The alarm bell will come sooner or later.

360, which is well versed in media routines, snapped its fingers at EOS, like a depth bomb in the blockchain field, which awakened people in the circle to attach importance to the security of public chains.

The so-called "safety" always seems to be a Schrödinger state. After all, you never know if a system is safe until it is compromised.

History always repeats itself. Just like the era of PC and mobile Internet back then, new things grew wildly at the beginning of their appearance; with the arrival of nodes, security incidents broke out, and the industry began to passively pay attention to security issues; finally, security solutions became standard configurations.

At present, the blockchain field seems to be at such a node: BTG has been attacked by double spends, BEC smart contracts have major loopholes; The loopholes in the public chain undoubtedly bring out the huge influence of the blockchain and the EOS network. Several security startups have since announced funding. The issue of blockchain security seems to have been taken seriously in an instant.

In fact, security issues in the blockchain field have existed for a long time.

People who don’t understand the technology seem to be naturally confident in the security of the blockchain, and believe that assets will not be lost if they are placed on the chain. However, there have been many cases of theft of private keys from exchanges before; It is safest to keep the private key in your own hands. There are more cases of personal private key being stolen or lost on the table.

Before cracking this myth, let's talk about the ingenious design of Bitcoin.

A cryptography expert named Satoshi Nakamoto released the Bitcoin client in the mysterious "cypherpunk" mail system, creating a new type of digital gold. It does not have any issuing entity, that is, no one can issue additional tokens. Its asset value and attribution are based on consensus, and mathematics is behind the consensus. "There is a saying called Code is Law. I think the essence of code is not code, but mathematics. Mathematics is the hand of God and the truth of nature."Internet Security Company Knows ChuangyuCEO Zhao Wei lamented Odaily so much.

P2P network + PoW consensus mechanism + incentive mechanism makes this system seem unbreakable. The security boundary of this system calculated by Satoshi Nakamoto in the white paper is that someone who has 51% of the computing power can tamper with the ledger at will. However, the existence of PoW (Proof of Work) will make this attack outweigh the gains, not to mention that the holder of 51% computing power is the biggest stakeholder of the network. For his own long-term interests, he is even willing to give up the monopoly computing power to maintain the robustness of the network. Zhao Wei said: "When I first saw Bitcoin, I thought it was easy to attack, but he added proof of work, and I think it is a nightmare for hackers."

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Purchasing power cannot be adjusted by any issuer at will, and the ledger cannot be tampered with. Only you who have the private key can dispose of your assets. Believers believe that this is "truly mastering their own assets", which is a security that cannot be deprived of assets.

This is Blockchain 1.0 - Bitcoin.

This system has been in operation to this day. Even though it was terribly clogged, it was never breached.

Blockchain 2.0 failed to be so secure.

EthereumEthereum: A distributed network that can run smart contracts.

Turing-complete smart contracts bring great flexibility, but also security issues. Since then, Ethereum-based smart contracts have been repeatedly exposed to vulnerabilities. The largest of these was the June 2016 hacker attack via a combination of exploitsThe DAO project, stole tens of millions of dollars worth of Ethereum, and in October of that yearDOS attack, leading to Ethereum forks respectively. To this day, Ethereum’s smart contracts still have thousands of unresolved vulnerabilities. It can be said that the more flexible the smart contract is, the more powerful it is, the more prone to loopholes. Some new public chains even sacrifice the Turing completeness of the contract for security.

"The main reason is that the virtual machine is not designed to be used in this way. The virtual machine is not specially designed to handle assets, but public chains such as Ethereum and EOS use it to handle assets." Zhao Wei explained that for security reasons, assets and The handling of user functions should be separated, asset handling and changes should be handled by separate engines. "This process is atomic and transactional, and cannot be interrupted in the middle. For example, I am at the cash register, and you cannot ask me to wipe the table. But in the virtual machine, there are re-entry vulnerabilities."

Although blockchain 3.0 has not yet officially arrived, there are quite a few people who regard EOS as the representative of 3.0.

"In the third generation, EOS introduced the DPOS mechanism for TPS." In Zhao Wei's view, this is not only a "code security" problem similar to Ethereum's smart contract, but also abandons security in terms of architecture. It can't even be regarded as a real blockchain. "P2P network is the real blockchain."

