Chaining Secure Channels (Technical Report)

Abstract

Security architectures often make use of secure transport protocols to protect network messages: the transport protocols provide secure channels between hosts. In this report we examine the possibilities for chaining secure channels. We present a surprising theorem that shows that, in some cases, two channels can be chained through a proxy to produce a stronger channel. We also show that the channel established through a proxy is at least as strong as the greatest lower bound of the channels established to and from the proxy.