This article is reproduced from Nervos Blog, author: @radicalizedpleb, @matt_bitcoin. Original English text:

https://www.nervos.org/knowledge-base/web5-extra-decentralized

TBD[1], founder of Twitter, is a brand new layer of Internet identity and trust, one of his first attempts in the cryptocurrency field, aiming to operate completely based on a peer-to-peer architecture. and combined with existing Web2 services.

Many people think that TBD sounds like Web3 decentralized identity service ENS[2], but Dorsey doesn't think so. As a determined bitcoin believer (now the word has become synonymous with cryptocurrency skeptics), he felt the need to separate from the mainstream and ensure that TBD is never seen as another Web3 project.

Specifically, Dorsey realized Web3—a vision of decentralized Internet built on open protocols and blockchains, including identity, finance and Social layers - not the system he pursues.

He recognized that the reality of Web3 is fundamentally contrary to its vision: it is incompatible with the existing infrastructure of the Internet and is committed to completely replacing the latter.

Figure: Definition of Web5 (Source: TBD PPT[3])

Because TBD's claimed core goal is "decentralization" and never compromises, Dorsey chose to build this system on Bitcoin. In his opinion, this alone would be enough to make TBD “not belonging to Web3”, so it is necessary to create a new term for such systems.

For this reason, Dorsey half-jokingly proposed the term "Web5", which was a mockery of Web3 on the one hand, and a tribute to HTML5[4] on the other hand . HTML5 isThe foundation of today’s Internet is also the last major technological attempt to promote the evolution of the Internet 15 years ago.

From TBD's white paper [5], Dorsey treats Web5 as a Bitcoin serves as the basic consensus layer and Lightning Network serves as a peer-to-peer network of payment networks. It revolves around three pillars: 1) autonomously owned decentralized identifiers, 2) verifiable credentials, and 3) decentralized network nodes used to store data and forward messages.

"On today's network, identity and personal data have become third-party property. Web5 will bring decentralized identity to your application and data storage. It allows developers to focus on creating an excellent user experience while returning ownership of data and identity to individuals.” TBD official website wrote.

In conjunction with Twitter file [6] (a series of internal documents that reveal how Twitter companies are forced to censor sensitive content) with TBD’s goal, we have reason to It is believed that Dorsey essentially wants to build "free technology".

His vision for this technology is typically reflected in Nostr[7] - an open decentralized, censorship-resistant message transmission protocol designed to deal with the current situation Designed for content review and review issues on centralized social media platforms.

For those who are new to learn, Nostr works similar to blockchain: each user generates a private key (needs to be confidential) and uses its public key Identity ID. All messages (called "notes") are encrypted and signed by their creator and can be verified by others.

Nostr does not rely on a single platform to store user data, but stores and forward messages in accordance with simple and open rules through an independent server (called "relay") . Since users can choose any relay or self-built node, no central authority can effectively review or delete content. The protocol itself is extremely concise and only defines the message format, signature and publishing method. Developers can build additional functions on this basis, such as private messages, image support, etc.

With witnessing how centralized social media companies work, Dorsey is obsessed with another vision: taking control of web applications from enterprises and manipulated The node is handed back to the user. He is about NosTr's interest and support suggest that we have the opportunity to transcend "server ownership" of Web2, and it is disturbing that this model has penetrated into Web3.

Now, although we have no way of knowing if Dorsey was ironic when he created the term "Web5", it is certain that he did catch it Some keys. Although TBD has never released a product and has ceased operations [8], Dorsey’s insight into Web3 flaws remains accurate and predictable.

However, his vision for Web5 does not have to be limited to Bitcoin and the Lightning Network [9].

In our opinion, Web5 has a far greater significance than its components, and it is not only a "peer-to-peer network" dedicated to Bitcoin consensus or around decentralization Identifier-building framework.

Going further, Web5 is not a semantic "brand reshaping" or a sensational marketing strategy, but a substantial turn in the Internet industry's return to its roots.

We see Web5 as a mesh structure composed of point-to-point networks, connecting various PoWs (Proof of Work) and UTXO consensus layer, channel network, and other A system that has not been conceived yet. More abstractly, Web5 is a thriving decentralized application (dApp) ecosystem built on this peer-to-peer mesh structure.

