Provable Security - How I learned to stop worrying and love the backdoor
59:05 · 35C3: Refreshing Memories · 1080p · 2018-12-29
Modern cryptography is based on security-proofs. We will demonstrate how these work, why they are desirable and what their limitations are. <p>Even the use of secure primitives like AES or RSA does not guarantee that the end-result is secure as well. In recent years breaks of modern primitives have in fact become exceedingly rare, yet stories like the KRACK-attack or ROBOT keep appearing.</p> <p>The obvious answer to these problems would be to proof that our protocols are secure. While that may sound great in theory, there are many issues as well:</p> <ul> <li>Proving (almost) anything secure, would require to solve a millennium-problem.</li> <li>Given the above, assumptions are required; but which assumptions are reasonable?</li> <li>The word “secure” may seem intuitive, but can we formally define it? And can something be <em>too</em> secure?</li> <li>Idealizing primitives can solve many problems, but what about over-idealizations?</li> <li>Can backdoors be necessary to prove security?</li> <li>A proof can only show the absence of attacks in a certain model. What about attacks outside those models?</li> </ul>