区块链防篡改是什么意思,区块链防篡改原理

在当今社会，信息安全是一个非常重要的话题。随着区块链技术的发展，信息安全也得到了很大程度的提升。那么，区块链防篡改是什么意思呢？

区块链防篡改，就是在区块链系统中，通过一定的方法，来防止篡改区块链系统中存储的数据以及维护系统的完整性。它是一种分布式的记账方式，它能够有效地防止篡改，保证数据的安全性。

那么，区块链防篡改原理是什么呢？

首先，区块链防篡改原理的核心是分布式记账技术。它是一种基于分布式账本的记账技术，它能够将数据存储在多个节点中，以防止篡改。

其次，区块链防篡改原理的另一个核心是共识机制。它是一种基于去中心化技术的共识机制，它能够有效地防止篡改，保证数据的安全性。

最后，区块链防篡改原理的另一个核心是加密技术。它是一种基于密码学的加密技术，它能够有效地防止篡改，保证数据的安全性。

总的来说，区块链防篡改原理是一种基于分布式账本技术、共识机制和加密技术的一种信息安全技术，它能够有效地防止篡改，保证数据的安全性。

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Ⅰ How is Yibaoquan’s blockchain evidence tamper-proof

1. Yibaoquan blockchain technology

Distinctions of Yibaoquan The blockchain is built based on the BCOS open source platform. It uses the SHA-512 hash algorithm, timestamp service, and PBFT consensus algorithm to calculate metadata and can flexibly expand alliance chain institutions and nodes. The data stored and preserved on the blockchain through Yibaoquan will be stored on the blockchain in the form of hash values. Through the characteristics of blockchain decentralization and distributed storage, the authenticity and objectivity of the data can be effectively guaranteed. Effectively tamper-proof.

2. Yibaoquan blockchain certificate storage

Yibaoquan uses blockchain technology to cooperate with notary offices, judicial appraisal centers, arbitration committees, Internet courts, copyright protection centers, and CAs An open platform for the security chain initiated by institutions and others and open to the outside world. Allow electronic data to be synchronized from generation, storage, to final use to each node of the preservation chain open platform, for synchronous supervision and notarization, and the issuance of relevant certificates and blockchain queries, effectively ensuring the integrity of the data. Judicial effectiveness.

II Blockchain: Tamper-proof Hash Encryption Algorithm

Students A and B tossed a coin in the classroom to bet on who would clean the house. If it's up, A will clean it, and if it's tails up, then B will clean it. There's nothing wrong with this strategy.

However, if the scenario is transferred to an online chat room, and A and B also play a coin-tossing game, B will probably not agree, because when A tosses a coin, B will not guess.

Heads or tails, A can say that B guessed wrong.

How to solve this problem? How about encrypting the result of the coin toss first, and then B guesses? You can try this method.

Assume that any odd number represents the front side of the coin, and any even number represents the tail side. A wants a number 375, then multiplies it by 258, tells B the result is 96750, and declares that the 375 A wants is the key, which he keeps for safekeeping.
When verifying the result next, A can lie and claim that 258 is the number he wants and 375 is the key, and A is still invincible. What if A tells B the key in advance? B can directly calculate the original number, losing the confidentiality function.

This method of knowing the encryption method and knowing the decryption method obviously does not work. Is there a way to know the encryption method and still not be able to recover the original text?

Obviously there is, it is OK to add irreversible operations to the encryption process. A designs a new encryption method:

Assume that the number A wants is 375 and encrypts it:

B gets the result 120943, but he can hardly calculate the key 375 based on 120943.
If B wants to verify whether A is lying:

Finally, he can flip a coin...

This kind of encryption loses part of the informationThe method is called "one-way encryption", also called hash algorithm.

There is a problem:

This is possible, but it can be solved by increasing the difficulty of the above algorithm so that A is difficult to find.

According to the above statement, a reliable hash algorithm should satisfy:

The hash function in cryptography has three important properties, namely collision resistance and irreversibility of the preimage. , problem friendliness.

Collision means that student A can find out an odd and an even number in advance to make the hash results consistent, which is computationally infeasible.

First of all, if the news about the large space sauna is compressed into a small space, there will definitely be a collision. Assume that the length of the hash value is fixed to 256 bits. If the order is 1, 2,...2 256 + 1, these 2 256 + 1 input values, and the hash values ​​are calculated one by one, you will definitely be able to find two input values ​​that make the hash The values ​​are the same.

Student A, when you see this, please don’t be too happy too early. Because you have to have time to figure it out before it's yours. Why do you say that?

According to the birthday paradox, if 2 130 +1 inputs are randomly selected, there is a 99.8% probability of finding at least one pair of collision inputs. Then for a hash function with a hash value length of 256 bits, an average of 2128 hash calculations need to be completed to find the collision pair. If a computer performed 10,000 hash calculations per second, it would take approximately 10 27 years to complete 2 128 hash calculations.

Student A, don’t think about cheating, I guess you won’t live this long. Of course, it is possible if computer computing power is greatly improved.

So what other uses does integrity have?

