You spent tens of thousands of dollars to buy NFT head, where in the end exist?
For NFT, a hot collector's category in the current market, many buyers are very concerned about whether the image storage method is decentralized and whether there is a risk of tampering after purchase. Generally used to store pictures is the Metadata field in NFT, so we need a simple and efficient way to help users view the Metadata in NFT.
Currently, some products already provide metadata security assessment, such as Opensea, which shows whether NFT metadata is frozen. However, because the underlying smart contracts of various NFT projects contain different function names, and the metadata storage methods of various projects are greatly different, a single query product is not compatible with all NFT products, and may even provide misleading information to users.
In this article, we'll introduce users to a more general approach to metadata validation, which is to authenticate directly through the blockchain browser.
Query NFT metadata in Etherscan
To be clear, the uniqueness of what we call NFT is determined by three basic elements. They are the public chain that deploys the NFT, the smart contract that generates the NFT, and the number of the NFT in the smart contract.
In this article, we will use Ethereum, the most abundant NFT project, and THE ERC-721 protocol of NFT as examples to introduce the method of querying NFT metadata through Etherscan.
First readers can use the most commonly used Opensea to find the NFT collection page they want to verify. Here is an example of a collection in Bored Ape Yacht Club. You can see that the details page in the lower left corner shows the three key pieces of information about this NFT: 1. Contract address; 2. The NFT number in the contract, which is also the Token ID; 3. On the public chain, namely Ethereum;
Clicking on the link to the right of the Contract Address automatically takes you to the Etherscan browser page for that Contract Address.
Click the Contract TAB on the page to view the underlying code for the Contract.
You don't need to Read the code, just click on the Read Contract TAB above to browse the queryable functions in the Contract.
Find the function tokenURI that ranks 20th in the page, which is the specific function for this NFT contract to query metadata.
Of course, the functions used to query metadata are named differently in different smart contracts. However, they usually contain fields such as URI and metadata. The good news is that most recent projects have named this function tokenURI, saving users a lot of hassle.
After clicking on the tokenURI function, we see the following interface. Enter the NFT number we want to Query in the input box above, that is, the Token ID number 6476 we just saw in Opensea, and then click the Query button below.
As you can see, in the after click the query button, the system returns a string of code: ipfs: / / QmeSjSinHpPnmXmspMjwiXyN6zS4E9zccariGR3jxcaWtq / 6476
This string of code is the metadata stored in the NFT's smart contract. It can be seen that the METADATA of this NFT is a storage link of IPFS, so it can be determined that this NFT is stored in a decentralized way. Readers can use ipFS-enabled browsers such as Brave, which returns an image of the ape represented by the NFT.
This is the entire process of querying NFT metadata with Etherscan, and it shows that there is not much of a barrier to entry for the user. But the more critical question is, how can understanding how an NFT's metadata is stored help you invest in or buy an NFT in the future?
Using a few representative NFT projects as examples, we will look at how metadata is stored in mainstream NFT projects and its potential impact on the long-term value of NFT.
Metadata storage for mainstream NFT projects
1. Do not store
Yes, there are some NFT projects that don't keep the data in a specific place at all, which means they don't have metadata at all. This type of storage was only adopted by some fossil projects in the early days of NFT, most notably CryptoPunks.
CryptoPunks
We query the contract address of CryptoPunks in the same way as before, and find that TokenURI or similar fields cannot be found. However, you can see that the fifth function, imageHash, returns a string of hash values, which is the hash value of the entire 10,000 CryptoPunk images that are stitched together into one large image. This image is currently stored on the project's official website (Image links), the user can download the image and calculate its hash value and compare it with the hash value on the chain to verify the authenticity of the image.
From this, we can conclude that the CryptoPunks project does not store any pictures on the chain, but only provides users with a picture verification method in its smart contract.It does not store images per se, but simply provides a means of on-chain verification.
Since there is no storage, then after we buy a CryptoPunks NFT, why can we accurately display the corresponding picture on Opensea? In fact, this completely depends on the artificial adaptation of Opensea website in the front end of the web page. CryptoPunks pictures do not exist on the chain, but in the centralized website cache. Therefore, the NFT of CryptoPunks must rely on a centralized organization, can be displayed normally.
