Secrets by KM Peterson
From the description of the April 2013 BBLISA meeting at http://www.standalone-sysadmin.com/bl...
KM Peterson's "second talk was on Shamir's Secret Sharing Scheme, aka 'SSSS'. The idea behind this crypto tech is that you have a secret which you want to ensure can only be recovered by the collaboration of a minimum number of involved people - say three of your team of five. You encrypt the plaintext and generate as many keys as people you have, and tell the app how many should be required to release the information. To pull the data out, you provide any of the generated keys, as long as the number of different keys meets the minimum determined when the data was encrypted."