Ethereum ERC-721 standard – NFT

Ethereum ERC-721 is a standard for Non-Fungible Tokens (NFTs) on the Ethereum blockchain. It defines a set of rules and requirements for creating and managing unique digital assets that can be owned, traded, and transferred just like physical assets.

The ERC-721 standard defines a specific set of smart contract functions that must be implemented in order for a token to be considered an ERC-721 token. These functions include:

  • balanceOf(address _owner): Returns the number of ERC-721 tokens owned by a specific address.
  • ownerOf(uint256 _tokenId): Returns the address that owns a specific ERC-721 token.
  • transfer(address _to, uint256 _tokenId): Transfers ownership of a specific ERC-721 token from one address to another.
  • approve(address _approved, uint256 _tokenId): Allows one address to transfer ownership of a specific ERC-721 token on behalf of another address.

These functions are used to handle the unique ownership and transfer of NFTs. They can be used to mint new NFTs, check the ownership of NFTs, and transfer the ownership of NFTs between addresses.

An example of a project that uses ERC-721 standard is CryptoKitties, which is a game that allows players to purchase, breed, and trade virtual cats. In CryptoKitties, each cat is represented by a unique ERC-721 token on the Ethereum blockchain. Players can use the ERC-721 smart contract functions to purchase and own a specific cat, and to transfer ownership of the cat to another player.

In summary, Ethereum ERC-721 is a standard for creating and managing Non-Fungible Tokens (NFTs) on the Ethereum blockchain. It defines a set of smart contract functions that must be implemented to handle the unique ownership and transfer of NFTs, and it enables the creation of unique digital assets that can be owned, traded, and transferred just like physical assets.