"More and more centralization makes it easy for hackers to attack. In the network structure, if one or two nodes are fixed, the network can still continue to operate normally. But in the tree network structure, behind 21 nodes may be 7-8 Once an individual is caught by terrorists, network security no longer exists. Therefore, if network security is not safe, it depends on who has the final say. POW means that the mining machine has the final say, it is the endorsement of mathematics, mathematics is the hand of God, and intelligence is the law A kind of execution."

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The main security vulnerabilities of Ethereum (The form is from Leifeng.com）

The asset security built by Bitcoin is a security in which assets are not deprived, the value is based on consensus, and the issuer cannot control it. This is not a kind of "safety" that the public can easily understand, nor does it mean that the "safety" that the public understands has been completely eliminated here.

The security that the public understands is "I don't lose coins". In fact, the premise that assets are not stolen is based on the premise that the private key (key) is not lost. What Bitcoin gives asset owners is a right (freedom). If you want to control your own assets, you have to take responsibility for keeping the private key yourself. And most users do not necessarily have the willingness or ability to take on this kind of responsibility - it is better to store assets on a large exchange with a brand guarantee than to store them by themselves.

Security comes at a cost.

Just like Bitcoin, in order to ensure the security of the accounting system, a lot of computing power is spent. Zhao Wei believes that the openness, transparency, non-tampering, and non-deletion of the information it brings also has a great effect on security. However, on the other hand, Bitcoin's anonymity, freedom from the legal currency system, and technical threshold all pose challenges to its asset protection.

He summed up five points:

1. First of all, blockchain assets are not protected by law in most countries, and neither public security organs nor banks have recorded them.

2. The anonymity of the blockchain makes it difficult to track once the currency is lost. You don't know who stole it, and you can't prove that the asset is yours.

3. There is a certain technical threshold for protecting blockchain assets, and it is difficult for users to protect themselves; in addition, the value of assets is based on technology. Once the technology is manipulated, hackers can steal benefits at will, and the value of assets will become zero.

4. The assets on the generated and distributed database are superficially safe, but the systems of exchanges, managed wallets, mining pools and other enterprises in the industry are centralized and are the target of hacker attacks.

Compared with traditional exchanges, the KYC of digital currency exchanges is not well done. "Doing security indoors is different from being in the wilderness. (In the wilderness) it is more difficult to do security after gaining freedom. The blockchain is the wilderness."

5. The ecology is incomplete, and air coins appear frequently. The purpose of air coins is to collect money and cash out, and it is impossible to do a good job of security. On the one hand, bad coins drive out good coins, and high-quality coins that are safe and secure are not taken seriously; the mixed airdrop information steals user data, and then the information is leaked and used for credentialing, endangering the security of other assets of users.

Today, the Internet is no longer that "tool for information transmission".

Zhao Wei believes that the goal of network security has been changing with the use of the Internet. "The first step is to use it for entertainment; the second step is to communicate and socialize, then e-commerce; the third step is to deal with your assets online."

In the era of the PC Internet, the number of people who own a PC is limited, and hackers can obtain limited information after being poisoned, but the poisoning slows down and crashes my computer. In the era of mobile Internet, our daily life, fund management, and identity authentication all run on mobile phones; the theme of security has become personal privacy, leakage of funds and passwords. In the blockchain era, technology is the asset itself, and code loopholes are the loss of assets.

Zhao Wei said that he knew that Chuangyu was concerned about the whole ecology. Before that, he mainly focused on the security of wallets and exchanges, because once these two collapsed, the industry would have a huge impact. The security of the public chain is a new problem that has emerged in the past few years. "The security of the public chain is really troublesome and difficult to change. Once you want to change it, you can only hard fork it."

The asset attribute of the blockchain is destined to be eyed by hackers, and its demand for security should be stronger.

However, Chinese Internet companies have not paid enough attention to it. The report shows that China's information security investment accounts for only 1%-2% of the total investment in the IT industry, far less than the 8%-14% of European and American countries.

This is related to the stage of domestic financial digitalization and Internet development; at the same time, compared with countries such as the European Union, domestic protection of personal privacy is not enough. Zhao Wei said that the "Network Security Law" has promoted the development of the industry, but the effect needs to be gradually reflected.

"Reporting bugs sometimes doesn't pay much. So the security industry is very painful, knowing that hacking others can make a lot of money."

Security companies can do Thanos, but they don't want to bring their own Infinity Gauntlet.

