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Math

Improperly Anonymized Logs Reveal Details of NYC Cab Trips 192 192

mpicpp (3454017) writes with news that a dump of fare logs from NYC cabs resulted in trip details being leaked thanks to using an MD5 hash on input data with a very small key space and regular format. From the article: City officials released the data in response to a public records request and specifically obscured the drivers' hack license numbers and medallion numbers. ... Presumably, officials used the hashes to preserve the privacy of individual drivers since the records provide a detailed view of their locations and work performance over an extended period of time.

It turns out there's a significant flaw in the approach. Because both the medallion and hack numbers are structured in predictable patterns, it was trivial to run all possible iterations through the same MD5 algorithm and then compare the output to the data contained in the 20GB file. Software developer Vijay Pandurangan did just that, and in less than two hours he had completely de-anonymized all 173 million entries.
Facebook

The Bursting Social Media Advertising Bubble 254 254

schwit1 writes One of the great "paradigms" of the New Normal tech bubble that supposedly differentiated it from dot com bubble 1.0 was that this time it was different, at least when it came to advertising revenues. The mantra went that unlike traditional web-based banner advertising which has been in secular decline over the past decade, social media ad spending — which the bulk of new tech company stalwarts swear is the source of virtually unlimited upside growth — was far more engaging, and generated far greater returns and better results for those spending billions in ad bucks on the new "social-networked" generation. Sadly, this time was not different after all, and this "paradigm" has also turned out to be one big pipe dream. According to the WSJ, citing Gallup, "62% of the more than 18,000 U.S. consumers it polled said social media had no influence on their buying decisions. Another 30% said it had some influence. U.S. companies spent $5.1 billion on social-media advertising in 2013, but Gallup says "consumers are highly adept at tuning out brand-related Facebook and Twitter content."