区块链pos机制,区块链pos什么意思

区块链POS机制是一种分布式共识机制，它可以帮助网络中的参与者达成共识，从而实现更高效的交易。POS机制的全称是“Proof of Stake”，即“权益证明”，它是一种比特币网络中的新型共识机制，它可以替代传统的工作量证明（PoW）机制，从而提高网络的安全性和效率。

权益证明（PoS）是区块链POS机制的核心，它是一种比特币网络中新型的共识机制，它可以替代传统的工作量证明（PoW）机制，从而提高网络的安全性和效率。权益证明机制的基本思想是，参与网络的节点可以通过投票来达成共识，而不是通过计算来达成共识。参与节点可以把自己持有的货币作为抵押，以此来获取投票权，从而参与网络的共识过程。

抵押投票（Delegated Proof of Stake）是一种基于权益证明的投票机制，它可以让网络中的节点把自己持有的货币作为抵押，以此来获取投票权，从而参与网络的共识过程。抵押投票机制的优势在于，它可以让网络中的节点更容易参与共识过程，而不用担心计算能力的限制。此外，抵押投票机制还可以增加网络的安全性，因为节点必须把自己持有的货币作为抵押，从而有效防止节点恶意投票。

代币激励机制（Token Incentive Mechanism）是一种激励机制，它可以帮助网络中的节点更好地参与共识过程，从而更好地保护网络的安全性和效率。代币激励机制可以通过发放代币来激励网络中的节点参与共识过程。这些代币可以用来支付节点的计算费用，也可以用来激励节点参与共识过程，从而更有效地保护网络的安全性和效率。

总之，区块链POS机制是一种分布式共识机制，它可以帮助网络中的参与者达成共识，从而实现更高效的交易。它的核心是权益证明机制，它可以让网络中的节点把自己持有的货币作为抵押，以此来获取投票权，从而参与网络的共识过程。此外，还可以通过抵押投票和代币激励机制来提高网络的安全性和效率。

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1. Several major blockchain consensus mechanisms and their advantages and disadvantages