Topological structure of decentralized and peer-to-peer networks (Source: CKB Eco Fund[ 10])

The underlying architecture is the core difference between Web5 and Web3.

Web5 is built on a network of truly decentralized, point-to-point topology, and is a direct result of the adoption of the PoW consensus and UTXO model. Instead of treating blockchain technology as its only core, it conceives a series of open Internet protocols to enhance the latest cryptographic primitives, jointly push the Internet into a new era.

In contrast, Web3 failed to fulfill its commitment to decentralization, censorship resistance, licensing and self-custody of data and assets, and its root cause lies in its underlying architecture defect, especially decisions that choose PoS (Proof of Stake) and Account models.

The current situation of Web3

Now Web3 is a collection of countless "nominally decentralized" networks. Since the rise of MetaMask[11] and Infura[12] in 2017, these networks quickly turned to the “client-server[13]” topology.

Despite arduous research and engineering efforts, we concluded that this result is an inevitable product built on the PoS and Account models.

While we respect the principled efforts made by many people to combat this trend, we do not believe that flaws in the client-server topology can be fixed. Before we can analyze the reasons in depth, let us first examine the current situation of Web3.

In February 2009, Satoshi Nakamoto wrote in his post [14]: "The fundamental problem of traditional currencies is all the trust it needs to operate."

Observing today's Ethereum, "trust" seems to have increased. Although staking pool operators and block builders are not trusted third parties (TTPs) in the strict sense, they have clearly become increasingly important privileged roles.

The percentage of ETH pledged by each entity as a total pledge (Source: dune.com)

Liquidity staking protocol Lido[15] controls about 28% of total ETH staking, while Coinbase[16] controls about 11%, which triggers governance Rights and verification rights are concentrated on the concerns of a few industry giants. Beaverbuild[17] and Titan Builder[18] produced approximately 89%[19] of Ethereum blocks, further exacerbating concerns about the ability to combat censorship and control of maximum extractable value (MEV[20]).

In addition, although the Ethereum base layer is "sufficient in many metrics - especially compared to most Web3 projectsdecentralized, but its community-selected scaling-out path has spawned systems that clearly rely on the assumption of trust.

These systems rely on centralized infrastructure providers that act as "servers", while users become "clients" that rely on these servers to obtain network functions and access rights. This architecture is no different from traditional Web2, and is different from The decentralized goal that Web3 initially pursues.

Taking Rollup[21] as an example, Reliance on centralized sorters creates a serious bottleneck. Ideally, a single entity has full control over transaction sorting and packaging, and users have to trust their honest behavior - this goes against the cryptocurrency’s “no trust” purpose. Worst In case, the entity can completely stop the chain operation. For example, the Ethereum Layer 2 project Linea suspended the sorter this year due to an attack on a decentralized exchange in the ecosystem [22].

What's worse, Linea is not an exception. Almost all Ethereum Rollup operates centrally, and its operators can review transactions or stop the chain from running indefinitely. If a chain can be suspended at will, then it What is the significance? Traditional centralized databases obviously perform better, so why do you need to run a chain?

Even if we ignore these hidden dangers, naively assume the current Web3 foundation Trusted third parties of a facility are trustworthy, and we still cannot avoid the fact that, as Nick Szabo pointed out years ago, these third parties are inherently security vulnerabilities [23], and countless security incidents have repeatedly proved this.

For example, in July 2023, the cross-chain protocol Multichain lost more than US$125 million due to suspected internal personnel. The source of the vulnerability [24] lies in the fact that its CEO Zhao Jun controlled the platform Some multi-party computing (MPC) keys were arrested by police. A similar situation occurred a year ago at Ronin Bridge of Axie Infinity, where North Korean hacker group Lazarus stole more than $600 million by controlling the private key of 5/9 validator User funds[25].

Untrust and securityIn addition to the full problem, horizontal scaling (i.e., execution through side chain shunt transactions) also leads to severe liquidity fragmentation and infrastructure cost issues. There are dozens of Ethereum Layer 2s, most of which have become ghost chains because they cannot attract enough liquidity.