Therefore, the CryptoPunks NFT investors buy is just a smart contract number, neither picture, nor other practical functions. People's recognition of him, the content of the pictures displayed on the website, more rely on the community consensus. For example, for the second CryptoPunks NFT, whether it is the second one from left to right or the second one from top to bottom can not provide a clear judgment standard on the chain, we just think that he is a representative of a certain head according to the habit.
This type of NFT project is almost extinct in the current market because it requires a very strong community consensus to support its existence and value. If there are new projects still using this "storage" way, investors are advised to buy cautiously.
Encryption cat CryptoKitties
CryptoKitties is also an NFT project with a long history. We also can't find metadata in its contract, and the only function that looks like metadata returns a null value.
After analysis, we found that CryptoKitties also did not choose to store cat pictures on the chain, but saved the basic elements of cat images on the centralized official website. All that's recorded on the chain are the unique characteristic values, or "genes," that determine how a cat looks. When a user buys a CryptoKitty, the website in charge of the front-end display will directly retrieve the characteristic genes of the NFT and generate cat pictures to be displayed to the user according to the established rules.
Therefore, the storage method of the CryptoKitties project can be summarized as follows:The cat's "genes" are stored on the chain, but the specific display content is synthesized by the server, and the display effect is completely dependent on the centralized server.
However, as CryptoKittiies is not a pure picture TYPE NFT project, its breeding function can be synthesized only by relying on the "genes" of the previous generation and the algorithms on the chain, and the rarity of the cat's appearance only depends on the composition of the genes, so the deletion of metadata in this project will not have a great impact on the game function and valuation.
The biggest advantage of the above two solutions to avoid the metadata storage problem and solve the NFT front-end display problem through other workaracks is that they save valuable on-chain storage space and reduce the complexity of project development. The disadvantage is obvious, as any web site that wants to accommodate or display relevant NFT must manually configure and cache its display, and its final display relies entirely on traditional centralized organization. If a critical node fails, the NFT that the user paid for may not be displayed properly.
Of course, this type of storage was more common in earlier NFT projects, and there are very few new NFT projects that use this workaround anymore.
2. On-chain storage
On-chain storage is also habitually referred to as"Permanent storage"Because once the user submits the data to the blockchain, the data on the blockchain is theoretically preserved forever, thanks to the imtamable nature of the blockchain. As long as we can expect the chain to run forever, the data is stored forever.
The current on-chain storage projects can also be divided into two categories, one is stored on the same public chain of the NFT smart contract, the other is stored on a private public chain such as Arweave. There are not many typical projects that use the second option, so this article will not cover much of it. The following is an analysis of typical projects stored on Ethereum.
Autoglyphs
The Autoglyphs project was also developed by the Larva Labs team that developed CryptoPunks. This product is not so well known compared with CryptoPunks, and the components of its appearance are relatively single. The following figure shows some of the product shapes.
We still use the method mentioned above to call its metadata through Etherscan, and the result returned is shown below
As you can see, the Autoglyphs NFT image elements are stored directly on top of ethereum, but need to reposition the line feeds when displayed. As a result, the display can be less affected by the front page, and the permanance and security of the stored data are better guaranteed. The downside is that ethereum's on-chain storage is expensive, making it difficult to store more complex graphics.
3. Decentralized storage
Decentralized storage technology was invented long before blockchain was invented. Although decentralized storage has the same decentralized characteristics as blockchain, decentralized storage cannot be directly equated with on-chain storage.
Some of the most popular projects that use decentralized storage for NFT metadata include the previously mentioned Bored Ape Yacht Club, which is currently the way most art NFTS are stored.
There are several significant advantages to decentralized storage:
1. Imtamability: As the domain name used to address the storage file contains the hash value of the file, it is imtamable like the blockchain, which is more in line with the spirit of encryption native;
2. Lower storage costs: For most photo projects today, basically a personal computer that can connect to the Internet for a long time can guarantee long-term storage of data. The cost of filecoin, a storage incentive layer that combines blockchain incentives, is negligible compared to the cost of storage in Ethereum.
