How to Keep a Secret Alive: Extensible Partial Key, Key Safeguarding, and Threshold Systems

Abstract

Partial key, key safeguarding, and threshold techniques appear to be another example of similar good ideas springing up in several places at nearly the same time — each with a different name and associated terminology. The use of partial key techniques actually appeared in print first in a technical report [Chaum 79] before the key safeguarding techniques were presented at a conference [Blakley 79], and before the threshold schemes were submitted for publication [Shamir 79]. (In fact the author received comments on the technical report from Shamir, along with a draft of the threshold scheme.)