According to Glenn Greenwald, Edward Snowden has an encrypted insurance file stashed with several trusted people that will be decrypted and released "if anything happens" to him. Modern crypto has lots of ways to accomplish this, including partial key escrow, in which a bunch of encryption keys are distributed to various parties; the individual keys aren't sufficient to decrypt the file, but a quorum of them are. For example, you can release a key to ten people and configure it so that any three can, in combination, unlock the file.
Glenn Greenwald, the Guardian Newspaper journalist Snowden first contacted in February, told the Daily Beast Tuesday that Snowden "has taken extreme precautions to make sure many different people around the world have these archives to insure the stories will inevitably be published." Greenwald added that the people in possession of these files "cannot access them yet because they are highly encrypted and they do not have the passwords." But, Greenwald said, "if anything happens at all to Edward Snowden, he told me he has arranged for them to get access to the full archives."
Greenwald: Snowden's Files Are Out There if "Anything Happens" To Him [Eli Lake/The Beast]