Discussion on NFT Technology

2021 year 3 month , By social media “ twitter ”(Twitter) cofounder 、 CEO Jack · Dorsey (Jack Dorsey) The first tweet sent out （ The figure below ）, With nonhomogeneous tokens (NFT) In the form of auction , In the end, it surpasses 290 Ten thousand dollars for sale .

2021 year 6 month , A picture in pixel art style 《CryptoPunk 7523》NFT Head portrait （ The figure below ）, At Sotheby's auction house in New York 1175 It's a million dollars deal .

More and more companies are pouring into NFT On the track , part NFT The transaction price of digital goods is unimaginable , It's worth it , Or hot money speculation ？ Personal understanding , The identification of the value of works of art will bring a lot of subjective color , Whether it's worth it , opinion . As a technical practitioner of blockchain , I am more concerned about NFT The technology behind it ：NFT What is it? ？NFT How is it stored in smart contracts ？NFT What are the extension directions of Technology ？

NFT What is it? ?

NFT(Non-Fungible Token), It literally means non homogenous tokens , The assets represented behind each token are different , Indivisible . In the real world , Different works of art , Different design schemes , These assets are indivisible , The corresponding value behind is also different .NFT Can better carry these values .NFT It can be understood as a specific asset registration method based on blockchain . Combined with the transparency of blockchain , Tamper proof features , It is easy to identify the creator of the asset , holder , Combined with smart contract , It can ensure that the owner of the asset has the right to operate the asset .

NFT In the smart contract storage mode ?

The earliest known NFT The project is 2017 Based on Ethereum, you Larva Labs Developed CryptoPunks project . There was no standard at that time NFT agreement , Relevant smart contract codes can be viewed at the following address ,https://etherscan.io/address/0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb#code. Part of the code is as follows ：

In the initialization code , Defined CryptoPunks Yes 10000 individual :

10000 A picture composed of heads hash Store on Chain , adopt hash The way of the chain , Make sure that the corresponding position and specific content of each avatar can not be changed at will , Once changed , New images hash And in smart contracts hash There will be no agreement ：

10000 A head , The address of the holder of each avatar is saved in the above mapping in ：

When operating each avatar , Will check whether the operator is the holder of the avatar .

Combined with the above , We can observe that ,CryptoPunks The content of each avatar in the project is determined , At the same time, the holder of each avatar can also be found . Through smart contract processing , It is very convenient to locate the address of the holder behind each digital asset , The ownership relationship is clear . meanwhile ,NFT Corresponding digital assets , Everyone can enjoy it . Creative sharing , But the ownership relationship is clear , The right to operate the asset is in the hands of the asset holder .

2018 year , With CryptoKitties The hot ,ERC721 NFT The agreement was put forward （ Please refer to https://eips.ethereum.org/EIPS/eip-721）. Defined in the agreement 721 Interface specification , It specifies the functions that the smart contract must implement and some optional implementations .

2021 year ,Larva Labs The other is based on ERC721 Projects implemented by the specification Meebits go online （ Check the details of the contract ：https://etherscan.io/address/0x7bd29408f11d2bfc23c34f18275bbf23bb716bc7#code）, Part of the code is as follows ：

In this version ,NFT Relevant content is stored in IPFS in ：

Each is defined here Meebits The specific content represented , For example, we turn on https://meebits.larvalabs.com/meebit/1：

The above content corresponds to each Meebits External display form and unique attributes . From this smart contract , It can be found that the chain is generally stored hash To ensure the immutability of assets , meanwhile , The service layer will provide specific styles of asset presentation .

Combined with the above code , We found that , In fact, we issue a NFT It is not difficult to , The key lies in NFT The value behind it ： Good ideas 、 Excellent scheme, etc . Interested students can think about , If based on existing NFT agreement , How to simplify the implementation NFT Blind box issue ？

NFT Technology extension

With NFT The application ecology of is increasingly abundant , People are also expecting its technical capabilities to meet more application scenarios , for example NFT Can it be split ？ User purchase NFT Can you support personalized creation ？

1.NFT Split ：

NFT It is indivisible in itself . To split , You can lock NFT assets , Then, based on this asset, a specific separable NFT assets , Let more people share art , Make its value flow more flexible and efficient .

Interested students can refer to the following smart contracts ：https://etherscan.io/address/0x85aa7f78bdb2de8f3e0c0010d99ad5853ffcfc63#code. Part of the code is as follows ：

The above code implements a new agent contract to handle distribution ERC20 The token of the agreement , At the same time, the corresponding ERC721 Transfer of assets to agency contracts ：

The above code ensures that if the user needs to extract the corresponding NFT When assets , It is necessary to hold all the corresponding issues ERC20, And destroy .

2.NFT Second creation ：

NFT Digital asset holders , Can I NFT Second creation on ? Based on the tamper proof feature of blockchain , Generated NFT It can't be modified , But users can be based on the original NFT To recast new NFT. Referable 【1.NFT Split 】, Put the original NFT Locked in the contract layer , Then based on it to create new NFT. Users can also remove the secondary creation part , Restore NFT To do the circulation trade .

Conclusion ：

Blockchain based NFT agreement , Turn the information flow of the digital world into a value flow . Data is the most important production factor of information internet , To give full play to its application value , We should not only pay attention to the protection of the rights and interests of data owners , Also focus on how data assets can be more flexible 、 Freer circulation .