27.05.2022

Sustainable Blockchain

What would you do with €1,882,244? – A sustainable blockchain? Results from five years of European-funded cryptography research at ISTA. For many, this question remains a mere pipe dream, but in the case of Krzysztof Pietrzak, Professor of Computer Science specializing in cryptography at the Institute of Science and Technology Austria (ISTA), the proposed answer was convincing enough to secure the funding in the form of a grant from the European Research Council (ERC). With the money he received in 2015, he set about mathematically proving the security of existing algorithms, thereby expanding the foundations of cryptography. “We made progress on all the projects in this application, but the most exciting research, such as that on sustainable blockchains, arose spontaneously,” says Pietrzak. “Especially for us theorists, the outcome of ERC funding can be quite different from what we expect.”

STOCKFOTO*

Curiosity and Successfully Securing EU Funding

Curiosity-driven research at ISTA has proven highly successful in securing the highly competitive ERC grants: 43 professors have already received 52 such grants, totaling €86.5 million. The ISTA Grant Office offers top researchers additional support with the application process. This European Union funding program enables excellent basic research in all disciplines and, in Pietrzak's case, has funded internships, doctoral positions, and postdoctoral research. They worked on alternative cryptocurrencies and the theoretical foundations of the field.

Pietrzak*

Proof of Space

Bitcoin and other cryptocurrencies operate using blockchains based on the "Proof of Work" principle. Blocks are essentially public lists of transactions that are then linked together to form a chain—the blockchain. The blockchain contains the entire transaction history and cannot be altered. To prevent potential attackers, adding blocks to the chain is computationally very expensive. For honest participants, rewards in the form of cryptocurrency "coins" are the incentive to contribute computing power and calculate the next block. Abuse of the system is prevented by making it virtually impossible for any single individual to control more computing power than all honest participants combined. Despite its success, Pietrzak and his colleagues identified significant flaws as early as 2011.

Can a blockchain be democratic and environmentally friendly?

Specialized hardware allows for much more efficient block searching than general-purpose processors like CPUs. This specialized hardware is currently being used by large players, thus undermining the decentralized, democratic principle that everyone can contribute with their own CPU: meaning smaller players have fewer opportunities!

Furthermore, the calculations consume energy, and depending on the hardware's location, this energy is generated from fossil fuels, causing CO2 emissions. With current CO2 emissions of 75 million tons per year, Bitcoin alone has almost the same carbon footprint as Austria, exacerbating the climate crisis. "And for the protocol to function, honest parties have to constantly consume more energy than dishonest ones to maintain the Bitcoin system," Pietrzak criticizes the wasteful concept.

Krzysztof and his friends find the space

Krzysztof Pietrzak and his colleagues have proposed an alternative proof-of-space system. It is not based on constant computation, but on free storage space. A "Proof of Space" uses free disk space, not computations, to secure the blockchain. The storage space only needs to be initialized once; after that, searching for blocks is virtually resource-neutral, resulting in a much more efficient cryptocurrency.

What else is being researched in the field of computer science?

For example, research is being conducted on verifiably delay functions. What are they? These are functions whose computation is inherently sequential and therefore cannot be accelerated by parallel computations. Recently, they have found applications in digital timestamps and replication proofs.

What else? For example, memory-hard functions. Such functions are necessary to prevent attacks that try passwords repeatedly until they find the correct one.

In the future, the group plans to continue its cutting-edge research in the area of sustainable cryptocurrencies, focus on secure group messaging, and refine leak-resistant encryption. The latter refers to cryptographic methods that remain secure even if the underlying hardware is tampered with.

Alles in allem: spannend und ein bisschen geheimnisvoll!