Stanford team shines light on cryptocurrency, designs photonic circuits to save energy

Researchers at Stanford University might have a solution. Their answer? A new light-based computing scheme that uses a photonic integrated circuit to reduce the energy necessary for cryptocurrency and blockchain applications.

Cryptocurrencies — digital currencies that require a digital ledger (blockchain) to record transactions and rely on encryption algorithms to maintain their integrity — consume up to one percent of the world’s energy, a cost that will multiply as more of the world embraces crypto, taking it mainstream.

"Currently, cryptocurrency mining is only accessible to those that have access to highly discounted energy— below $0.05/kWh," Sunil Pai, first author of the research at Stanford and now at the quantum computing company PsiQuantum, said in a statement. “Our low-energy chips will make it possible for individuals all over the world to participate in mining profitably.”

The photonic blockchain could impact a ten-ford improvement in energy use

In their paper 'Experimental evaluation of digitally-verifiable photonic computing for blockchain and cryptocurrency', published in Optica, Pai and his peers enumerate on LightHash, their new scheme which uses a photonic integrated circuit to create a photonic blockchain.

"Our approach to photonic blockchain could also be used for applications beyond cryptocurrency such as securely transferring data for medical records, smart contracts, and voting. This work paves the way for low-energy optical computing, which, ultimately, can reduce data centers' energy consumption," Pai added.

The team estimates this photonic blockchain to impact a ten-fold improvement in energy use compared to the best modern digital electronic processors if implemented on a large scale.

Popular cryptocurrencies, including Ethereum, shifted their consensus mechanisms to unproven and potentially insecure strategies to reduce their carbon footprint amidst growing concerns about their energy usage at scale.

LightHash uses silicon photonics to reduce energy requirements while maintaining a high level of security. It is also an improvement on HeavyHash - another scheme developed by the team and currently used by cryptocurrency networks such as Optical Bitcoin and Kaspa.

The team modified HeavyHash to work with a co-designed silicon photonic chip carrying a 6x6 network of programmable interferometers, which facilitates low-energy processing of matrix multiplications that form the bulk of LightHash computation.

“Essentially, we have devised a way to use analog optical circuits to perform multiplications at near zero power dissipation yet precisely enough for use in a digital encryption scheme, ” Pai concluded.

The potential for photonic circuits is not just limited to blockchains and cryptocurrencies. Its ease and energy efficiency in multiplying matrices fashions them into contenders to reform artificial intelligence applications.