.
Snowden left his girlfriend in Hawaii without telling her where he was going, said he knew the risk he was taking, but thought the publicity his revelations had garnered in the past few days had made it worth it.
He is worried that the US spooks will come after his family, his friends and his partner.
He said he will not be able to communicate with them for the rest of his life.
Snowden, a former CIA technical assistant, worked for the NSA as an employee of defence contractor Booz Allen Hamilton. He said he had become disenchanted with Obama whom he said had continued the policies of predecessor George Bush.
Three weeks ago, he copied the secret documents at the NSA office in Hawaii where he worked and told his supervisor he needed "a couple of weeks" off for treatment for epilepsy, the paper said. On 20 May he flew to Hong Kong, which he said he chose because "they have a spirited commitment to free speech and the right of political dissent".
Ultimately he hopes that Iceland, which values internet freedom, might grant him asylum.