hanno

Since a few months we have a new version of TLS, the most important encryption protocol on the Internet. From the vulnerabilities that created the need of a new TLS version to the challenges of deploying it due to broken devices this talk will give an overview of the new TLS 1.3.

In August the new version 1.3 of the Transport Layer Security (TLS) protocol was released. It‘s the result of a process that started over four years ago when it became increasingly clear that previous TLS versions suffered from some major weaknesses. In many ways TLS 1.3 is the biggest step ever done in the history of TLS and its predecessor SSL. While previous TLS versions always tried to retain compatibility and not change too many things, the new version radically removes problematic and insecure constructions like static RSA key exchanges, fragile CBC/HMAC constructions and broken hash functions like MD5 and SHA1. As a bonus TLS 1.3 comes with a reworked handshake that reduces the number of round-trips and thus provides not just more security, but also better performance. If that sounds too good to be true: An optional, even faster mode of TLS 1.3 – the zero round trip or 0RTT mode – makes some security researchers worried, because they fear it introduces new security risks due to replay attacks. Though the road to TLS 1.3 was complicated. The Internet is a buggy place and particularly Enterprise devices of all kinds – middleboxes, TLS-terminating servers and TLS-interception devices – slowed down the deployment and finalization of the new encryption protocol. Also some banks thought that TLS 1.3 is too secure for them. The talk will give an overview of the developments that led to TLS 1.3, the major changes it brings, the challenges it had to face and some practical advice for deployment.

We're supposed to trust evidence-based information in all areas of life. However disconcerting news from several areas of science must make us ask how much we can trust scientific evidence.

The field of psychology is faced with a crisis where many results that were trusted for decades are called into question. Obviously bogus results like one trying to prove that precognition is real can be created with the existing scientific standards. In replication attempts in preclinical cancer research more than 90 percent of study results could not be confirmed. Pharmaceutical companies are constantly under attack for questionable research methods. The scientist John Ioannidis asked more than ten years ago "Why most scientific research findings are false". These aren't just single incidents, they show much deeper problems in the way science is performed today. Scientific results get published if they yield to "positive" results and land in the drawer if the results are "negative", giving an incomplete and often skewed picture. In many fields scientific studies are never replicated. Scientific incentive structures like the Impact Factor prefer sensational results more than rigorous scientific standards. But there's also some move into the right direction. Trials registers or registered reports can prevent or at least detect many questionable research practices. The replication crisis has led some fields to put more emphasis on repetitions of important results. Appart from the fact that we get a wrong picture of reality these shortcomings of science also are undeserved munition for those who'd like to reject the scientific principle as a whole. How broken is science - and what can be done to make more scientific results true?

Applied IT security is largely a science-free field. The IT-Security industry is selling a range of products with often very questionable and sometimes outright ridiculous claims. Yet it's widely accepted practice among users and companies that protection with security appliances, antivirus products and firewalls is a necessity. There are no rigorous scientific studies that try to evaluate the effectiveness of most security products or strategies. Evidence-based IT security could provide a way out of the security nihilism that's often dominating the debate – however it doesn't exist yet.

From Next-Generation APT-Defense to Machine Learning and Artificial Intelligence: The promises of IT security product vendors are often bold. Some marketing promises are simply impossible, because they violate a fundamental theorem of computer science, the halting problem. Many IT security professionals are skeptical of security appliances, antivirus software and other IT security products and call them snake oil. Furthermore security products often have security vulnerabilities themselves, which has lately been shown by the impressive work done by Tavis Ormandy from Google's Project Zero. When there's disagreement about the effectiveness of an approach then rational people should ask for scientific evidence. However, surprisingly this evidence largely doesn't exist. While there obviously is a lot of scientific research in IT security it rarely tries to answer practical questions most relevant to users. Decisions are made in an ad-hoc way and are usually based on opinions rather than rigorous scientific evidence. It is quite ironic that given the medical analogies this field likes to use (viruses, infections etc.), nobody is looking how medicine solves these problems. The gold standard of scientific evidence in medicine (and many other fields) is to do randomized controlled trials (RCTs) and meta-analyses of those trials. An RCT divides patients in groups and a treatment – for example a new drug – is compared against a placebo treatment or against the current best practice. Single trials are usually not considered sufficient, therefore meta-analyses pool together the results of all trials done on a particular question. There's no reason RCTs couldn't be applied to the question whether a particular security product works. Evidence-based medicine is undoubtedly the right approach, but these methods aren't without problems. Publication Bias skews results, many studies cannot be replicated and the scientific publishing and career system is often supporting poor scientific practices. But this doesn't question the scientific approach itself, it just means that more rigorous scientific practices need to be implemented. Unfortunately, in the few cases where controlled studies are done in the Infosec world they often suffer from the most basic methodological problems like being underpowered (too few participants), never being independently replicated or not measuring relevant outcomes. (There are a few studies on password security and similar questions.) Applying rigorous science to IT security could provide a way out of the security nihilism that dominates the debate so often these days - “Everything is broken, everyone's going to get hacked eventually”. And by learning from other fields Evidence-Based IT Security could skip the flaws that rife other fields of science.