Making blockchain technology more efficient

31 May 2024

In late April, Hong Kong launched its first spot bitcoin and ethereum exchange traded funds. The event marked a milestone in the city’s effort to be the hotspot for the virtual asset sector as Asia’s first city to accept cryptocurrencies as a mainstream investment tool. As the cryptocurrency market continues to grow, so does the use of blockchain technology.

To the uninitiated, cryptocurrency is a digital currency that makes use of blockchain technology, a decentralised network of computers which keep track of transactions. While the application of blockchain technology has potential that extends beyond the realms of the cryptocurrency and financial market, one criticism is its environmental impact.

Blockchains excel in ensuring security, traceability, and transparency, and yet they require a large amount of energy to run. In addition, storing large amounts of data on blockchains can be expensive. It is therefore common practice for blockchains to log a record of transaction across their network as “on-chain” data, and store other data related to that transaction in a database outside the blockchains as “off-chain” data.

“To protect the integrity of off-chain data, cryptographic proof or a digital signature can be constructed online for queries over the stored data. However, existing measures have limitations in the search and retrieval of data,” says Professor Xu Jianliang, Head and Chair Professor of the Department of Computer Science, who specialises in the research on blockchain technology and data security and privacy.

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Professor Xu Jianliang led a research team to develop an innovative solution that can improve gas efficiency and ensure the integrity of queries within a blockchain network. The project recently received a Silver Medal at the 49th Geneva International Exhibition of Inventions.


To address the pressing issues associated with the cost of blockchain data maintenance and the security of off-chain data, Professor Xu and his research team have developed an innovative and economically effective solution.

The project, titled “Gas-efficient Blockchain Technology for Trustworthy Data Storage and Retrieval”, proposes a hybrid on and off-chain storage solution with an authenticated data structure maintained by the blockchain. It also employs a unique model which forecasts the cost of ‘gas’, a unit of computation that measures the work required for actions within blockchains. In the solution developed by the HKBU research team, the gas expenses associated with processing blockchain transactions can be reduced by up to 78%.

“Our solution proposes a blockchain search system that provides a cost-effective way to manage blockchain data by improving gas efficiency and ensuring the integrity of queries within a blockchain network,” says Professor Xu.

He adds that the proposed system guarantees the data obtained through queries remains accurate and unaltered from where it was originally stored. If any information is missing or corrupted, the system can quickly identify and alert users.

The innovative solution recently received a Silver Medal at the 49th Geneva International Exhibition of Inventions. Professor Xu is delighted that the project has been recognised at this international event. He says: “Our research team is committed to pursuing further breakthroughs that can be translated into practical solutions and technologies with the aim of improving people’s quality of life.”

Continuous innovation and improvements will drive the blockchain sector to be more efficient and environmentally sustainable. With far-reaching applications across different industries ranging from healthcare to finance and supply chain, blockchain technology holds a promising future.