The total TVL of the top two Layer 2 projects Arbitrum and Base (32.12 billion USD) exceeded the total of TVL, the remaining 18 Layer 2 projects ($11.43 billion). (Source: L2Beat.com)

Liquidity attracts traders, trading volume generates liquidity, and the combination of the two attracts dApp developers. The fragmentation of liquidity has caused Layer 2 to fall into the network effect dilemma: the chains that were the first to break through the critical point continue to grow, while the rest of the chains gradually wither, ultimately leading to the concentration of liquidity and user activities among a few winners.

Although these systems are called Rollup, they are still blockchains with scarce block space. This means that successful Layer 2 will still encounter the same scalability and fee fluctuations as the underlying chain, which in turn will lead to Layer 3 requirements with more complex security assumptions.

The increase in the number of chains means higher infrastructure costs—after all, someone needs to maintain all the Rollups. Even after the Ethereum EIP-4844[26] upgrade introduces data blocks (blobs) and reduces Layer 1 data availability (DA) costs by 100 times, the average monthly cost of running a Rollup [27] is still as high as $10,000 to $16,000. (Suppose there are 2 million transactions per month).

Under the same assumption, the cost of Layer 1 alone is $25,000, while the cost of using alternative DA layers such as Celestia[28] or EigenDA[29] is cheaper Several orders of magnitude. Unfortunately, for many Layer 2, the fees paid by users are not enough to cover infrastructure costs, which means that the "server" operators are responsible for their own expenses. This financial burden raises the threshold for new participants, gives strong capital entities the advantage and further aggravates centralization.

In contrast, the PoW+UTXO chain extends vertically (adding payment channels or states on top of the base layerChannel) realizes capacity expansion. Verification remains low-cost and easy to access, and users can run full-node or light-node clients on normal hardware, ensuring extensive network participation. Through UTXO management status, users only need to verify transactions related to themselves, without relying on centralized middlemen.

Protocols such as Lightning Network, Ark[30] and RGB++[31] are examples of this path. Users can directly establish payment channels, and their security is anchored to the PoW consensus at the base layer. There is no need for cross-chain bridges, no centralized sorters that may become points of failure, which maintains the network's point-to-point topology and ensures true decentralization and censorship resistance.

How did Web3 get to this point?

To understand why we build Web5, we need to clarify where Web3 went wrong. The best way is to examine design choices in Ethereum's history.

First, we must clarify that we have no prejudice against Ethereum (or any other chain). Instead, we just use it as an example to analyze the shortcomings of the PoS+Account model.

In this category, Ethereum is the most decentralized chain at the technology, concepts and community levels, and is also the birthplace and main construction platform of Web3 narrative. If you use other chains as an example to criticize Web3, it is obviously unfair. Furthermore, we believe that the Ethereum community’s efforts to achieve its Web3 goals are sincere, and its failures stem from decisions a decade ago.

The first error of Ethereum

The first error of Ethereum comes from it Initially attempted to turn blockchain into a "world computer". In this article [32], we explain in depth why this is fundamentally a bad idea, so here we only give the conclusion that blockchain is used for verification, not for computing.

When Bitcoin developer Gregory Maxwell pointed this out more than nine years ago [33], Vitalik Buterin retorted fiercely [34].

Looking at the current situation of Ethereum, it seems that the argument of "everything goes on the chain" has been abandoned. Any and all attempts to expand the world computerAll are through “extending on another chain”, the more well-known Rollup-centric roadmap [35].

In other words, the Ethereum community has abandoned its original philosophy and turned to a more technologically conservative "modular blockchain" path. Today, the base layer is used to verify and final settlement, while adjacent chains or Layer 2 are responsible for transaction processing.

The second error of Ethereum

However, this turn failed to establish a peer-to-peer The root cause of the network is Ethereum's second architectural error: abandoning Bitcoin's UTXO model and adopting the Account model.

At that time, Vitalik proposed two arguments [36] to justify this transition: 1) "UTXO is theoretically complex and even more so in implementation ”; 2) “UTXO is stateless and difficult to support complex applications that require state management (such as various smart contracts).”.

Although these arguments might have been established at the time and regarded as important innovations, the industry has since made great progress. Statefulness — Maintaining and updating the "state" of the blockchain or a collection of all current data, balances and conditions generated by past transactions — is indeed necessary for calculations, but the Account model is not the only path to implement statefulness.