Of course, there are some disadvantages to decentralized storage, that is, the permanence of the data storage is not very well guaranteed. For IPFS storage that does not incorporate the Filecoin incentive layer, once all the nodes responsible for the storage are offline, the stored data can still be lost.
4. Centralized storage
In this case, the metadata is stored in a centralized website server, and the metadata is stored in the link to the site. The following two days of the fire of the little penguin project as an example.
Pudgy Penguins
Below is a screenshot of the results returned by the query in its tokenURI function.
As can be seen from the query results, the project metadata returned a centralized url link, indicating that the NFT images were directly stored on the server of the project's official website. There are two main long-term risks to this type of storage. One is that the data can be tampered with by the owner of the site, and the other is that the site may lose maintenance one day and become inaccessible.
Therefore, for this type of image NFT project with centralized storage, investors need to carefully assess the strength of the project side and the willingness to maintain the operation of the project in the long term. Since this type of NFT has no application value other than the image itself, once the image returned by the corresponding link is changed, the project may revert to zero at any time.
Blockchains are often said to be immutable only when they store links to websites in metadata, and where this centralised link leads, blockchain has no idea and no control over. So this type of NFT is still structurally centralized.
We can summarize it in one law, which is:The degree of decentralization of a product depends on the most centralized link of all its components. As long as one link adopts the centralized technology stack, the whole product is a centralized product. Therefore, the image TYPE NFT that adopts this kind of storage method no longer has the basic characteristics of decentralized and imtamable blockchain.
In other words, what you're paying for is a link to the blockchain, not even a picture.
5. Doesn't matter where it's stored
It is said here that it does not matter where it is stored because the value of this type of NFT is not directly related to how the metadata is stored, and even if the NFT does not hold or modify metadata, the value of the NFT will not be significantly affected. Let's take two well-known projects that use NFT as examples.
NFT in Axie Infinity games
The following figure shows the content returned by querying the metadata of a certain Axie NFT. It can be seen that the metadata stores only a central url link, so the front display image is at risk of being tampered with.
But unlike the image NFT,The main value of an NFT as a character or item in a game comes not from the images it can display on the front of a web page, but from the features and attributes it has in the game. For example, the more damage an NFT represents, the more likely it is to win a battle, and therefore the more valuable it is. The information stored in this NFT metadata is just like the skin of a game character and will not affect its game properties even if it is modified.
This is similar to how changing the skin of a character in King of Glory doesn't have a significant impact on how the game works. Therefore, when using NFT in a game, it is the actual functionality of the NFT in the game, or its intrinsic value, that is more important than the skin properties that appear on the front end of the web.
Uniswap V3 Position NFT
Uniswap NFT metadata is stored in a very unique way and is worth highlighting. Let's look at the on-chain data using Etherscan and get the following results:
The returned data looks like unreadable gibberish, but the comment at the top gives us the encoding used: Base64. We can search any online Base64 decoding tool to parse the garbled code into the following readable results (only part of the data is intercepted due to the length) :
As you can see, at the top of the metadata is the token pair, market-making price range, token address, and statement for the market-making position. In the image field behind, the NFT image information is stored in SVG format.
Here's a little explanation of the SVG format. SVG is an image saving format, its Chinese full name"Scalable Vector Graphics". As we know, is now commonly used image format is based on pixels, our mobile phone photo save format, for example, is the lens to the color of each pixel one saved in one file, so the higher the pixel image is more clear, at the same time, the greater the storage space occupied, are more difficult to save on the chain.
The SVG format does not store images by saving pixels, but rather by saving shapes. For example, save a rectangle with a 2:1 aspect ratio, a red background color, the name of the token pair in the top left corner, and so on. The advantage of this method of image storage is that once the shape is determined, it can be enlarged and shrunk infinitely, and the storage space it occupies is not affected by the size of the graph, but only related to the complexity of the graph. Therefore, this form of storage can help to store relatively simple vector images on Ethereum at a low cost.
Since Uniswap's NFT uses the same vector image template, the NFT image style only needs to be stored once when the contract is deployed. After that, each newly minted NFT generates a new NFT image by updating the token peer core information in the graphic. Therefore, the user does not have to pay the storage cost to store the image.
