Suppose that a group wants to encrypt some information, then share the encryption key among the group members in a way that requires the consensus of the group to decrypt the information. I’m interested in a variety of scenarios where the breadth of consensus ranges from unanimity to an absolute majority. A useful technique can apply to symmetric keys, private keys, or both.
I could take a crack at rolling my own method, as I’m sure many SO members could. But for the purposes of this question, I am interested only in methods that have been widely published and have withstood scrutiny by expert cryptanalysts. Journal citations are good, but interpretation of academic sources are very useful too.
I have always been fascinated by this secret sharing technique. I’ve seen code implementing it on the internet, but have never seen actual applications. Shamir’s secret sharing The wikipedia article links to some actual code, as well as the original academic article.