All posts by Soren Preibusch

Privacy economics: evidence from the field

It has been argued that privacy is the new currency on the Web. Services offered for free are actually paid for using personal information, which is then turned into money (e.g., using targeted advertising). But what is the exchange rate for privacy? In the largest experiment ever and the first done in field, we shed new light on consumers’ willingness to pay for added privacy.

One in three Web shoppers pay half a euro extra for keeping their mobile phone number private. If privacy comes for free, more than 80% of consumers choose the company that collects less personal information, our study concludes.

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Passwords in the wild, part III: password standards for the Web

This is the third part in a series on password implementations at real websites, based on my paper at WEIS 2010 with Joseph Bonneau.

In our analysis of 150 password deployments online, we observed a surprising diversity of implementation choices. Whilst sites can be ranked by the overall security of their password scheme, there is a vast middle group in which sites make seemingly incongruous security decisions. We also found almost no evidence of commonality in implementations. Examining the details of Web forms (variable names, etc.) and the format of automated emails, we found little evidence that sites are re-using a common code base. This lack of consistency in technical choices suggests that standards and guidelines could improve security.

Numerous RFCs concern themselves with one-time passwords and other relatively sophisticated authentication protocols. Yet, traditional password-based authentication remains the most prevalent authentication protocol on the Internet, as the International Telecommunication Union–itself a United Nations specialized agency to standardise telecommunications on a worldwide basis–observes in their ITU-T Recommendation X.1151, “Guideline on secure password-based, authentication protocol with key exchange.” Client PKI has not seen wide-spread adoption and tokens or smart-cards are prohibitively cost-inefficient or inconvenient for most websites. While passwords have many shortcomings, it is essential deploy them as carefully and securely as possible. Formal standards and guidelines of best practices are essential to help developers.

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