Used to verify the integrity of the information, because if the information is not tampered with during transmission, the hash value obtained by running the hash calculation will be different from the original hash value.

Therefore, in the blockchain, the collision resistance of the hash function can be used to verify the integrity of blocks and transactions.

Because a hash value corresponds to countless plaintexts, theoretically you don't know which one it is. For example, the results of 4+5=9 and 2+7=9 are the same. I know that the result I entered is 9, but can I know what number I entered?

If, when performing hash calculation on message m, a random prefix r is introduced, and based on the hash value H(r||m), it is difficult to recover message m, which means that the hash function The value hides message m.

Therefore, student B, it is impossible to deduce the original data based on the results. It is like finding a needle in a haystack.

Problem friendliness means that there is no convenient way to generate a hash value that meets special requirements. What does it mean? In layman's terms, there is no shortcut, you need to figure it out step by step. If you ask for the hashThe result starts with several 0s. Then the number of hash calculations required to find a hash value whose first three digits are all 0 and to find a hash value whose first six digits are all 0 is in a certain number.

How can this be used? In the blockchain, it can be used as proof of work in the consensus algorithm.

Mainly describes three important properties of the hash function: collision resistance, preimage irreversibility, and problem friendliness.

Because of these important properties, functions such as integrity verification of blocks and transactions in the blockchain and workload proof of the consensus algorithm are implemented using hash functions.

[1]. Zou Jun, Zhang Haining. Blockchain Technology Guide [M]. Beijing: Mechanical Press, 2016.11
[2]. Chang Chai, Han Feng. Blockchain From digital currency to credit society [M]. Beijing: CITIC Press, 2016.7
[3]. Zhang Jian. Blockchain defines the new future financial and economic landscape [M]. Beijing: Machinery Industry Press, 2016.6

Ⅲ What is blockchain technology and what aspects may it be used for in the future

The essence of blockchain is a point-to-point distributed database that uses a certain consensus algorithm to ensure the integrity of data between nodes. consistency. Bitcoin is a successful application of blockchain technology. The Bitcoin blockchain is currently the most secure blockchain in the world. The data stored in the Bitcoin blockchain is extremely difficult to lose and tamper with. The Bitcoin blockchain generates a new block approximately every 10 minutes. The upper limit of data capacity of each block is 1MB. The Bitcoin network supports a maximum transaction volume of 7 transactions per second.

Blockchain technology is a technology that deeply encrypts and solidifies electronic data. The encrypted and solidified electronic data cannot be tampered with or lost. In addition to the platform's own data center, it is also connected to the forensic identification center and notary office, which enhances the credibility of electronic data and data protection.

Baoquan.com is a one-stop blockchain data security platform. Baoquan.com takes advantage of the characteristics of the underlying architecture of the blockchain in terms of privacy protection, anti-tampering, and anti-attack, and for the first time technically achieves the restoration of the authenticity, uniqueness, and integrity of electronic data. Through in-depth cooperation with judicial appraisal centers and notary offices, Baoquan.com has made blockchain data preservation technology recognized by judicial practice for the first time, opening up the channel between technology and practice.

IV Five Major Characteristics of Blockchain

Blockchain is a term in the field of information technology. In essence, it is a shared database. Five major characteristics of blockchain:

1. Decentralization, that is, all nodes running in the entire blockchain network can perform accounting and have one accounting right. This is completely This avoids one of the drawbacks of centralized operations. It is not a centralization, it is a disintermediation;

2. Openness, this is for the public chain of the blockchainThat’s right, because anyone can read or write the information in the shared chain, as long as they are nodes in the entire network system and have accounting rights;

3. Anti-tampering Anonymity means that anyone who wants to change the information in the blockchain must attack 51% of the nodes in the network to change the data. This is very, very difficult;

4. Anonymity, it The anonymity is based on the fact that its algorithm implements addressing by address, not by personal identity, which is also what the government is worried about. There are two things that are uncontrollable in the entire blockchain. The first is the uncontrollable anonymity of the identity. It is not known who initiated the transaction; the second is that it has a cross-border payment, which involves the transfer of currency funds. One piece;

5. Traceability, its mechanism is to set the next block to have a hash value of the previous block, just like a hook, only the previous hash value is recognized To be able to hang it, it is a complete chain. Another good feature of traceability is that it facilitates data query, because this block has a unique identifier. For example, if you go to the database to query something, there are many algorithms to find it in blocks, and In this blockchain network, time nodes are used to define the block in this time period before addressing it, which is more convenient.

IV How is the security of blockchain? What are the risks of blockchain?

