BlackHat USA 2011: SSL And The Future Of Authenticity

Caption notes

In this 2011 Black Hat talk, Moxie Marlinspike asks how a browser can confirm who is at the other end of an encrypted connection. He describes the certificate authority model of the time as a trust arrangement that was hard to undo. A client could remove a trusted authority, but that would affect connections to sites relying on its certificates. He proposes two design requirements. Clients should be able to choose whom they trust and revise that choice easily. His Convergence prototype lets clients ask notaries of their choosing which certificates they see from other network paths. He also notes a limitation. If a site legitimately serves different certificates on different paths, that difference alone cannot tell the client whether the connection was intercepted.