I've spent nearly ten years of my life building something that's too big.

I've done a lot of thinking about this — more than you would probably guess. It's occupied a large part of my technical thinking for the past four or five years, and has helped shaped everything I've written in that time, both in blogs and in code.

For the rest of this little rant, I'm going to assume that you're a young, intelligent, college age or even high school age student interested in becoming a better programmer, perhaps even a great programmer.

Code's Worst Enemy

Andy Oram:

A common lament is that the early Internet was invented without a view toward security, much less reputation. Considering that the first intended use of the Internet was a kind of 1970’s-style grid computing (time-sharing on supercomputers), the inventors should have had both security and reputation in mind. Nowadays we need reputation even more.

Reputation: where the personal and the participatory meet up

At last. Realtime outlining for the web.

Collaborate in realtime using a structured and flexible outline format.

Create ideas, make notes, build plans, share files, agree tasks and organise everything in a single shared workspace, using just your web browser.

ThinkFold: Realtime outlining for groups

Luminotes is a WYSIWYG personal wiki notebook for organizing your notes and ideas. It's designed for creating highly interconnected documents with many links between concepts. Streamlined visual editing allows you to create your wiki without having to use any special markup codes or switch to a separate edit mode.

Most wikis are designed for creating one large document per page. But for your own notes, this approach can grow rather unwieldy. With Luminotes, you deal with several notes all at once on the same web page, so you get a big-picture view of what you're working on and can easily make links from one concept to another.

Luminotes is open source / free software and licensed under the terms of the GNU GPL.

Luminotes: personal wiki notebook

The spread of wide-scale Internet surveillance has spurred interest in anonymity systems that protect users’ privacy by restricting unauthorised access to their identity. This requirement can be considered as a flow control policy in the well established field of multilevel secure systems. I apply previous research on covert channels (unintended means to communicate in violation of a security policy) to analyse several anonymity systems in an innovative way.

One application for anonymity systems is to prevent collusion in competitions. I show how covert channels may be exploited to violate these protections and construct defences against such attacks, drawing from previous covert channel research and collusion-resistant voting systems.

In the military context, for which multilevel secure systems were designed, covert channels are increasingly eliminated by physical separation of interconnected single-role computers. Prior work on the remaining network covert channels has been solely based on protocol specifications. I examine some protocol implementations and show how the use of several covert channels can be detected and how channels can be modified to resist detection.

I show how side channels (unintended information leakage) in anonymity networks may reveal the behaviour of users. While drawing on previous research on traffic analysis and covert channels, I avoid the traditional assumption of an omnipotent adversary. Rather, these attacks are feasible for an attacker with limited access to the network. The effectiveness of these techniques is demonstrated by experiments on a deployed anonymity network, Tor.

Finally, I introduce novel covert and side channels which exploit thermal effects. Changes in temperature can be remotely induced through CPU load and measured by their effects on crystal clock skew. Experiments show this to be an effective attack against Tor. This side channel may also be usable for geolocation and, as a covert channel, can cross supposedly infallible air-gap security boundaries.

This thesis demonstrates how theoretical models and generic methodologies relating to covert channels may be applied to find practical solutions to problems in real-world anonymity systems. These findings confirm the existing hypothesis that covert channel analysis, vulnerabilities and defences developed for multilevel secure systems apply equally well to anonymity systems.

Covert channel vulnerabilities in anonymity systems

In response to Josh Catone’s observation that del.icio.us has failed to go mainstream, Richard Ziade offers three hypotheses:

1. Nobody really needs a way to centrally store their bookmarks
2. Most people don’t understand what del.icio.us does
3. People don’t feel compelled to share del.icio.us with others

The winning explanation, I am sure, is #2. Nobody understands what del.icio.us does. I am constantly explaining the nature and value of its social information management capabilities. Just this week, in various meetings on Microsoft’s Redmond campus, I found myself reiterating four of my major uses of del.icio.us.

Jon Udell: Discovering versus teaching principles of social information management

The Situated Technologies Pamphlet series explores the implications of ubiquitous computing for architecture and urbanism: How is our experience of the city and the choices we make in it affected by mobile communications, pervasive media, ambient informatics, and other “situated” technologies? How will the ability to design increasingly responsive environments alter the way architects conceive of space? What do architects need to know about urban computing and what do technologists need to know about cities? Situated Technologies Pamphlets will be published in nine issues and will be edited by a rotating list of leading researchers and practitioners from architecture, art, philosophy of technology, comparative media study, performance studies, and engineering.

Download it for free.

Urban Computing and its Discontents

A short video explaining OpenID

OpenID According to Dave

Equipping law-enforcement services with Tasers is likely to reduce the number of bullets officers fire from their handguns and therefore the number of serious injuries and deaths. At the same time, it may lead police to inflict an unwarranted amount of pain on individuals who commit only minor crimes.

The broader questions regarding the social effects of stun guns are, however, beyond the scope of this discussion. The two articles that follow investigate the physiological effects of electric shock. The first is by Mark W. Kroll, an electrical engineer who has helped invent numerous electrical medical devices and who sits on the board of Taser International. The second is by Patrick Tchou, a cardiac electrophysiologist at the Cleveland Clinic, who has tested Tasers experimentally on pigs.

IEEE Spectrum: How a Taser Works

Tagging communities are popular instances of a broad class of online communities based on user-generated content. In these communities users introduce and tag content for later use. Although recent studies advocate and attempt to harness social knowledge generated in this context, little research has been done to quantify the current level of user collaboration in these communities. This paper introduces two metrics to quantify the level of collaboration: content reuse and shared interest. Using these two metrics, this paper shows that the current level of collaboration in CiteULike and Connotea is consistently low, which significantly limits the potential of harnessing the social knowledge in collaborative communities. This study also discusses implications of these findings in the context of recommendation and reputation systems.

Content Reuse and Interest Sharing in Tagging Communities