First of all, no consensus mechanism is perfect. Each consensus mechanism has its advantages and disadvantages, and some The consensus mechanism is designed to solve some specific problems.
1.pow (Proof of Work) Proof of Work
One sentence introduction: The more you work, the more you receive.
Relying on machines to perform mathematical operations to obtain accounting rights, the resource consumption is higher than other consensus mechanisms and the supervision is weak. At the same time, each time a consensus is reached, the entire network needs to participate in the operation. The performance efficiency is relatively low, and fault tolerance is not allowed. 50% of the nodes in the entire network are faulty.
Advantages:
1) The algorithm is simple and easy to implement;
2) Nodes can reach consensus without exchanging additional information;
3) Destroying the system requires a huge cost ;
Disadvantages:
1) Waste of energy;
2) Block confirmation time is difficult to shorten;
3) The new blockchain must find a different hashing algorithm , otherwise you will face Bitcoin’s computing power attack;
4) It is easy to produce forks and need to wait for multiple confirmations;
5) There is never finality, and a checkpoint mechanism is needed to make up for finality;
br />2.POS Proof of Stake, Proof of Stake
In one sentence: the more you hold, the more you get.
The main idea is that the difficulty of obtaining node accounting rights is inversely proportional to the equity held by the node. Compared with PoW, the resource consumption caused by mathematical operations is reduced to a certain extent, and the performance has been improved accordingly, but it is still The method of obtaining accounting rights based on hash operation competition has weak supervision. The fault tolerance of this consensus mechanism is the same as PoW. It is an upgraded consensus mechanism of Pow. According to the proportion of tokens and time occupied by each node, the mining difficulty is reduced in an equal proportion, thereby speeding up the speed of finding random numbers
Advantages: shortened to a certain extent The time it takes to reach consensus; there is no longer a need to consume a lot of energy for mining.
Disadvantages: Mining is still required, which essentially does not solve the pain points of commercial applications; all confirmations are only probabilistic expressions, not deterministic things. In theory, there may be other attacks. For example, the DAO attack on Ethereum caused a hard fork of Ethereum, and the emergence of ETC as a result of the incident actually proved the failure of the hard fork.
The principle of DPOS is the same as that of POS, except that some "people's congress representatives" are selected.
The BitShares community first proposed the DPoS mechanism.
The main difference from PoS is that nodes elect several agents, who verify and keep accounts. Its compliance supervision, performance, resource consumption and fault tolerance are similar to PoS. Similar to board voting, currency holders vote for a certain number of nodes to perform verification and accounting on their behalf.
The working principle of DPoS is:
GoCentralization means that each shareholder has influence according to the proportion of his shareholding, and the result of the vote of 51% shareholders will be irreversible and binding. The challenge is to achieve 51% approval in a timely and efficient manner. To achieve this goal, each shareholder may grant his or her voting rights to a representative. The top 100 representatives with the most votes take turns to generate blocks according to a set schedule. Each representative is assigned a time slot to produce blocks. All representatives will receive compensation equal to 10% of the transaction fees included in an average block. If an average block contains 100 shares as a transaction fee, a representative will receive 1 share as compensation.
Network delays may prevent some representatives from broadcasting their blocks in time, which will cause the blockchain to fork. However, this is unlikely to happen because representatives of the manufacturing block can have direct connections with representatives of the pre- and post-manufacturing blocks. The purpose of establishing this direct connection to the rep after you (and perhaps the rep after you) is to ensure that you get paid.
This mode can generate a new block every 30 seconds, and the possibility of a blockchain fork under normal network conditions is extremely small, and even if it occurs, it can be resolved within a few minutes.
Become a representative:
To become a representative, you must register your public key on the network and then be assigned a 32-bit unique identifier. This identifier is then referenced in the "header" of each transaction data.
Authorization votes:
Each wallet has a parameter setting window in which the user can select one or more representatives and rank them. Once set up, every transaction a user makes will move votes from "Input Representatives" to "Output Representatives". Generally, users will not create transactions specifically for the purpose of voting because that will cost them a transaction fee. But in an emergency, some users may find it worthwhile to pay a fee to change their vote in a more positive way.
Keep representatives honest:
Each wallet will display a status indicator to let users know how their representatives are performing. If they miss too many blocks, the system will recommend the user to switch to a new representative. If any representative is found to have signed an invalid block, all standard wallets will require the election of a new representative before each wallet can conduct further transactions.
Resisting attacks:
In terms of resisting attacks, because the power rights obtained by the top 100 representatives are the same, each representative has an equal voting right. Therefore, power cannot be concentrated in a single representative by gaining more than 1% of the vote. Since there are only 100 representatives, it is conceivable that an attacker could perform a denial of service attack on each representative whose turn it is to produce a block in turn. Fortunately, the threat of this particular attack is easily mitigated due to the fact that each representative is identified by his public key rather than his IP address. This will make it more difficult to identify the target of a DDOS attack. The potential direct connection between representatives will make it more difficult to prevent them from producing blocks.
Advantages: Significantly reduces the number of nodes participating in verification and accounting, and can achieve second-level consensus verification.
Disadvantages: The entire consensus mechanism still relies on tokens, and many commercial applications do not require the existence of tokens.
3.PBFT: Practical Byzantine Fault Tolerance, Practical Byzantine Fault Tolerance
Introduction: It provides (n-1)/3 fault tolerance on the premise of ensuring liveness & safety.
In distributed computing, different computers try to reach a consensus through message exchange; but sometimes, the coordination computer (Coordinator/Commander) or member computer (Member/Lieutanent) on the system may exchange errors due to system errors. messages, affecting the final system consistency.
The Byzantine Generals Problem looks for possible solutions based on the number of faulty computers. This cannot find an absolute answer, but it can only be used to verify the effectiveness of a mechanism.
The possible solution to the Byzantine problem is:
Consistency is possible in the case of N ≥ 3F + 1. Among them, N is the total number of computers, and F is the total number of problematic computers. After information is exchanged between computers, each computer lists all the information obtained and uses the majority of the results as a solution.
1) The system can operate without the existence of currency. Each node of the pbft algorithm consensus is composed of business participants or supervisors, and security and stability are guaranteed by business stakeholders.
2) The consensus delay is about 2 to 5 seconds, which basically meets the requirements of commercial real-time processing.
3) The consensus efficiency is high and can meet the needs of high-frequency transaction volume.
Disadvantages:
1) When 1/3 or more bookkeepers stop working, the system will be unable to provide services;
2) When 1/3 or more bookkeepers join forces to commit evil , and when all other bookkeepers are divided into two network islands, malicious bookkeepers can cause the system to fork, but will leave cryptographic evidence
Let’s talk about two domestic ones~
4.dBFT: delegated BFT Authorized Byzantine Fault Tolerance Algorithm
Introduction: The dBFT mechanism adopted by Xiaoyi selects bookkeepers based on equity, and then the bookkeepers reach a consensus through the Byzantine Fault Tolerance algorithm.
This algorithm has made the following improvements based on PBFT:
Improved the request response mode of the C/S architecture into a peer-to-peer node mode suitable for P2P networks;
Modified the static consensus participating nodes Improved to a dynamic consensus participating node that can dynamically enter and exit;
A voting mechanism based on the proportion of equity held is designed for the generation of consensus participating nodes, and the consensus participating nodes (accounting nodes) are determined through voting.;
The introduction of digital certificates into the blockchain solves the problem of authenticating the true identity of accounting nodes in voting.
Advantages:
1) Professional bookkeeper;
2) Can tolerate any type of errors;
3) Bookkeeping is completed by multiple people, each block All are final and will not fork;
4) The reliability of the algorithm has strict mathematical proof;
Disadvantages:
1) When 1/3 or more bookkeepers stop working Afterwards, the system will be unable to provide services;
2) When 1/3 or more of the bookkeepers jointly commit evil, and all other bookkeepers are divided into two network islands, the malicious bookkeeper can use The system bifurcates, but cryptographic evidence will be left;
In summary, the core point of the dBFT mechanism is to ensure the finality of the system to the greatest extent, so that the blockchain can be suitable for real financial applications Scenes.
5.POOL verification pool
Based on traditional distributed consistency technology, plus data verification mechanism.
Advantages: It can work without tokens. Based on mature distributed consensus algorithms (Pasox, Raft), it can achieve second-level consensus verification.
Disadvantages: The degree of decentralization is not as good as bictoin; it is more suitable for a multi-center business model with multi-party participation.

