[Blockchain] understanding of ERC721

[Blockchain] understanding of ERC721

ERC721 defines an indivisible, unique interface specification for token interaction and circulation in Ethereum ecology. The specification is essentially an intelligent contract on the Ethereum, relying on EVM to run. Token (non-fungible Token, NFT) that conform to the specification have the following characteristics: within the scope of the contract, the only token_id token_id can be owned by only one owner (i.e. ETH address) An owner can have more than one nfts, and its balance will only count the quantity. There are other storage list records token_id-owner_addr corresponding relations nft have approve, transfer, takeownership and other interface methods suitable for the function of circulation. That is the ownership transfer. These methods are defined in the ERC721 standard. Defines a multiaddr-type compound address to index the corresponding metadata (name, picture, various information) of the token. Get the token metadata by using the Tokenmetadata method to obtain this multiaddr (a string like a URL). ERC721 and ERC20 's token, there are compatible places, that is, token name, token symbol. It is convenient for ERC20 wallet to show ERC721 token

Currently, the ERC721 use case: the ether cat. Characteristics other than ERC721: fixed time to produce a creation of the cat, two cats can mate, according to the definition of genetic data, genetic algorithms to obtain the characteristics of the offspring of the cat gene. Decentraland. is also a game, through the virtual territory design, construction, create a special territory, and then through the transaction to bring value. ERC721 Features: You can match yourself, feel like creating a "gene" that supports 3D display. Cryptopunks. This is a punk-shaped picture of the trading platform. The platform initially generated a fixed 10,000 punk, each different, and it seems that the feature cannot be changed. Now it's just a trading platform.

For an example explanation of the ERC721 standard, see this article: The Anatomy of ERC721.