Minting Non-Fungible Tokens with Provably Fair Procedural Generation

Implementing provable fairness in the minting process of non-fungible tokens (NFTs) enables the procedural generation of NFT metadata that can be verified in a decentralized manner, even when stored off-chain. Until now, smart contracts have required additional on-chain data, such as integrity digests, to support the verification of off-chain NFT metadata. Due to the high costs of on-chain data storage, most NFTs do not implement such validation methods, reducing trust in the NFT's off-chain metadata and increasing reliance on centralization. We propose a new method, inspired by the virtual ecology design of sandbox massively multiplayer online role-playing games (MMORPGs). This method utilizes a 256-bit unsigned integer representing a seed value, a Web3-compatible implementation of a pseudorandom number generator (W3PRNG), and an executable ruleset containing attribute definitions and their probability spaces to procedurally generate NFTs. This methodology provides users with a provably fair way of generating NFTs in an open-ended minting smart contract by imitating Proof-of-Work mining, including an arbitrary amount of work to be performed while initializing the PRNG. Due to the extremely large state space of 2^256 possible seeds, any implementation makes the NFT's economy inherently inflationary, offering more attractive features and higher utility in Web3 and Metaverse design than existing fixed supply NFT collections. Furthermore, such a system implicitly guarantees the veracity of off-chain metadata based on the on-chain seed value and the smart contract's immutable integrity configuration. (First published to the Future of Gaming Discord community in November, 2022)