I was asked several times yesterday about the relationship between ERC-6551 and AA, and only after chatting did I find that there are various deviations in everyone's understanding of it. I have recorded some analogies used in today's discussion, hoping to help everyone understand. As usual, this small essay is not a serious technical article, and inaccurate analogies will be used for ease of understanding.
Quickly understand ERC-6551
First of all, ERC-6551 is not a Token standard. It is not a concept of the same category as ERC-721, but more like ERC-4337—yes, you heard it right, it is more like an AA standard, but it is an application layer. standard. If it is the most similar, it should be (private goods warning) ERC-7093 social recovery standards are all considering how AA should be used. So you can say "UniPass v2 is a 4337 / 6551 / 7093 compatible AA account", but there is no such thing as "ERC-6551 compatible NFT".
Seeing this, you may have a question mark on your face: Didn’t you say to bind an account to each NFT, how did it become the AA standard? This is the power of narrative - the same thing, described from different angles, the audience's perception will be very different.
From the perspective of NFT Holder: I have an NFT in my address A, which has an associated address X, and I can use A to control X transfers; when I transfer the NFT to address B, A loses the ability to control X, At the same time, B has obtained this ability, so account X is bound to this NFT.
From the perspective of the AA account developer: implement an NFT-associated authentication method in the AA account, if the Key that initiates the transfer request is an Ethereum address, and the address has a pre-registered NFT, then the authentication passes to unlock the account.
Of course, the effect of "innate binding" can also be achieved by encoding the unique ID of the NFT when generating the address. If you happen to be a small partner who can write contracts, you can actually quickly implement an AA account with similar functions through the Safe Module.
In fact, if you read its Abstract, you should be able to easily find this conclusion:
This proposal defines a system which gives every ERC-721 token a smart contract account. These token bound accounts allow ERC-721 tokens to own assets and interact with applications, without requiring changes to existing ERC-721 smart contracts or infrastructure.
Explain ERC-6551 with an analogy
I believe everyone has understood that ERC-6551 describes a kind of AA account rather than NFT, so then we will use the best prop of AA science popularization-smart door lock to explain by analogy.
First, we compare the private key to a fingerprint. They respectively correspond to the "identity" concepts of the Crypto world and the physical world. If they are obtained by a third party, others will not be able to tell whether it is "self" or "others" who are doing the operation, so generally we will not share them with others.
Then let's start with the simplest AA account: an AA account controlled by a single key (EOA), such as a single-signature Safe account. Its unlocking logic is to verify the signature of the key, and if it matches, the account can be unlocked; analogous to a smart door lock, it is the logic of unlocking with a fingerprint. This kind of logic that is strongly bound to identity is actually inappropriate in some scenarios, such as bathroom lockers. people".
Finally, we mapped "the person took the key card to open the locker and got 100 dollars" to "the address held the NFT to unlock the binding address and transferred 100 USDT" - congratulations, you already understand the basic principle of ERC-6551 !
ERC-6551 uses each ERC-721 NFT as a key card, and then equips it with a locker.
summary
Is there a feeling of "stopping suddenly"? Because it is really not complicated to use an analogy, the actual Spec also has some settings similar to the Entry Point in ERC-4337, and the processing method for "circular references" (that is, putting the key card in a locker). Everyone understands that the basic principles have nothing to do with it, so I won't get into it.
Although the idea of this standard is relatively simple, it is to change the narrative perspective, but sometimes changing the perspective will make the design of some scenes more natural. For example, the logic of wearing NFT game equipment can become "call the equipment NFT to the binding address of the character NFT "(Thanks to Stitch for the case). Therefore, ERC-6551 can be said to be a protocol that greatly helps the popularization of AA. I hope that there will be more and more similar protocols or use cases, so that everyone can feel the charm of AA.
Finally, if you are a little unfamiliar with the concepts of AA/EOA, here is anexplanation of the terms I wrote before for reference.
