Oblivious key escrow

Abstract

We propose a simple scheme, based on secret-sharing over large-scale networks, for assuring recoverability of sensitive archived data (e.g., cryptographic keys). In our model anyone can request a copy of the archived data but it is very difficult to keep the existence of a request secret or to subvert the access policy of the data “owner.” We sketch an architecture for a distributed key escrow system that might be suitable for deployment over very large-scale networks such as the Internet. We also introduce a new cryptographic primitive, oblivious multicast, that can serve as the basis for such a system.