A new type of proof-of-work based on searching for prime numbers is introduced in peer-to-peer cryptocurrency designs. Three types of prime chains known as Cunningham chain of first kind, Cunningham chain of second kind and bi-twin chain are qualified as proof-of-work. Prime chain is linked to block hash to preserve the security property of Nakamoto’s Bitcoin, while a continuous difficulty evaluation scheme is designed to allow prime chain to act as adjustable-difficulty proof-of-work in a Bitcoin like cryptocurrency.
Introduction
Since the creation of Bitcoin [Nakamoto 2008], hashcash [Back 2002] type of proof-ofwork has been the only type of proof-of-work design for peer-to-peer cryptocurrency.
Bitcoin’s proof-of-work is a hashcash type based on SHA-256 hash function. In 2011, ArtForz implemented scrypt hash function for cryptocurrency Tenebrix. Even though there have been some design attempts at different types of proof-of-work involving popular distributed computing workloads and other scientific computations, so far it remains elusive for a different proof-of-work system to provide minting and security for cryptocurrency networks.
In March 2013, I realized that searching for prime chains could potentially be such an alternative proof-of-work system. With some effort a pure prime number based proof-ofwork has been designed, providing both minting and security for cryptocurrency networks similar to hashcash type of proof-of-work. The project is named primecoin.
primecoin whitepaper