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MIT Researchers Create Secure, Fast Anonymity System

The new system, Riffle, uses several existing encryption techniques to provide anonymity for users.

Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory and École Polytechnique Fédérale de Lausanne in Switzerland have developed a new anonymity scheme that provides strengthened security and more efficient bandwidth.

Image: MIT

Anonymity networks are meant to protect people living in oppressive societies. For example, approximately 2.5 million daily users around the world use the Tor network to access the internet anonymously. Recent research from MIT and the Qatar Computing Research Institute, however, revealed weaknesses in Tor’s design that can expose users to adversaries.

The new system, Riffle, promises stronger security. Central to the system is a series of servers called a mixnet, where each server permutes the order in which it received messages before passing them on the next server. That shuffling causes adversaries tracking the point of origin to lose track of the messages by the time they exit the last server.

Riffle, like many anonymity systems, uses a technique known as onion encryption. (“Tor” stands for “the onion router.”) Onion encryption essentially wraps each message in several layers of encryption. Each server in the mixnet removes one layer of encryption to ensure that only the last server knows the message. The system uses a number of other techniques, including verifiable shuffle and authentication encryption.

Moreover, the technique boasts efficiency, taking “only one-tenth as much time as existing systems to transfer a large file between anonymous users,” according to a news release.

The system was devised by Albert Kwon and David Lazar, graduate students in electrical engineering and computer science; Srini Devadas, a professor of electrical engineering and computer science at MIT; and Bryan Ford, an associate professor of computer and communication sciences at the École Polytechnique Fédérale de Lausanne. The team is presenting its findings at the Privacy Enhancing Technologies Symposium in Germany taking place this month.

The full research paper, “Riffle: An Efficient Communication System With Strong Anonymity,” is available on the MIT site.  

About the Author

Sri Ravipati is Web producer for THE Journal and Campus Technology. She can be reached at [email protected].

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