2. Briefly discuss the major applications of blockchain and which ones are pitfalls

What can blockchain do? Blockchain, a great technology that accompanied the birth of Bitcoin, is currently being used in the financial field to significantly reduce transaction costs and improve efficiency, which is enough to excite Wall Street. However, this is just the tip of the iceberg. Its potential applications are very broad and will subvert every aspect of our lives in the future.

The Internet is an information network, with 0s and 1s flowing in it. Blockchain is a value network, and its role is to transmit value, unlike the Internet for data transmission.

Speaking of value transfer, there is a very simple scenario, such as payment, I have 100 yuan in hand, and I want to transfer it to the group. I can use WeChat red envelopes or WeChat transfers. Here During the transaction process, a third party is required to participate, and the transmission method of the blockchain is point-to-point transmission, which does not require any intermediate node. This is a very big difference between the blockchain and our existing architecture.

When it comes to peer-to-peer payments, many people will think of Bitcoin, because most people know blockchain from Bitcoin. What is the difference between blockchain and Bitcoin?

Blockchain is the technology behind Bitcoin; blockchain is a basic technical architecture that designs and implements an autonomous system with multi-party participation through a specific data structure and consensus algorithm.

The specific data structure is actually the name blockchain itself, that is, its data is placed piece by piece.Inside the data block, this data block is then connected and implemented using a chain. "Consensus algorithm" is a very important concept in blockchain. Without synchronic algorithm, there would be no meaning of blockchain.

Introduction to Bubi Blockchain

Bubi Blockchain has been focusing on the R&D and innovation of blockchain technology and products since its establishment, and has a number of core technologies. It has made substantial innovations in many aspects and formed a number of core technical achievements, such as: mathematically provable distributed consensus technology, fast large-scale ledger access technology, multi-chain general ledger technology that supports business expansion, and heterogeneous ledger technology. Construct interconnection technology between blockchains, etc. On April 25, "Gege Points" introduced the concept of blockchain into the points system, jointly opened it up with multiple parties, issued and redeemed points, and promoted the circulation of points. Each cooperative institution can jointly participate in transaction verification, ledger storage, and real-time settlement; the third-party payment platform of the enterprise points issuer makes the entry and exit of points more flexible. Bubi has developed its own basic blockchain service platform, which has been applied in equity, supply chain, points, credit and other fields. Bubi has been committed to building an open value circulation network with decentralized trust as the core, allowing digital assets to flow freely.

Having said that, let’s analyze the difference between blockchain and Bitcoin?

1. Essential difference. For the world, Bitcoin is a digital currency based on cryptography, while blockchain, as we just said, is a value transfer protocol. There is an essential difference between the two, because one is a digital currency. , one is a value transfer protocol.

2. Algorithm. Bitcoin's consensus algorithm is based on a working algorithm called proof of work, POW. There are many different consensus algorithms in the blockchain. It can use either the Bitcoin POW algorithm, the POS algorithm, or the DPS algorithm.

3. Transaction speed. Bitcoin is limited to a maximum of seven transactions per second. Please note that what is mentioned here is the maximum and not the average, because this is a very strict definition. For the blockchain, the number of transactions per second can actually reach tens of thousands or more, so this is also One major difference between blockchain and Bitcoin. Because many people will be confused and say that the transaction speed of the blockchain is seven transactions per second. This is wrong. This is a limitation of Bitcoin. The blockchain can reach very high speeds based on its different consensus algorithms and linking methods. Transaction speed.

