How do we secure critical technologies from tampering? The answer may be sending them into orbit

At the IT University of Copenhagen, Associate Professor Bernardo David, is working on a joint research project that aims to send satellites that power cryptographic and blockchain applications into orbit in order to secure them from tampering and to enable time-based primitives based on communication delays.

Bernardo Machado DavidComputer Science DepartmentResearchalgorithmsBlockchaincybercrime

Written January 20, 2022 7:44 AM by Theis Duelund Jensen

Associate Professor at the IT University of Copenhagen, Bernardo David, is currently working on a project that sounds like something out of a sci-fi film, but in reality, has very real-life implications for many of the technological applications we use today. Together with Cryptosat, a company that builds satellites, and the open-source R&D company, Protocol Labs, Bernardo David, and his colleague Carsten Baum from Aarhus University, are working to improve the fundamental conditions for cryptographic and blockchain applications. But how do satellites, blockchain technology, and cryptography fit together?

“Basically, we can conceptualize the project by thinking of a lottery,” says Bernardo David who specializes in cryptography and information theory and is a member of the Center for Information Security and Trust at ITU.

“In a lottery you buy a ticket, and if the sequence of numbers you have selected match the ones picked by the central lottery administration, you win a prize. But what if we do not trust the central lottery administration to pick a winning sequence of numbers at random? The ability to run a lottery without having to rely on a single authority is essential for building energy efficient and scalable blockchains based on the so-called Proof-of-Stake mechanism.”

Decentralized process
By using a distributed lottery mechanism, the need for a central administration is removed and the result is unbiased. However, the blockchain system is still vulnerable to tampering. You may have decentralized the process, but the individual nodes in the network are still corruptible. This is where cryptography comes into play.

“It is also where a satellite network is useful,” says Bernardo David. “It is close to impossible to physically hack satellites, but they can also be applied in other ways.“

They can generate unbiased randomness in a distributed system by using so-called Verifiable Delay Functions, a cryptographic primitive which produces a certain output – in our case a random number – after a given amount of time has lapsed. The fixed delay is necessary in order to make sure that every part of the distributed network receives the random number at the same time. The only problem is that computers compute functions at different speeds depending on their capabilities making the network vulnerable to hackers.

“It is extremely important for security reasons that we can obtain a guaranteed delay on the computation process, but that is very hard, because a powerful computer will be able to compute the delay function faster than a normal computer. In our project, instead of building on computation, we turn to physics,” says Bernardo David.

Sending signals from orbit
Electromagnetic signals travel at the speed of light which means that by relaying an electromagnetic signal between nodes, it is possible to implement a universal delay function. As the signal on Earth would have to travel between nodes several thousand times before reaching a delay of only one minute, this process is done much more efficiently if the nodes are satellites orbiting the planet. The bigger the sphere, the fewer relays a signal has to make.

The technology is not only applicable to our lottery scenario. As Bernardo David explains, many technologies in different sectors rely on randomized input and it is of the utmost importance to secure the process:

“Time-based primitives have the potential to improve the security, privacy, and scalability of blockchain platforms and other cryptographic protocols. With this technology we hope to guarantee trust and transparency in everything from blockchain to Internet transactions.”

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