Author: Arvind Narayanan
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Sign up now for the Bitcoin and cryptocurrency technologies online course
At Princeton I taught a course on Bitcoin and cryptocurrency technologies during the semester that just ended. Joe Bonneau unofficially co-taught it with me. Based on student feedback and what we accomplished in the course, it was extremely successful. Next week I’ll post videos of all the final project presentations. The course was based on…
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Consensus in Bitcoin: One system, many models
At a technical level, the Bitcoin protocol is a clever solution to the consensus problem in computer science. The idea of consensus is very general — a number of participants together execute a computation to come to agreement about the state of the world, or a subset of it that they’re interested in. Because of…
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It’s time to bring Bitcoin and cryptocurrencies into the computer science curriculum
In the privacy technologies grad seminar that I taught last semester, Bitcoin proved to be the most popular topic among students. Two groups did very different and equally interesting final projects on Bitcoin and cryptocurrencies; more on that below. More broadly, we’re seeing a huge demand for learning the computer science underlying Bitcoin, both at…
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No silver bullet: De-identification still doesn't work
Paul Ohm’s 2009 article Broken Promises of Privacy spurred a debate in legal and policy circles on the appropriate response to computer science research on re-identification techniques. In this debate, the empirical research has often been misunderstood or misrepresented. A new report by Ann Cavoukian and Daniel Castro is full of such inaccuracies, despite its claims of “setting…
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Encryption as protest
As a computer scientist who studies Privacy-Enhancing Technologies, I remember my surprise when I first learned that some groups of people view and use them very differently than I’m used to. In computer science, PETs are used for protecting anonymity or confidentiality, often via application of cryptography, and are intended to be bullet-proof against an…
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Why King George III Can Encrypt
[This is a guest post by Wenley Tong, Sebastian Gold, Samuel Gichohi, Mihai Roman, and Jonathan Frankle, undergraduates in the Privacy Technologies seminar that I offered for the second time in Spring 2014. They did an excellent class project on the usability of email encryption.] PGP and similar email encryption standards have existed since the early…
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The importance of anonymous cryptocurrencies
Recently I was part of a collaboration on Mixcoin, a set of proposals for improving Bitcoin’s anonymity. A natural question to ask is: why do this research? Before I address that, an even more basic question is whether or not Bitcoin is already anonymous. You may have seen back-and-forth arguments on this question. So which…
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Eternal vigilance is a solvable technology problem: A proposal for streamlined privacy alerts
Consider three recent news articles about online privacy: Google+ added a new feature that shows view counts on everything you post, including your photos. It’s enabled by default, but if you don’t want to be part of the popularity contest, there’s a setting to turn it off. There is a new privacy tool called XPrivacy…
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Bitcoin hacks and thefts: The underlying reason
Emin Gün Sirer has a fascinating post about how the use of NoSQL caused technical failures that led to the demise of Bitcoin exchanges Flexcoin and Poloniex. But these are only the latest in a long line of hacks of exchanges, other services, and individuals; a wide variety of bugs have been implicated. This suggests…