4. Link form. Bitcoin is a blockchain based on the Internet, which means we call it a public chain. The blockchain can be in the form of a public chain, a private chain, or a consortium chain.

5. Limitations. It is recommended that everyone not touch some digital currencies related to blockchain. What's the reason? As a digital currency like Bitcoin, although it has quite good and different characteristics, it does notIt complies with financial supervision, which means that these 21 million Bitcoins were issued without state authorization and without state credit as a multiple. The blockchain also has some limitations. Although it is just a protocol and a technology, it is still a new technology in its infancy.

To summarize, blockchain is a relatively low-level protocol and a technical infrastructure, on which there are various consensus algorithms. If the blockchain is 1, the consensus algorithm may be 10 to 20, but the applications based on it may be one thousand or two thousand, or more. In other words, Bitcoin is only one of many blockchain applications. A realization. Therefore, Bitcoin and blockchain cannot be equated. Bitcoin is only a very elementary implementation of blockchain.

What can blockchain do? Blockchain problem? In the bill market, digital bills based on blockchain technology can become a safer, smarter, and more convenient bill form. Point-to-point transactions realized with the help of blockchain can break the existing functions of bill intermediaries and realize the disintermediation of bill value transfer; the construction and data storage of digital bill systems do not require a central server, eliminating the need for the development of central applications and access systems. cost, which reduces the maintenance and optimization costs of the system under the traditional model, and reduces the risks caused by system centralization; based on the non-tamperability of information on the blockchain, once the transaction is completed, there will be no default, thereby avoiding "one Behaviors such as "selling too many tickets" and out-of-synchronization of payment and endorsement effectively prevent risks in the bill market. The securities trading market is also an area where blockchain technology has great potential. The current traditional securities trading model has the shortcomings of long transaction processes, low transaction efficiency, and high comprehensive costs. In addition, there are strong intermediaries and regulatory agencies, and the rights of financial consumers are often not protected. Applying blockchain technology, buyers and sellers can be directly matched through smart contracts, and the efficiency of transaction execution can be greatly improved. Settlement and delivery can be automatically realized through a distributed digital registration system. Since the data entered into the block is irreversible and can be copied to each data block within a short period of time, the information entered into the blockchain actually has a publicity effect, so the occurrence of the transaction and the confirmation of ownership will not occur. dispute.

What can blockchain do? Blockchain problem? Although there is no mature underlying blockchain technology platform solution currently, technical problems such as capacity scalability, privacy protection, inability to settle on a net basis, and non-recourse after the event also need to be solved, and large-scale application of blockchain Technology also requires redesigning IT architecture and reengineering business processes, but these are only technical issues. The real test of blockchain technology taking root and growing in the financial field is the ontology of regulatory agencies and financial institutions. Will the inherent "deregulation" and "decentralization" characteristics of blockchain make market entities have no motivation to drive technology? Innovation. However, since blockchain is a technology based on mathematical algorithms, the establishment of a trust relationship between transaction parties does not require the use of intermediaries or authoritative centers to establish trust.The cost of the relationship is almost zero (on the premise that the blockchain financial infrastructure and ancillary infrastructure are established), and the blockchain code is open source and open, with no geographical restrictions, and the network pattern is distributed and interconnected, providing a platform for future inclusive finance and shared finance. Its establishment and development have laid a technical foundation and created material conditions for global financial integration and unification. From this point of view alone, blockchain technology will surely establish a core position in future financial development, and it will rely on and complement each other to win the future.

3. The conversion of Ethereum to PoS will have an impact on mining

If it is completely converted to PoS, mining will be GG, and the generation of new coins will no longer be a competition for contribution to computing power. With the account rights, it has completely become a dividend for holding eth!

4. Is blockchain reliable?

With the development of the times, many science and technologies are now used in people’s lives, and blockchain is used in a very wide range of An Internet technology, the purpose of blockchain is to verify the validity of information, so it has an anti-counterfeiting function. Blockchain is a combination of many data blocks in a chain structure in time order to maintain the reliability of the database. The application fields of blockchain are also relatively wide, and are often used in finance, the Internet, insurance, and some public welfare fields. Blockchain is divided into public and private. Its biggest features are high transparency, decentralization and collective maintenance. Because it is used too widely, many people have doubts about blockchain in daily life. I don’t know. Is it reliable?

Generally speaking, blockchain technology is not a scam. It is reliable, but it also has certain disadvantages. Blockchain technology can have great benefits if applied in legal fields, but once it goes astray and is introduced into illegal fields, it will have very serious consequences.

