Debangsu Sengupta

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This paper proposes a challenge-response authentication system for web applications called Snap2Pass that is easy to use, provides strong security guarantees, and requires no browser extensions. The system uses QR codes which are small two-dimensional pictures that encode digital data. When logging in to a site, the web server sends the PC browser a QR code(More)
This paper presents PrPl, a decentralized infrastructure that lets users participate in online social networking without loss of data ownership. PrPl, short for private-public, has a person-centric architecture--each individual uses a <i>Personal-Cloud Butler</i> service that provides a safe haven for one's personal digital assets and supports sharing with(More)
Advertisement-supported social networking portals generally aim to lock in users' data and exploit personal information for ad targeting and other marketing purposes. Because of the network effect, it is not hard to envision a situation where the information of a very large population can end up in the hands of an oligopolistic group or even a sole(More)
In order to provide multimedia (e.g. image/video) retrieval capabilities, digital libraries have depended on manual annotation of images. Providing a way to perform annotation automatically would be more useful, efficient and scalable with expanding image collections. In this paper, we study the Co-Occurrence Model [2] where, by training on a set of images(More)
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