We often see the ERC standard in many tokens, including USDT, which we use most often. Many times we use the ERC standard. So what is the ERC standard?

Before talking about ERC, we need to understand that smart contracts are actually a set of promises defined by the digital situation. The immutability advantage of smart contracts makes them naturally applicable to the contract terms scenario, effectively reducing malicious tampering and human intervention. For example, a bank-like smart contract could be written on Ethereum, through which people could access money. In this way, there will be no misalignment of balances due to errors or malicious changes by bank staff.

The Ethereum smart contract allows contract developers to develop new projects and issue their own tokens, but it has to follow a prescribed procedure. It has its own set of standards to effectively prevent all kinds of messy tokens, data, and so on from emerging on the platform. This standard is the ERC we are going to talk about today.

What is the ERC?

The full name of ERC is "Ethereum Request for Comment", which means the protocol proposal submitted by Ethereum developers. ERC contains technical and organizational considerations and standards, and the number after ERC is the number of the proposal. The most common ERC standards are ERC-20 and ERC-721.

The ERC-20 is the most widely known standard. It was created in 2015 and officially standardized in September 2017. The protocol specifies a set of basic interfaces for fungible tokens, including token symbols, issuance, transfers, authorizations, etc. In the ERC-20 standard there is no value distinction, tokens are interchangeable. That is, under the ERC-20 standard, any unit of currency has the same value. The ERC-20 standard specifies that a Token needs to have its name, symbol, total supply, and other functions including money transfer and remittance. The benefit of this standard is that as long as the Token is ERC-20 compliant, it will be compatible with the Ethereum wallet. In other words, you can add the Token to your Ethereum wallet and send it to others through your wallet. Because of the ERC-20 standard, it is easy to issue tokens. Currently, the number of ERC-20 tokens on Ethereum exceeds 180,000.

The ERC-721 standard specifies that a Token that meets the standard must have a unique Token ID. In ERC-721, each Token is unique. Take the blockchain game infatuation cat as an example, each cat is endowed with a gene, which is unique and cannot be replaced at will. This uniqueness makes some rare cats have collection value and are sought after by the public, which is one of the reasons why NFT is popular at present.

Erc-20 and ERC-721 are both standard protocols for Ethereum Token issuance. However, the tokens issued based on ERC-20 standard have no value difference, are interchangeable and can be split. The tokens issued based on ERC-721 are not interchangeable, each Token is unique and cannot be split.

Some other ERC standards

Erc-809: NFT available for hire

The ERC-809 standard is a rentable NFTS standard that creates an API that allows users to rent any "rentable" NFTS. In short, it adds rental capabilities to the ERC-721 protocol. Unlike other standards, ERC-809 is exclusive in that when one person leases an NFT, no other user can access or use the NFT.

Erc-875: Batch transferable NFTS

In the ERC-875 protocol, users are allowed to bulk transfer or trade multiple NFTS in a single transaction, and the transfer or transaction fee is cheaper. In the ERC-875 protocol, users are able to place orders by signing encrypted signatures containing information such as price, expiration date and signature. This process is done off-chain and is only broadcast on-chain when settlement is made, which means users can make transactions without paying Gas fees. When a buyer is willing to buy, all he needs to do is accept the order and broadcast it with the order details, plus buy the gold to complete the transaction.

Erc-998: detachable ERC-721

The ERC-998 is a Composable NFT, or CNFT. It is designed so that any NFTS can own other NFTS or FTS. When you move a CNFT, you move the entire hierarchy and ownership of the CNFT. Simply put, an ERC-998 item can contain multiple ERC-721 and ERC-20 items.

Erc-1155: NFTS more suited to blockchain gaming

Erc-1155 can define multiple items (tokens) in a smart contract. Erc-1155 can also be used to combine multiple items (tokens) and package them into a single item (Token package). The ERC-1155 incorporates some of the advantages of the ERC-20 and ERC-721, allowing developers to easily create a large variety of items, each of which can be as individual as the ERC-721 or as homogeneous as the ERC-20.

IP-1523: Insurance agreement for NFT

Insurance policies are an important class of financial assets, and it is natural to represent these assets as a class of irreplaceable tokens that follow the established EIP-721 standard. Therefore, we propose a standard for the incidental metadata structure needed to uniquely define an insurance policy.

Erc-1948: NFTS that store dynamic data

Erc-1948 protocol is based on ERC-721, adding a 32 byte data field to the NFT, and allows the user to access the NFT's read function, and the owner of the NFT also has the permission to update the data.

Eip-2981: Ethereum protocol focused on NFT royalties

Eip-2981 allows Digital assets to offer simple, standardized and GAS efficient solutions to any third party, knowing what contract royalties are expected to be paid. Essentially, the EIP-2981 protocol focuses on simplicity and is designed to help the wider adoption of NFTS. In the EIP-2981 protocol, developers provide a variety of royalty collection methods for current NFT transactions. For example, a fixed royalty: 12.5% of sales are sent to the original author; Dynamic Royalty: Royalty rates vary depending on the time of sale or sales. Stepwise royalties: No royalties are generated when the sale price is less than $100.

In addition to the specification of Token contracts, other ERC standards, including but not limited to packet design, interface definition rules and so on, also have some ERC standards. These standard protocols were proposed by the Ethereum team and enthusiasts and contributors.