5. Blockchain consensus mechanism POS and DPOS

As the first consensus mechanism in the blockchain and one that has withstood sufficient practical testing, the workload proof algorithm solves It is a problem of consistency of transaction information in distributed systems. It builds a trust mechanism for nodes that do not trust each other in a decentralized network. It is also a key technical link for the successful application of Bitcoin.

After several years of actual operation, the shortcomings of this algorithm have also been revealed. The Bitcoin network completes 600 trillion SHA256 operations per second, consuming a large amount of power resources. In the end, these calculations have no practical effect. or scientific value. The only purpose of these operations is to solve the proof-of-work problem. Another real threat is the concentration of computing power. Proof-of-work is essentially a process of using exhaustive methods to find hash values ​​that meet specified conditions. The stronger it is, the higher the possibility of obtaining accounting rights (that is, mining). At first, it was the first people to use graphics cards to mine, and later to use FPGA mining machines, and then to use ASIC special chips to mine. People are now the ones who are constantly making better ASICs, and there are also "miner" nodes who join forces to form mining pools, such as Ghash, Ghash issued a statement in 2014 that it would ensure no more than 40% of the computing power of the entire network in the future. Such self-discipline statements are a great irony of Bitcoin’s trustless mechanism.

Since the birth of Bitcoin, people have begun to try other consensus mechanisms besides the proof-of-work algorithm, such as the representative proof-of-stake POS, delegated proof-of-stake DPOS, and Byzantine Fault Tolerance (BFT). and Practical Byzantine Fault Tolerance (PBFT), etc. Below we will mainly introduce POS and DPOS, leaving BFT and PBFT for the next article.

Proof of Stake POS

POS is a type of consensus algorithm, or the design idea of ​​a type of consensus algorithm, not one. The first to adopt POS was Peercoin. Peercoin is a type of cryptocurrency launched by a geek with the pseudonym Sunny King in August 2012. It adopts the proof-of-work mechanism + the proof-of-stake mechanism, and introduces the proof-of-stake mechanism into cryptocurrency for the first time. Peercoin introduces the concept of "coin age". Each coin generates 1 coin age every day. For example, if you hold 100 coins for a total of 30 days, then your coin age will be 3000 at this time. When a new block is generated, other nodes that want to obtain accounting rights also need to calculate the hash value of Bitcoin. The difficulty of obtaining the hash value that meets the conditions is related to the difficulty value. This difficulty value here is related to the age of the currency. Inversely proportional, that is, the older your currency is, the greater the probability of obtaining a hash value that meets the conditions. At the same time, your currency age is cleared, and the system will give you corresponding "interest" after accounting. You will get 365 coins every time it is cleared. Age, the interest earned is: 3000 * interest rate / 365, the interest rate of Peercoin is 1%, which is 0.08 coins.

It can be seen that under the POS mechanism, the more coins you hold, the easier it is to obtain accounting rights, which is close to the winner-takes-all feeling. But the more coins you hold, the closer it is to an honest person. nodes, the greater the loss caused by destroying the entire network. There is a loophole in Peercoin's POS mechanism. For people who do not hold coins, they have little benefit, so some malicious attacks have no loss for them. This is a Nothing-at-stake attack. Subsequent more successful POSs have introduced mechanisms to deal with this kind of attack.

The Ethereum system aims to introduce proof of stake, known as Casper, this year. Under the proof-of-stake consensus mechanism, users will be able to have “currency rights” in the Ethereum network. Users who act honestly and confirm legitimate transactions will receive interest proportional to their equity; users who act maliciously and attempt to cheat the network will lose their equity.

Delegated Proof of Equity DPOS

Delegated Proof of Equity DPOS is a variant of POS. Typical examples of using DPOS are BitShares. The basic principle is that the entire network votes to select 101 nodes.Click on the agent's accounting authority. The authority of these representative nodes is exactly the same. The representative nodes take turns keeping accounts and can choose to create blocks or not. But they cannot change the details of the transaction, and the behavior of malicious or late representative nodes will be made public, and the network may vote them out simply and quickly. Representative nodes that are expelled will lose their accounting rights and corresponding income.

As a weakly centralized consensus mechanism, DPOS retains some key advantages of centralized systems, such as transaction speed (the time of each block is 10 seconds, and a transaction gets 6- It takes about 1 minute after 10 confirmations, and a complete 101 block cycle only takes about 16 minutes), but each currency holder has the ability to decide which nodes can be trusted, and in fact, representative nodes will actively lower their own To win more votes, the remaining income will be paid as dividends to all BitShares holders. DPOS is somewhat similar to representative democracy and the joint-stock company board of directors system. It is an elite system, but its identity is subject to the people below. In DPOS, the holders of the currency at least have the right to decide the identity of the representative node-or miner.