Perhaps we can understand why Qihoo 360, which should be prudent and responsible for exposing vulnerabilities, will use an "epic" attitude to make them public. Since I can't "kill a thousand enemies" like Thanos to show the power of loopholes, I can only use this grandstanding method to force companies.

According to the content of the interview, we organize the content in the form of questions and answers as follows:

Odaily: From a security perspective, what do you think of the current blockchain industry, such as exchanges, public chains, wallets, etc. How does their security level compare with traditional Internet products?

 Zhao Wei: Let me first talk about the evolution of the entire blockchain.

First of all, the emergence of the Bitcoin public chain is based on three points, an equal peer-to-peer network, a consensus algorithm (PoW), and a blockchain ledger (the application of scripts). Later, it became Ethereum, which made it easier to issue coins. Smart contracts were added, and it was divided into three layers: the network layer, the consensus layer, and the contract layer. EOS even introduced DPoS to improve TPS.

After the function is complicated, it leads to some problems:

1. The network layer is not so point-to-point and equal, and the structure is tree rather than mesh;

2. Virtual machines running smart contracts have been added to networks such as Ethereum and EOS, but virtual machines are not designed to be used in this way. There should be a separate engine for handling asset changes, which should be atomic and cannot be interrupted in the middle. For example, I am at the cashier, you can't let me wipe the table.

Although the current blockchain is fast, it is definitely backward in terms of security. However, in terms of application and user experience, Ethereum and EOS are progress, you can't always carry the safe.

On top of the blockchain technology, there are mining machines, mining pools, exchanges, hot and cold wallets, etc. In fact, there is nothing special. For the user experience, they are all very centralized. Even if they want to change it, it is impossible to use a distributed architecture for the sake of capital accumulation, speed, user experience, etc.

At this time, security is no longer just the security of the blockchain, but the security of the blockchain ecosystem. For example, mining machine pools are easy to be DDos, invaded, and have their addresses changed; the security of exchanges is divided into technical, business, commercial, and compliance security; wallets are divided into centralized and decentralized, hot and cold. Protect private keys.

Safety is a wooden barrel, and any short board will bring problems.

Zhao Wei:

Zhao Wei:POW is enough. I think it is more promising to use side chains, sharding technology, and Lightning Network to speed up, but everyone wants to build a somewhat centralized chain for TPS.

So, do you think blockchain should not be applied? 

Can't say that.

There are many kinds of public chains, and there are different classifications from different dimensions. Including whether it is a P2P equal network from the perspective of network construction; from the perspective of consensus mechanism, there is proof of work and proof of equity.

The blockchain itself is a journal. It is inappropriate for individuals to keep their own data. The data cannot be kept on the machine, and it is all online.

Many blockchains today are not like the first generation of blockchains. The P2P network is the blockchain. Later, the network structure was changed in pursuit of TPS, which brought new problems. I think the chain running the smart contract is not suitable as an asset (store of value), but a certificate.

Now asset attributes are changing, so security protection is changing. We do our best to be one step ahead of the enemy in terms of security, but it is difficult, so we often take a slow step. If you see more cases, you may know it.

Zhao Wei:

Zhao Wei:There are roughly five points (already mentioned in the text).

Zhao Wei:

Zhao Wei:The background of the emergence of Bitcoin is that after the financial crisis in 2008, the U.S. government issued a large amount of currency and cut leeks. The purchasing power of currency in the hands of the people is declining, and you cannot protect your assets. It turns out that you can keep gold at home, but if you hold it yourself, the risk is very high, just like in the western United States, someone will come to snatch it at any time, this is the price of your freedom. But if you put it in the bank, the bank may send it randomly, and Bitcoin wants to turn it into a mathematical endorsement mechanism. It is very important to establish a consensus.

Blockchain is not a complex technology, it does not change productivity, but changes production relations. Blockchain technology possesses several properties: anonymous, immutable, and undeletable, which in itself promotes security. What has changed conceptually is the consensus mechanism.

Therefore, there are two aspects of security involved here. On the one hand, small African governments. Once the government collapses, the currency will not have an institution to endorse it. This is the security of purchasing power, which can ensure that you really own your assets. is a kind of freedom. Bitcoin achieves this digital gold-like freedom through a consensus mechanism.

After you get this freedom, there is a risk of hackers and security risks. How to store actually depends on your skill level and asset size. For ordinary people, it is safer to leave it to professional institutions. because:

1. There is no way to recover assets after they are lost. This is the anonymous feature of Bitcoin. This leads to a disconnect between your identity and your currency rights.

