Secure Bindings of SAML Assertions to TLS Sessions

In recent research work, two approaches to protect SAML based Federated Identity Management (FIM) against man-in-the-middle attacks have been proposed. One approach is to bind the SAML assertion and the SAML artifact to the public key contained in a TLS client certificate. Another approach is to strengthen the Same Origin Policy of the browser by taking into account the security guarantees TLS gives. In this paper, we present a third approach which is of further interest beyond IDM protocols: we bind the SAML assertion to the TLS session that has been agreed upon between client and the service provider and thus provide anonymity of the browser.