6. What are the security weaknesses of the blockchain?

What are the security weaknesses of the blockchain?

Blockchain is the core technology of Bitcoin. On the Internet that establishes trust relationships, blockchain technology relies on cryptography and clever distributed algorithms without the intervention of any third-party central organization. It uses mathematical methods to enable participants to reach consensus and ensure the existence of transaction records and the validity of contracts. Validity and non-repudiation of identity.

The often mentioned characteristics of blockchain technology are decentralization, consensus mechanism, etc. The virtual digital currency derived from blockchain is currently the most popular in the world. One of the projects is creating a new batch of billionaires. For example, the Binance trading platform, just a few months after its establishment, has been rated by internationally renowned institutions as having a market value of US$40 billion, making it one of the richest digital currency entrepreneurial pioneers. However, since the establishment of digital currency exchanges, there have been endless incidents of exchanges being attacked and funds being stolen, and some digital currency exchanges have suffered heavy losses due to hacker attacks or even gone bankrupt.

1. The shocking attack on digital currency exchanges

From the earliest Bitcoin to the later Litecoin and Ethereum, there are currently hundreds of digital currencies. . As prices rise, attacks on various digital currency systems and digital currency thefts continue to increase, and the amount stolen is also soaring. Let’s review the shocking incidents of digital currencies being attacked and stolen.

On February 24, 2014, Mt. Gox, the world’s largest Bitcoin exchange operator at the time, announced that all 850,000 Bitcoins on its trading platform had been stolen, accounting for more than 80% of all Bitcoins. Exchange Mt.Gox filed for bankruptcy protection due to its inability to cover customer losses.

After analysis, the reason is roughly Mt.Gox has a serious error such as a single point of failure structure, which is used by hackers to launch DDoS attacks:

The signature of the Bitcoin withdrawal link was tampered with by hackers and entered the Bitcoin network before normal requests. As a result The forged request can be withdrawn successfully, but the normal withdrawal request is abnormal and displayed as failed on the trading platform. At this time, the hacker has actually obtained the withdrawn Bitcoin, but he continues to request repeated withdrawals on the Mt.Gox platform. Mt. .Gox repeatedly paid equal amounts of Bitcoins without conducting transaction consistency verification (reconciliation), resulting in the theft of Bitcoins from the trading platform.

On August 4, 2016, Bitfinex, the largest US dollar Bitcoin trading platform, announced that a security vulnerability was discovered on the website, resulting in the theft of nearly 120,000 Bitcoins, with a total value of approximately US$75 million.

On January 26, 2018, the Coincheck system of a large digital currency trading platform in Japan suffered a hacker attack, resulting in the digital currency "New Economic Coin" with a current price of 58 billion yen, approximately US$530 million. This is the largest digital currency theft in history.

On March 7, 2018, the news that Binance, the world’s second largest digital currency exchange, was hacked kept the currency circle awake at night. The hackers actually started playing economics, buying and selling short and “speculating”. "Coins" to cut leeks. According to Binance’s announcement, the hacker’s attack process includes:

1) Using third-party phishing websites to steal users’ account login information over a long period of time. Hackers carried out web phishing attacks on users by using Unicode characters to impersonate some letters in the legitimate Binance website domain name.

2) After the hacker obtains the account, he automatically creates a trading API and then lurks quietly.

3) On March 7, hackers used the stolen API Key to directly increase the value of VIA currency by more than 100 times by using short selling methods. Bitcoin plummeted by 10%, with a total of 17 million bits in the world. According to currency calculations, Bitcoin lost US$17 billion overnight.

2. Why hacker attacks are so successful

The hot market of blockchain-based digital currency has made hackers salivate. The amount of money stolen continues to set new records, and the occurrence of theft incidents also increases. This has raised concerns about the security of digital currencies, and people can’t help but ask: Is blockchain technology safe?

With the research and application of blockchain technology, in addition to the information system to which it belongs, the blockchain system will face threats from viruses, Trojans and other malicious programs and large-scale DDoS attacks. And face unique security challenges.

1. Algorithm implementation security

Since blockchain uses a large number of cryptographic technologies, it is a highly algorithm-intensive project and is prone to problems in implementation. There have been precedents of this kind in history. For example, the NSA embedded flaws in the implementation of the RSA algorithm, allowing it to easily crack other people's encrypted information. Once a vulnerability of this level breaks out,It can be said that the foundation that constitutes the entire blockchain building will no longer be safe, and the consequences will be extremely dire. Bitcoins have been stolen before due to problems with the Bitcoin random number generator. In theory, the private key can be deduced by using the same random number twice during the signing process.

