This standard extends ERC-721 by binding individuals’ Web2 and Web3 identities to non-fungible tokens (SBTs included). By binding multiple identities, aggregated and composible identity infomation can be verified, resulting in more beneficial onchain scenarios for individuals, such as self-authentication, social overlapping, commercial value generation from user targetting, etc. By adding a custom schema in the metadata, and updating and verifying the schema hash in the contract, the binding of NFT and identity information is completed.