Institute Fellow Sharon Goldberg Designs Anonymous Bitcoin Payment System

As the surveillance industry continues to expose weaknesses in Bitcoin’s security properties, one of most valuable attributes of the system, payment anonymity, has come into question. Led by Hariri Institute Faculty Fellow and computer science professor Sharon Goldberg, a team of BU researchers, including PhD candidate Ethan Heilman, undergraduate student Leen Alshenibr, and postdoc researchers Foteini Baldimtsi and Allesandra Saguaro, designed TumbleBit, a new Bitcoin-compatible unlinkable payment hub. Their work further establishes BU’s leadership role in developing cutting-edge research that’s shaping the future of cyber security.

TumbleBit provides a platform through which parties can make fast, anonymous, off-blockchain payments through an untrusted intermediary called the Tumbler. However, no party, including the Tumbler, can link a payment from payer to payee. This creates a powerful tool that makes up for the demonstrated weaknesses in Bitcoin’s anonymity properties. As researchers note, “if the service knows exactly which payer is paying which payee, then a compromise of the service leads to a total loss of anonymity.” The platform uses cryptographic techniques to ensure the intermediary can’t violate anonymity, steal bitcoins, or “print money” by issuing payments to itself. Furthermore, because TumbleBit payments take place off of the Bitcoin blockchain, the platform can process a payment 1.2 seconds as compared to the 10 minute process time for bitcoin transactions made on the blockchain.

The paper, released Friday, August 26, has already gained significant buzz in the bitcoin world. A recent reddit thread about the paper has generated a lively discussion of the platform’s unique properties and Ansel Lidner spoke about Tumblebit during a segment in “Bitcoin and Markets” podcast segment. The BitcoinBlog.de also praises the researchers’ work.

[read the paper or view the GitHub repository]