In 2017, Cardano launched the extended UTXO (eUTXO[37]) model; in 2019, Nervos proposed the Cell model[38]—a stateful universal UTXO model; Recently, BitVM developers have even implemented state calculations on Bitcoin through Taproot.

Looking back, choosing an Account model over a UTXO model seemed like a decision that focused on short-term: although it facilitated developers to quickly build dApps, it sacrificed many UTXO models. Natural advantages.

One ​​of the most critical is how the UTXO model achieves true ownership of assets and data—which happens to be the core goal that Web3 and Web5 jointly declared.

UTXO model does not have an account in the traditional sense, but through the address andUnspent transaction output (UTXO) to track asset ownership and transfers.

UTXO is a received but not yet spent cryptocurrency unit associated with the address that specifies who can spend them. In this model, the user manages the funds corresponding to UTXO through the private key. The sum of these UTXOs is the available funds for users, and there is no need for traditional accounts throughout the process.

In contrast, the Account model, the account is divided into external accounts (EOA, controlled by a private key, and can initiate transactions) and contract accounts (CA, that is, smart contracts, and cannot be proactive. Initiate a transaction, consisting of code and data). The problem is that in the Account model, all non-native assets (tokens in Ethereum except ETH) are managed by CA. This means that non-native assets are second-class citizens in this model. The token balance displayed in the user's wallet does not represent actual ownership, and these tokens are managed by the CA controlled by the EOA that created them.

Realistic cases best illustrate the seriousness of this problem. LayerZero[39] Co-founder and CEO Brian Pellegrino recently pointed out in a tweet [40] that there is a serious vulnerability in the token contract of the cross-chain interoperability protocol Across[41]: a function in the token contract allows the contract owner. Transfer tokens from any wallet at any time. In short, the Across team can steal tokens from any user who holds these tokens.

What's worse is that such cases are not isolated cases. Many token contracts include similar functions, allowing contract owners to issue additional tokens, destroy tokens at will, or review and confiscate user assets.

Centralized stablecoin issuers have built-in such features by default (as necessary compliance means) so that they can confiscate suspected illegal acquisitions (such as through vulnerabilities or thefts). ) tokens.

In the UTXO model, all assets are directly controlled by the user's private key and are first-class citizens. Taking Nervos CKB using the stateful UTXO model as an example, the token contract only defines token logic (such as "total supply of 1 million" or "50 pieces are issued per block"), and records the asset data of the user's balance ( For example, "Alice holds 100 tokens") is stored in a cell directly controlled by the user (which can be regarded as a stateful UTXO). This means that, evenThe token contract was attacked, and hackers could not steal user assets.

The third error of Ethereum

The third error of Ethereum is to give up PoW switched to PoS. Reasons for supporting this decision [42] include "PoS's significant advantages in security, reducing centralized risks and energy efficiency" and "higher security at the same cost". But for many readers, it is now obvious: PoS cannot replace PoW. If you still have doubts, please refer to "Why We Follow Satoshi Nakamoto [43]" or "Why the World Needs Miners [44]".

In addition, time provides evidence to refute these arguments. Last year, Vitalik himself wrote a long article [45] to warn of the inherent centralized risks of PoS. The following excerpts summarize its core point:

"One of the biggest risks of Ethereum L1 is that PoS is becoming centralized due to economic pressure. If you participate in the core PoS The mechanism has an economic effect on scale, large stakers will naturally dominate the network, while small stakers will exit and join the big pool. This will lead to an increase in crisis risks such as 51% attacks and transaction reviews. In addition to centralized risks, there is also a risk of value extraction. : Minorities may seize the value that should belong to Ethereum users. ”

Although Vitalik proposed several Ethereum-specific solutions in the article, We don't think this helps. Centralized power and dependence on trusted third parties are natural attributes of the PoS+Account blockchain.

In addition, the use of PoS consensus and Account model will trigger a series of chain reactions, which will ultimately make these networks form a client-server topology, which is closer to a fully centralized Web2 system, not Web3 ideal form.

