What is BeamHash?

BeamHash is a modified variant of the Equihash family of Proof of Work algorithms, specifically evolved through three iterations — BeamHash I, II, and III — with BeamHash III being the current production version used by the Beam blockchain. Like its Equihash ancestor, BeamHash is based on the Generalized Birthday Problem, requiring miners to find collisions in a set of hash values under specific constraints. However, BeamHash III introduces modifications to the original Equihash parameters and adds extra computational steps that make it significantly harder to develop efficient ASIC miners while remaining well-suited for GPU mining.

The key design goal of BeamHash is to maintain strong ASIC resistance while providing fair and efficient GPU mining. BeamHash III achieves this through memory-hard properties that require substantial amounts of fast memory during computation, making the cost of ASIC development prohibitively high relative to the advantage it would provide over GPUs. The algorithm also features a verification process that is much faster than the mining process itself, allowing nodes to quickly validate blocks without needing specialized hardware. Each iteration of BeamHash was introduced as a planned hard fork to stay ahead of potential ASIC development, demonstrating a proactive approach to maintaining mining decentralization.

BeamHash is used exclusively by Beam, a privacy-focused cryptocurrency built on the MimbleWimble protocol. Beam launched in January 2019 and has undergone scheduled hard forks to upgrade its mining algorithm from BeamHash I to BeamHash II and finally to BeamHash III, which was activated in June 2020. The MimbleWimble protocol provides Beam with strong privacy features including confidential transactions and no permanent addresses, while BeamHash ensures that block production remains accessible to consumer-grade GPU hardware. This combination of privacy technology and democratic mining has positioned Beam as a notable project in the privacy coin space.