Uniswap's NFT metadata storage approach is arguably one of the most exciting solutions for many NFT projects. He's juggling several important needs. One is the preservation on the whole chain, with complete decentralization and imtamability; Second, it can read all information directly from the chain without relying on the cached data stored in the front of the web page. Third, it does not involve the risk of cross-chain data invocation, and there is no need to worry about the failure or attack of the protocol using off-chain storage. As long as you trust the security of Ethereum, you can fully trust the security of the NFT. Fourth, it can save more complex images, unlike the Autoglyphs project, which can only display simple graphic information.
In the end, of course, it comes back to the source of NFT's value. In fact, for Uniswap's NFT value, where its metadata is stored, or even whether it is stored, does not affect its value at all. Because The value of Uniswap's NFT depends only on the value of the assets it can retrieve from the capital pool. As with your bank certificates of deposit, whether they are beautifully printed or poorly printed, it does not matter whether they are beautiful or not, as long as the equivalent amount of money is retrieved.
Finally, let's summarize the basic features of Uniswap NFT. Uniswap's NFT has front end display images that are stored on the Ethereum chain and can't be tampered with but can be upgraded by the team (see figure below). According to its founders, the contract for storing metadata images is the only smart contract component in the entire Uniswap V3 smart contract group that can be upgraded later. However, no matter how its subsequent image changes, it will not affect the intrinsic value of its NFT.
Source of value for NFT assets
A research paper once summarized NFT as"Metadata container"", a very penetrating summary of the current art collection NFT value sources. However, for the applied NFT mentioned above, this conclusion is difficult to provide a reasonable explanation.
We believe that current sources of value for NFT assets fall into two different categories. One is to rely on the application value of the NFT itself, such as having an NFT that can be redeemed for certain assets, or having an attribute in the game that increases your win rate, or as a ticket to an off-chain event. The value of these NFT's comes from the use value they can bring to the holder.
The other is the way value is captured in mainstream NFT projects today. That is, NFT itself has no real use value, relying only on its display content such as images stored in metadata to achieve some kind of consensus (of course, some NFT projects do not even achieve this). This type of NFT has obvious air characteristics in the long term, and we don't think it will be the mainstream NFT asset class in the future.
The current popularity of a large number of pictures of NFT products, people inevitably recall the 17 years of the flood of many air coin projects. By simply copying and modifying a version of the white paper, the project side can reap a lot of wealth by issuing money. The rise and fall of the price of air currency mainly depends on the hype, rather than its inherent use value.
A similar problem occurs in many current NFT projects, where a few thousand simple images are algorithmically generated and then sold for a large amount of money. The operation mode of this project has almost no threshold, and there will only be more and more similar projects in the future, finally making this round of NFT hype completely air coin.
Although the current hype has improved the general user's understanding of the NFT concept and promoted the improvement of NFT related infrastructure. However, due to the lack of long-term intrinsic value, with the exception of a few early header projects, more image NFT projects will have a very high risk of zero in the long run.
At the same time, users of this image-like NFT need to pay special attention to the way its metadata is stored.In many NFT products, what you see is not what you get. A large number of image NFT projects rely on more centralized trading platforms to manually "imagine" the images they display. Without the maintenance of a platform like Opensea, many users will be left with a list of links instead of pictures.
The future of NFT should depend more on application-oriented NFT that is not affected by metadata, and we can see more recent exploration of such applications. For example, a recent project casts a market-making algorithm into NFT. If users who use this algorithm can pay commissions to this algorithm NFT according to a certain proportion in the future, then the value of NFT can be equal to the discount of its future cash flow, so that its intrinsic value can be strongly supported. Whether its metadata stores a cool image or not, no one cares.
Currently, there are two tracks where the intrinsically valuable applied NFT exists. One is the financial NFT and the other is the game assets NFT. Both NFT assets are better supported by long-term intrinsic value, which is no longer based on the skin of the metadata displayed on the front of the web page, but on the actual use value to the owner. This type of applied NFT is more likely to outperform the current hype cycle in the long run than the current, much hotter photo NFT.
Welcome to join the official BlockBeats community:
Telegram Subscription Group: https://t.me/theblockbeats
Telegram Discussion Group: https://t.me/BlockBeats_App
Official Twitter Account: https://twitter.com/BlockBeatsAsia