So the only way to achieve true decentralization, censorship-resistant, license-free and self-hosting of data assets (Web3's goal) is to build PoW+UTXO based The system's point-to-point network (Web5). To understand this, we need to deeply analyze the core differences between the PoS+Account blockchain and the PoW+UTXO blockchain.

PoS+Accountvs. PoW+UTXO

There are significant differences between the PoS+Account system and the PoW+UTXO system, and the secondary impact of its implementation is more profound. Some seemingly subtle design choices may ultimately lead to extremely different shapes of the chain.

We will verify the following assumption through several dimensions: a chain that selects a PoS or Account model can never form a flat, true point-to-point network.

State difference

The first dimension that supports our assumption is PoW+UTXO and The difference in state assumptions of PoS+Account chains.

For example, in a UTXO-based system, transactions are stateful and contain inputs Two parts and output. Each transaction clearly defines which UTXOs consume and which new UTXOs are generated, that is, carrying all the status information needed to update the ledger. However, the on-chain environment is stateless in nature, and transactions can only affect the UTXO they reference directly, and cannot modify other parts of the ledger.

In contrast, in Account-based systems, transactions are stateless—only Contains operation instructions (i.e., actions or method calls that are expected to be executed) without explicitly specifying the current status of the relevant account. The on-chain environment is stateful, and any transaction can modify the status of any account or contract. For example, a smart contract can interact with multiple accounts and change various state variables, resulting in a highly interconnected system state.

In UTXO-based systems, transactions created by users clearly specify the content of the ledger change; while in Account-based systems, users rely on blockchain nodes to calculate these change.

In terms of consensus mechanisms, PoS consensus is stateful. Verifying consensus requires access to the on-chain data, especially the current set of validators, their staking status and random numbers. As the validator set changes dynamically, nodes need to continuously track these states to verify the new block.

And PoW consensus is essentially stateless: nodes only need to verify the proof of work in the block header to confirm the validity of the blockchain without additional on-chain state information.

The difference in these state assumptions means that in the PoS+Account model, user verification transactions need to be tracked Global state, which requires running the full node.

However, the state of the PoS+ Account model significantly increases the storage and computing burden of the full node. The node needs to perform all independently Smart contracts to verify transactions, track changes in the collection of validators and their stakes, and process authentication, proposals, and other data related to block verification. This causes nodes to store and calculate additional status information.

Data comparison can intuitively reflect the difference: the minimum requirement for running Ethereum full nodes is 2TB solid-state drive, 16GB of memory, The seventh generation or higher Intel processors; while running the full node of Bitcoin only requires low-end CPU, 2GB of memory and at least 15GB of available disk space. In addition, Ethereum is facing a state explosion problem [46] - its state The growth rate is 3.5 times that of Bitcoin, and the old state data cannot be pruned, which means there is no upper limit for state growth.

Because the PoS+Account chain runs the full node The hardware requirements are high, and there are few actual operators. At the same time, due to the implementation complexity and security trade-offs of the PoS+Account model, light clients that really do not need trust almost exist, and users are forced to rely on Alchemy[48] and Infura [49] Equally centralized RPC services access the blockchain.

In other words, the PoS consensus and Account model make full nodes difficult to run and minimize trust The light client becomes unfeasible, which leaves users with no choice but to read and update state through a few centralized RPCs and APIs. This dependency has spawned a client-server network topology, with the centralized Web2

So, "Web3" reproduces the Web2 problem it originally wanted to solve: lack of security, privacy and censorship resistance. Services RP for most Web3 usersC providers can review transactions, which were confirmed in the OFAC sanctions on TornadoCash incident [50].

These RPC providers also collect user data, including blockchain addresses and IP addresses. Additionally, since most users’ traffic relies on these providers, if there is a problem with their centralized infrastructure or offline, the entire user base (especially “massive adopters”) will not be able to access the blockchain, such as Infura in 2018. Congestion caused by CryptoKitties leads to service outages [51].

In contrast, the PoW+UTXO system is easy to implement with full nodes, SPVs and light clients, so users do not need to rely on trusted third parties to verify transactions. This promotes direct (and thus more private) approaches to blockchain participation and peer-to-peer network topology, enabling true decentralization.

Deterministic difference

Blockchain is essentially a replicated deterministic state machine, This makes it a "single source of truth" recognized by everyone.

