I don't know if it is the state of the art, but there is also Shamir's Secret Sharing: http://en.wikipedia.org/wiki/Shamir's_Secret_Sharing http://en.wikipedia.

I don't know if it is the state of the art, but there is also Shamir's Secret Sharing: http://en.wikipedia.org/wiki/Shamir's_Secret_Sharing http://en.wikipedia.org/wiki/Shamir's_Secret_Sharing There is a nice implementation in Debian called 'ssss'. Edit: nifty demo: http://point-at-infinity.org/ssss/demo.html http://point-at-infinity.org/ssss/demo.html