Where can I learn about proven methods for sharing cryptographic keys?

Question

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 th

Answer 1

This is easy to implement with error-correcting codes. You could use a command-line tool such as par2 (which is not exactly appropriate for this specific purpose btw, as it generates recovery blocks of varying size). Let's say you have (n+m) voters, and want a quorum of n votes. You generate n private keys K₁∘, K₂, ... Kn, and generate m additionnal ECC blocks Pₓ of the same size. That way any n blocks suffice to reconstitute the cipher K₁∘K₂∘...∘Kn