PoW+UTXO and PoS+Account systems have different deterministic expression methods, resulting in differences in network topology, especially in validator election, block time and Finality.

In PoS systems, validator elections are deterministic—Verifier press Preset rules take turns to get out blocks. Although this method improves efficiency, it introduces vulnerability: the validator's IP address is exposed, and the attacker can launch a DDoS attack on a specific validator, causing the network to be paralyzed during the blocking period. In addition, validators must understand each other and cooperate properly, because the health of the network depends on this. More importantly, deterministic blocking puts the validator in a favorable position to draw economic rent from the user. Specialized companies use resources and income to expand the scale of pledges, continue to obtain block rewards and MEVs, forming a positive cycle of "the richer becomes richer". This trend is further exacerbated by the centralization of MEV supply chains and block builders.

Which in the PoW chain, validator elections are non-deterministic. Before the block is mined, no one knows who will be generated by the next block, which facilitates point-to-pointEquality of nodes in the network. Consensus sets are also non-deterministic. Miners can freely join or exit the network, and any node can generate blocks. No miner is indispensable for the continuation of the chain. This is impossible in PoS because the consensus set of PoS is deterministic and some validators must be present to advance the development of the chain.

PoW network is therefore more robust, with no nodes in a favorable position, and no nodes are guaranteed to have the opportunity to use users for personal gain.

Web5's future potential

A network composed of PoW+UTXO chains is still a fantasy for many people. Web3 has become an industrial machine that continuously produces new systems to solve Ethereum-derived problems. Although some thinkers are beginning to understand the subtleties of PoW+UTXO, Web3 is still entirely built on the PoS+Account model.

While Jack Dorsey failed to lead the TBD project to the Promised Land, ironically, the future of Web5 is indeed TBD (to be determined, to be determined).

Even Satoshi Nakamoto imagined a world composed of huge blockchains and industrialized nodes/miners. Today’s Web3 universe contains these; however, we are always thinking about the chain: which RPC does MetaMask point to? Which chain does the asset bridge to? Does the address format comply with the specifications? etc.

In this industry where every technical concept details seem to have tokens and teams, blockchain is regarded as the true commitment layer of off-chain systems, but instead It is a whole new field. Thankfully, our vision for Web5 is already underway.

Although it started with controversy (perhaps "rgbp2p" is a better name), RGB++[52] is leading the Web5 wave, integrating without trust Bitcoin and Nervos CKB, no cross-chain bridge or suspicious security mechanisms are required. Dogecoin's support [53] is under development and is expected to be connected to PoW+UTXO chains such as Kaspa[54] and Ergo[55] in the future.

Polycrypt[57] The team has worked on the State Channel Network for nearly seven years and has recently released cross-account and UTXO models with support for 8 chains, including Ethereum, Polkadot, Dfinity, Cardano, Cosmos, Stellar, Fabric and CKB.

In the wave of BitVM[58] and Bitcoin revival, as Taproot Assets[59] matures, off-chain revival is also kicking off. Teams such as Ark[60], Mercury[61] are exploring new possibilities for off-chain computing in Bitcoin native.

Conclusion

Implement Web3 claims The only path to truly decentralized, censor-resistant, license-free and self-hosted data assets is to build a network of point-to-point topology. So far, only the PoW+UTXO system is possible.

In the PoW universe, blockchains have extremely low success rates, and they are more like fleeting meteors than convenience stores. These miracles or beautiful accidents are only used for consensus and final settlement, and everyone can participate in the operation. Verification is kept low cost and easy to access, and users can run full nodes or light clients with normal hardware.

Enhance throughput by vertical scaling (adding payment channels or state channels at the base layer). Status is managed through UTXO, allowing users to verify only transactions related to them without relying on centralized intermediaries.

The road to innovation is always full of uncertainty, and the future of Web5 is no exception. But as Nervos and Nostr client developer Retric said in this article [62]: "This is a lively community driven by values ​​such as freedom, decentralization and open communication. It's not just technology - It's a fortunemove. ”

After ten years of Web3 observation, we rarely see surprises and are now ready to get rid of these shackles. We are ready for uncertainty. Hope you That's the case.