Author: Keagan McClelland 2021-05-17 21:13:42
Published on: 2021-05-17T21:13:42+00:00
The Bitcoin network has faced criticism over its energy consumption and environmental impact, which have made it difficult for adoption by companies like Tesla. To address this issue, Michael Dubrovsky and Bogdan Penkovsky proposed "Optical Proof of Work" (oPoW), a low-energy Bitcoin proof of work that decouples mining from energy. The proposal shifts operating expenses to capital expenses, making it feasible for miners in regions with higher electricity costs to participate. This is achieved by using photonic co-processors combined with a small digital core to perform MAC operations.Although oPoW's algorithm is more complicated, it is backward compatible with GPUs, FPGAs, and ASICs. The proposal allows for a transitional period of optical and traditional hardware mining in parallel on the network, making it possible for billions of new miners to enter the market by investing in a low-energy photonic miner. However, Keagan raises concerns about the proposal, stating that it privileges those who have access to chip manufacturers/foundries, creating centralization pressure.The oPoW protocol uses a HeavyHash function that includes Keccak hash, matrix-vector multiplication, and Keccak of the result xorred with the hashed input. The random matrix M coefficients are generated using a pseudo-random number generation algorithm from the previous block header. Photonics accelerators are made by fabricating waveguides in silicon using standard lithography processes. Companies developing optical processors for AI, such as Lightmatter, Lightelligence, Luminous, and Intel, could be compatible with oPoW.The geographic distribution of mining activity relative to the CAPEX/OPEX ratio affects the energy consumption of mining. The mix of energy vs. hardware investment changes from about 50/50 to 10/90 or better, leading to lower energy consumption. The authors recommend considering a change in the block reward schedule currently implemented in Bitcoin as there is no clear way to incentivize miners with transaction fees only.The PoWx team has proposed oPoW as a new type of Proof-of-Work (PoW) that uses optical computing to increase energy efficiency and security. They suggest that oPoW can be used in conjunction with the existing SHA256 Hashcash PoW, potentially allowing for a gradual transition towards oPoW while maintaining security. The team plans to release open-source hardware designs for their oPoW miner prototypes and hopes to demonstrate commercial low-energy mining on their network within the next six months. The paper also suggests that a fixed block reward or slowing the decay of the block reward may be necessary to maintain network security in the long term. The endnotes provide links to related publications and acknowledgments to those who provided feedback on the proposal.
Updated on: 2023-06-14T21:58:36.905451+00:00