Computer scientists build a faster, secure, energy-efficient blockchain system

Blockchain technology was unveiled nearly 35 years ago, but it first became prominent more recently—in 2009, with the introduction of Bitcoin—giving this “digital ledger” an everyday, consumer purpose. However, while blockchains have been used for payments, digital contracts, and supply chains, blockchain systems still achieve a low transaction rate with high energy and transaction costs.

A team of New York University computer scientists has now developed an alternative approach to blockchain design, Bounce, that relies on satellites to determine the order of the blocks, where each block is a set of transactions. In the Bounce protocol, encodings of many blocks reach the satellite responsible for a time slot and that satellite orders these blocks and “bounces” them back. 

“The benefit of satellites is that they are hard to access, are secure against side-channel attacks, and their processing can be made tamper-resistant,” says Dennis Shasha, a professor of computer science at New York University’s Courant Institute of Mathematical Sciences and the senior author of the research, which appears in the journal MDPI Network. “The Bounce protocol on the satellite computers is so simple, it can be burned into read-only memory, thus preventing software-injection attacks.”

“While real-world deployment may present some practical challenges,” adds Shasha, associate director of NYU Wireless, “Bounce provides a foundation for future research and development of high-performance, energy-efficient, globally accessible blockchain systems.” 

Bounce processes more than five million transactions every two seconds with transaction confirmation response time of between three and 10 seconds. Its throughput is thus 30 to 100 times greater than that of its nearest competitor, Solana, which is a state-of-the-art system that is known for its speed. 

The energy cost of Bounce is less than 1/10th of a joule per transaction. By contrast, Solana has an energy consumption of over 1,000 joules per transaction—one joule fuels one watt per second. Bitcoin, which achieves fewer than 100 transactions per second, has an energy consumption well over one million joules per transaction.

The Bounce blockchain protocol calls for a set of satellites that partition time slots—blockchain’s basic time units. Because the satellite for each slot orders the blocks it receives during that slot, the Bounce system completely avoids “forks.” A “fork” occurs when a blockchain splits into two or more separate chains, making it possible, for example, to buy different items with the same funds—an attack known as “double-spending.” 

The researchers conducted experiments to confirm the efficacy of the model using CloudLab, which is backed by the National Science Foundation’s Cloud Access program (1840761 A002). CloudLab allows researchers to build their own clouds in order to build and test the next generation of computing platforms. The earth-to-satellite communication times were done with the International Space Station.

The paper’s other authors were Xiaoteng Liu, an NYU undergraduate, and Taegyun Kim, an NYU graduate student at the time the first prototype was built and now a software engineer at Datadog. 

The study was supported by NYU Wireless, an academic research center at NYU’s Tandon School of Engineering that backs advances in wireless communications, sensing, networking, and devices.

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