I generally shy away from super-geeky posts on my blog because it creates the perception that I’m a super geek. On my imaginary geek scale of ho-hum, spirited, super, and uber geek, I rate myself a spirited geek. In this case, it means that I got excited about SSL and have to share!
For my non-geek readers, SSL is the technology that displays itself in the browser address bar as HTTPS, allowing you to feel safe about using your credit card to purchase goods and services online. In the diagram below, notice how the client and the server depend on the Certificate Authority (CA) to verify the interaction.
This dependency is a weakness that Moxie Marlinspike (great name, huh?) talks about in his presentation at Blackhat USA 2011, SSL and The Future of Authenticity. It’s a 48 minute video, so here are some highlights to encourage all geeks to make the time:
- The 2011 hacks of Comodo, one of the world’s largest Certificate Authorities, illustrate the problem. The hacks were much simpler than the CEO of Comodo would have us believe.
- A secure protocol must address three elements: secrecy, integrity and authenticity. SSL handles secrecy and integrity well, but not so much with authenticity. It tries to handle authenticity by having certificates signed by CAs, but the problem is that once the certificate is signed it is trusted forever.
- We are missing “trust agility.” If I no longer trust one CA, I need to be able to revoke that trust and choose another CA. That’s not currently possible.
- Convergence is an agile, distributed and secure solution for replacing CAs. It’s available as a Firefox add-on.
The takeaway here is that while SSL is not a perfect technology, there are uber geeks like Moxie Marlinspike that have viable solutions on the table!