2. The blockchain means that you are your own master, and there is no way for the state to protect it.

3. The digital currency itself is facing the problem of hacker attacks.

4. Virtual assets still have inheritance issues.

5. Difficult to store. Cold wallets are slightly safer, but they are easy to lose and the batteries will leak. If it is lost, I also help the client restore it.

Zhao Wei:

Zhao Wei:Security is to protect everyone. With the expansion of Internet users, its goals have been changing: the first step of the Internet is for entertainment, the second step is business, communication, and e-commerce websites; the third step is to handle all your assets online. So security is becoming more and more important.

At present, more attention is paid to wallets and exchanges. Once an exchange collapses, the industry will have a huge impact. As for the security of the public chain, "it is really troublesome and difficult to change. Once you want to change it, you can only hard fork it."

We have been paying attention to it. Instead of announcing it, we report it to the project party. Generally, the project party will attach great importance to it, and will attach great importance to it. However, there is no reward for reporting bugs, and sometimes there is too much thunder and little rain. So the security industry is very painful, knowing that others can make a lot of money.

Odaily: You have publicly criticized EOS many times. Why are you so upset about EOS?

Zhao Wei: EOS is too much. First of all, it is a company and not a community. He collects money (fundraising), and the money is spent on an offshore company; but he does not provide services. He said that he does not care about all security issues after the release of EOS. Responsible, even does not guarantee that the EOS issued at the beginning is the currency of the public chain later; the use of the money is not transparent, and it is not explained after the money is withdrawn.

Ethereum is different, it is more transparent, and it is clear where the percentage of the money is spent. EOS is simply that I don’t necessarily have to do this thing if I charge this money.

Zhao Wei:

Zhao Wei:There is anti-quantum computing, so quantum computing is not a problem. The biggest problem is that POW consumes too much energy, but the new consensus algorithms such as POS are ruled by man and are becoming more and more centralized, making it easy for hackers to attack.

In the network structure, if you get these points fixed, the network will still continue to run; in the DPoS mechanism, there may be 7-8 people behind 21 nodes, and if they are caught by terrorists, they will do whatever they want.

Therefore, network security is not safe, it depends on who has the final say, POW means that the mining machine has the final say, the mining machine is mathematics, mathematics is the hand of God, and smart contracts are a kind of law enforcement. There is a saying that code is law, not code is law, but mathematics.

However, the code is written by programmers, and errors may occur, so formal verification is required, that is, mathematics is used for auditing. I have designed a general-purpose code audit system, but no one used it before, and now it has exploded, because now the program is the money itself.

However, there are still some problems in the design of this program. A program is actually a function, that is, whatever conditions are met, I will do what. So how do I prove that there is no problem with this function, I need to describe. At this time, a language for describing smart contracts is needed, which is a formal language.

When the smart contract is very simple, everyone can see it, but once it is complicated, formal verification is required, and no one can use formal language, so the security company will help you, and finally become a service .

Zhao Wei:

Zhao Wei:There is a standard in the industry. The level of destructive power from low to high is, leading to information leakage, DDOS attack (downtime), asset transfer. However, it is difficult to rate vulnerabilities. Some small vulnerabilities can become large vulnerabilities when combined, so we must pay attention to them.

Zhao Wei:

Zhao Wei:First of all, there is no consensus and standard for reporting vulnerabilities in the industry. Second, many times the security alliance is not a technical alliance, but a social one. For example, cracking down on air coins requires the use of national laws and social support, legally requires evidence collection, and the cooperation of public security departments. In fact, reporting a loophole is a small matter from the perspective of the entire industry, because some problems can be solved by technology and management, but more of them are actually social problems, which are the big problems.

Zhao Wei:

Zhao Wei:Our basic security facilities are not well developed. This is related to people's awareness. Everyone still lacks risk awareness and will not invest in security. European and American companies will put a certain percentage of their money on safety, but Chinese companies save as much as they can in this regard.

I am Lu Xiaoming, editor of Odaily. I am exploring the real blockchain. Please add WeChat lohiuming for breaking news and communication. Please note your name, unit, position and reason.

I am Lu Xiaoming, editor of Odaily. I am exploring the real blockchain. Please add WeChat lohiuming for breaking news and communication. Please note your name, unit, position and reason.