2. Consensus mechanism security

A variety of consensus algorithm mechanisms have appeared in current blockchain technology, the most common ones are PoW, PoS, and DPos. However, whether these consensus mechanisms can achieve and ensure true security requires more rigorous proof and the test of time.

3. The use of blockchain is safe

A major feature of blockchain technology is that it is irreversible and unforgeable, but the premise is that the private key is safe. The private key is generated and kept by the user, and theoretically no third party is involved. Once the private key is lost, no operations can be performed on the account's assets. Once obtained by hackers, digital currencies can be transferred.

4. System design security

Since platforms such as Mt.Gox have single points of failure in business design, their systems are vulnerable to DoS attacks. Currently blockchain is decentralized while exchanges are centralized. In addition to preventing technology theft, centralized exchanges must also manage people well to prevent human theft.

In general, from the perspective of security analysis, blockchain faces challenges in algorithm implementation, consensus mechanism, use and design. At the same time, hackers can also achieve attacks by exploiting system security vulnerabilities and business design flaws. Purpose. Currently, hacker attacks are having an increasing impact on the security of blockchain systems.

3. How to ensure the security of the blockchain

In order to ensure the security of the blockchain system, it is recommended to refer to the NIST network security framework from a strategic level and the network security of an enterprise or organization. From the perspective of the entire life cycle of risk management, five core components of identification, protection, detection, response and recovery are constructed to perceive and block blockchain risks and threats.

In addition, according to the characteristics of blockchain technology, we focus on the security of algorithms, consensus mechanisms, usage and design.

Achieving security for algorithms: On the one hand, choose to adopt new cryptographic technologies that can stand the test, such as the national secret public key algorithm SM2. On the other hand, strict and complete testing of the core algorithm code and source code obfuscation will increase the difficulty and cost of reverse attacks by hackers.

For consensus algorithm security: PoW uses anti-ASIC hash functions and uses more effective consensus algorithms and strategies.

For usage security: protect the generation and storage of private keys, and encrypt and store sensitive data.

For design security: On the one hand, we must ensure that the design functions are as complete as possible, such as using private key white-box signature technology to prevent viruses and Trojans from extracting private keys during system operation; designing a private key leak tracking function , to minimize the loss after the private key is leaked. On the other hand, some key business designs should be decentralized to prevent single points of failure.attack.

7. What are the advantages and disadvantages of the POW and POS consensus mechanisms? Can any expert explain it?

POW: Proof of Work, proof of work. Bitcoin uses this mechanism in the block generation process. Finding a reasonable Block Hash requires a large number of attempts to calculate, and the calculation time depends on the hashing speed of the machine. POS: Proof of Stake, proof of equity. To put it simply, it is a system that pays you interest based on the amount and time you hold the currency. In the POS mode, holding currency has interest. DSC (Dynamic Equity) consensus algorithm: an original creation of the public chain project Penta. It is divided into three layers: the first layer conducts representative elections, the second layer selects members and observers to form several consensus groups through a three-column fundraising algorithm, and the third layer selects official blocks from candidate blocks through a hash lottery algorithm.

8. Honghe Java Training School tells you the consensus algorithm in blockchain technology

We have shared with you many times some explanations and analysis of knowledge points about blockchain technology. . Today, Honghe Java Course http://www.kmbdqn.cn/ will take a look at some basic definitions and characteristics of consensus algorithms in blockchain technology.

A brief look at the blockchain

The chain in our general ideology is an iron chain, made of iron. One link after another. Figuratively, the blockchain can also be understood in this way, except that it is not made of iron, but connected by blocks with a certain data structure. This is a simple prototype

Popular explanation of consensus

The so-called consensus, in layman’s terms, means that we all agree on the understanding of something. For example, we have daily meetings to discuss issues, or we can judge whether an animal is a cat. After looking at it with the naked eye, we feel it looks like a cat. If it meets the characteristics of a cat, then we think it is a cat. Consensus is a rule.

Continuing with our meeting example. Participants in the meeting discuss and solve problems through meetings.

Compared with the blockchain, miners participating in mining use a certain consensus method (algorithm) to make their own ledger consistent with the ledgers of other nodes. The deeper meaning of keeping the ledger consistent is to keep the block information in the chain consistent.

Why is consensus needed? Is it possible to not need it? Of course not. Without the rules of consensus in life, everything will be chaotic. The blockchain loses consensus rules, and each node does its own thing, losing its consistent meaning.

The corresponding relationship between these two examples is as follows:

Meeting people = mining miners

Meeting = consensus method (algorithm)

Talk about the solution in handSolve the problem = make your own ledger consistent with the ledgers of other nodes

If you don’t understand the concept of a node, please first understand it as a miner. A node contains many roles. , miners are one of them.

