Most Useful NFT Knowledge In The Whole Network (3)

In the previous two articles, we introduced the common gameplay and analysis tools of NFT. In this issue, we will introduce the mint method of NFT.

There are three popular mint methods for NFT at present:

1. Front-end mint:
This way of mint is the most common one, and it is also the way most people mint NFT. The specific operation is to use the webpage provided by the project party, connect the wallet and click the mint button to automatically call the smart contract for mint. Because most people are restricted by knowledge of smart contracts and programming, they can only use this mint method to mint NFT. Therefore, the front-end mint is also the mint method adopted by the vast majority of users at present. However, relatively speaking, the front-end mint method has a large user group, and collective mint during a certain period of time is likely to cause block congestion, and the mint speed is slow. If it is a first-come, first-served mint rule, it may cause mint failure. Further Cause gas war and other problems.

2. Contract mint:
Compared with front-end mint, contract mint is a more advanced mint method. The specific operation method is to find the contract address of the project party by opening the blockchain browser, and operate the contract in the read contract and write contract. This method omits the operation of clicking mint on the front end, and the speed is relatively faster.

Next, I will introduce two tools for contract mint:

(1) Tokenview (https://tokenview.com/cn/learn/utxo-api)
Enter the NFT contract address details page through Tokenview, and you can see information such as the number of NFT transactions and active addresses. Change the relevant contract parameters by clicking the write contract, and authorize the wallet to conduct transactions.

(2) Etherscan (https://etherscan.io/)
The same is true for Etherscan. After entering the NFT contract address page, connect to the metamask wallet, select contract, and click the write contract button to send a mint request to the contract by changing the contract parameters. After changing the relevant parameters, the metamask wallet will pop up to confirm the transaction.

3, hexadecimal mint
When it comes to hexadecimal mint, here is an introduction to the fact that the NFT issued by the NBA was madly used by scientists using hexadecimal mint.

In April, the NBA released 18,000 series of The Association NFTs, making 75 NFTs for each of 240 players, and whitelist holders can mint 1 for free. However, because of problems in the mint process of NBA NFTs, some scientists bypassed the official website directly through hexadecimal mint, and even minted a large number of NFTs without a whitelist.

So what is hexadecimal mint? How did the NFT issued by the NBA get ripped off by scientists? Let me introduce to you here.

Hexadecimal (abbreviated as hex or subscript 16) is a hexadecimal base system in mathematics, which converts bits and bytes into hexadecimal numbers for compression. There will be more applications in the field.

Generally speaking, when we use the wallet to interact with the contract, we will pass in certain data for it. These data are usually compressed in the form of hexadecimal. After the contract receives this part of the data, the corresponding identification is performed to define the interface function. And parameters are passed in to form the correct transaction return.

Compared with the contract mint method, the hexadecimal mint actually returns the result through interaction with the contract, and manually generates a transaction input through the ABI of the encode contract.

The hexadecimal mint is operated directly on the metamask wallet side, which is more flexible to a certain extent.

To perform hexadecimal mint, you first need to set metaMask to see hexadecimal data. In Settings — Advanced, turn on “Show Hexadecimal Data”

Then we click the send button during the transaction, and we can see the input box of the hexadecimal input:

So the question is, what should be filled in the hexadecimal input box?

Taking Tokenview as an example, you can first find a successful mint transaction of this series of NFTs on Tokenview, click to view the details, and all the content displayed in the data input section is the content of our method call to the target contract, which should be filled in 16 base content.

Etherscan is the same, find a successful transaction, click to enter the details, you can see the input data, the characters in it are the data converted into hexadecimal when the function interacts with the contract at that time, copy these characters and fill in .

The method is actually very simple to sum up, just find a transaction that has been mint successfully, copy the input of the transaction, then open the little fox wallet, click transfer, enter the NFT contract address, and paste the copied in the hexadecimal data column. input to confirm the transaction.

However, it is unrealistic to skip the whitelist to mint NFTs only by hexadecimal mint. Although the same contract interaction operation can be performed completely, most of the NFT whitelists will be verified by the whitelist during mint.

At present, the more common whitelist verification methods are the methods of on-chain entry and off-chain storage.

On-chain verification is to enter the whitelisted addresses into the blockchain one by one. This method is not only inefficient, but also requires gas payment when entering. If there are a large number of whitelisted addresses, the method of on-chain entry is obviously ineffective. too reasonable.

Off-chain storage means that the project party saves the whitelist address here, and the user will confirm the user’s whitelist identity by verifying the wallet address and signature when mint on the official website.

The NFT issued by the NBA adopts the verification method saved off-chain. However, the mistake of the NFT issued by the NBA is that it did not double-check the address of the whitelist mint with the address of the actual operation. After obtaining the address of the user currently executing the contract (whitelist address), the NFT of mint should have been passed to this whitelist address, but before mint, the address of the link official website (actual operation address) was actually obtained and passed in, which was not carried out. After the second check, users with non-whitelisted addresses succeeded in mint by copying hexadecimal data… This shows how important it is to master the knowledge of contract mint.

Well, through the description of several mint methods, I believe that everyone has a deeper understanding of the mint aspect of NFT. Combined with our previous articles, I hope everyone can find and obtain high-quality NFT projects.

This is the end of the sharing of NFT dry goods articles in these issues. If you are interested, you can also repost and share them~