Consensus algorithm

Currently in the blockchain, nodes allow their own ledgers to match those of other nodes. There are several consensus methods (algorithms) that maintain consistency:

PoW, represented by Bitcoin (BTC)

Disadvantages:

The emergence of mining pools violates the original intention of decentralization to a certain extent, and also makes 51% attacks possible, affecting its security.

There is a huge waste of computing power. Look at the mining pool that consumes a lot of electricity resources. As the difficulty increases, what is mined is not enough to pay the electricity bill

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PoS, represented by Ethereum (ETH), transitioning from PoW to PoS

Disadvantages:

< p>The cost of attackers attacking the network is very low, and they can compete if they own tokens

In addition, nodes with a large number of tokens will have a greater probability of obtaining accounting rights. This will make the network consensus dominated by a few wealthy accounts, thereby losing fairness.

9. What will happen after Ethereum merges/turns to PoS?

What will happen after Ethereum merges/turns to PoS? Today is Ethereum Many people are very concerned about the day when Ethereum merges, and many people also have questions about what will happen after the PoS after the merger of Ethereum. Let’s take a look with the editor. I hope this article can help you.
What will happen after Ethereum merges/moves to PoS
Many debates have arisen before the merger is officially announced, and they will continue to exist long after the merger.
Ethereum’s move to Proof-of-Stake (PoS) can be considered one of the most important events in the crypto industry. Speculation and misinformation are rife. Here we discuss the facts and consequences of this technological experiment.
It should be emphasized that the developers’ decision to switch from the original consensus protocol Proof of Work (PoW) to PoS has been several years in the making. BeaconChain (Beacon Chain) is the fork of the Ethereum blockchain responsible for using PoS and was initially launched on December 1, 2020 for development and testing.
There is no doubt that the shift from PoW to PoS will lead to changes in the perception of Ethereum as a network. There are many perspectives to consider: Economics, Environment, Token Economics, Competition with Other Cryptocurrencies, Legal, Centralization vs. Decentralization Ultimately, the changes that Ethereum’s switch from PoW to PoS will bring to the blockchain and to crypto as a whole A turning point for the community.
Ethereum becomes sustainable, but Bitcoin will stand aloneFlag
Using PoS as a consensus mechanism will lead to a significant reduction in the energy required by the Ethereum blockchain.
Several studies have concluded that due to the merger, Ethereum will reduce electricity consumption by 99.95% after implementing PoS, a fact that cannot be ignored.
The first event after the implementation of PoS will be that Ethereum’s hash rate plummets to zero, representing the end of an era. Any user with ETH can become a validator. They can also earn rewards by staking ETH in the protocol.
The most immediate impact of the merger will be how the media pays more attention to Bitcoin and the environmental damage it causes. Investors who prefer PoW mechanism blockchains are hesitant to invest in Ethereum. For example, Tesla abandoned its original proposal to use Bitcoin as a means of payment due to its carbon footprint.
With PoS, Ethereum provides a clear path for any investor who must follow ESG standards (environmental, social and governance standards), inject funds into ETH, or invest in companies related to Ethereum activities Especially so.
In this way, Bitcoin remains a target for the media, while Ethereum avoids the most controversial issues surrounding cryptocurrencies in recent years.
Regulators will have fewer arguments against Ethereum
It is known that regulators have long wanted to intervene in the crypto market or establish certain ground rules. On the one hand, it seems that due to the small size of the crypto market, they are in no rush to intervene. But on the other hand, they observed that the long-term growth of cryptocurrencies could endanger national currencies.
But due to the versatility among crypto projects, regulating cryptocurrencies is not a simple task. So regulators have to start somewhere, and sustainability issues seem to have been the overarching argument for choosing to regulate cryptocurrencies.
PoW is one of the reasons why cryptocurrencies are unsustainable, so regulators are considering banning it. Some regulators claim that mining cryptocurrencies through PoW should be banned due to its high electricity consumption.
MiCA, the encryption regulatory bill released by the EU, had already included a ban on PoW mining, although it was ultimately delayed. In the United States, the latest report from the White House pointed out that the impact of cryptocurrency and corresponding blockchain technology on greenhouse gas emissions, pollution, and noise remains high, which hinders federal agencies from achieving net-zero carbon pollution consistent with U.S. climate commitments and goals s hard work.
In the report, Ethereum is believed to be responsible for 20-39% of the electricity expenses generated by mining cryptocurrencies, while Bitcoin is estimated to be 60-77%. As Ethereum moves to PoS, regulators will not be able to use this argument to continue opposing the blockchain. This provides a layer of assurance for crypto businesses built on Ethereum.