The hottest topic at the beginning of the new year is blockchain, but there are many more. People are skeptical about its security and risks, so how about the security of blockchain? What are the risks of blockchain? Below we will give you the answers one by one. I hope it will be helpful to you after reading them.
How is the security of blockchain Anyuan?
First of all, blockchain is a distributed database technology. Distributed technology mainly refers to storage architecture. The distributed architecture adopted by the blockchain not only stores the ledger data on each node, but also each node must contain the data of the entire ledger. This completely distributed architecture brings extremely high security, and no one can destroy all nodes at the same time.
Secondly, blockchain technology can achieve tamper resistance through "blocks" and "chains". The unit of data storage in the blockchain is the block. When each block is generated, it must contain the unique "characteristic value" of the previous block (which can be regarded as the ID card of the block). Each block is generated strictly according to the The order of time is lined up to form a "chain".
Security is a major feature of blockchain technology. However, from the perspective of privacy protection, the block chain emphasizes openness and transparency, and any node has the right to operate according to the consensus algorithm, so it is not suitable for scenarios where data privacy needs to be protected.
What are the risks of blockchain?
1. Technical risk: For example, the launch of Ethereum was once popular, but because it is a digital currency with smart contracts, it brings the risk of hacker attacks due to possible loopholes in smart contracts. THE largest crowdfunding project in EthereumThe DAO was hacked and lost more than $60 million.
2. Legal risks: The legality issues of digital currency issuance, notarization and confirmation of rights, and legality issues of evidence, including legality issues of smart contracts, digital bills, accounting and liquidation, and equity crowdfunding, are currently in my country and The rest of the world is still legally blank.
3. Crime risks: Using digital currencies to abscond with the money, using digital currencies to launder money and illegal gambling, using smart contracts and digital bills designed to defraud profits, using blockchain technology to commit anonymous crimes, etc. Due to the current regulatory gap, there may be huge criminal risks.
The above is what the editor brings to you. How about the security of blockchain? What are the risks of blockchain? of the entire content.

VI The understanding of “blockchain” and the application of “blockchain”

The understanding of “blockchain” and the application of “blockchain”
“ "Blockchain" can be said to be the hottest keyword right now. Whether it is online information or daily chat, you can hear about it everywhere. Although there is a lot of discussion, most people are still relatively ignorant about "blockchain". Therefore, we often hear many people ask "What is blockchain technology?" "What is the relationship between digital currency and blockchain?" "How can we identify a good blockchain project?" and other related questions.

As for what exactly is blockchain?
Blockchain technology refers to a way for all people to participate in accounting. There is a database behind all systems. You can think of the database as a big ledger. Currently, each system keeps its own account.
But now in the blockchain system, everyone can keep accounts. The system will automatically select the person with the best and fastest accounting, write the contents of his accounting into the ledger, and record the information in the ledger. The content is distributed to everyone in the system for backup.
So what are the benefits of such universal accounting?
First of all, the biggest benefit is security. With this central ledger, others cannot change or destroy it, because it is not a computer Computer control can not only greatly reduce costs, but also improve efficiency. And since everyone has the same ledger, it can ensure that the ledger recording process is open and transparent.
Secondly, the most important thing about blockchain technology is that it can solve the problem of intermediary credit. In the past, it was difficult for two people who did not trust each other to cooperate and had to rely on a third party, just like transfers must go through a bank, but through Blockchain technology, Bitcoin, without the participation of any intermediary agency, has for the first time achieved a transfer behavior in which both parties can trust each other;
Because the blockchain does not require the participation of an intermediary, the process is efficient and transparent, and the cost is very low, Data is highly secure, so any industry or field that has needs in any of these three aspects will have the opportunity to use blockchain technology.

If you still say that "blockchain" can only be used for currency speculation, then you are too behind:
Improvement of living standards, the consumption era has upgraded. Many people like to buy when traveling abroad. Even people who do not go abroad also like to buy some imported goods online. As a result, cross-border online shopping has risen rapidly in recent years. However, many processes and links of cross-border online shopping occur abroad. As a cross-border online shopping user, how can you ensure that the goods you buy are not A-grade or counterfeit goods?
In order to solve the problem of allowing consumers to buy their favorite goods At the same time, it is genuine and licensed. Now we have a reliable and convenient solution, which is blockchain technology. It has the following characteristics:
1. Use block chain data structure to verify and store data.
2. Use distributed node consensus algorithm to generate and update data
3. Use cryptography to ensure the security of data transmission and access
4. Use smart contracts composed of automated script codes to program and manipulate data
Nowadays, many e-commerce companies have taken a fancy to these advantages of blockchain technology and use it for overseas purchase business, such as JD.com. It is understood that JD.com has now reached cooperation with brands such as Kelaisi Mask, Cheonggwanjang Korean Ginseng and Red Ginseng, Amore Cosmetics, Oberton Apricot Dried Raisin Fruit Oatmeal and other brands. With the help of blockchain technology, the products of these brands Information on the raw material process, production process, circulation process, and marketing process is integrated and written into the blockchain to achieve full-process authenticity traceability down to one item and one code.
Thus, each piece of information has its own unique blockchain ID "identity card", and each piece of information is accompanied by the digital signature and timestamp of each subject for consumers to query and verify. The data signature and encryption technology of blockchain enables full-link information to achieve tamper-proof, unified standards and efficient exchange.
Now that we have reliable technology like blockchain, and reliable cross-border traceability and cross-border logistics, we no longer need to go abroad to buy in person, nor do we need to worry about what we are doing on e-commerce platforms. The product purchased is not genuine. As long as we sit at home and move the mouse, our favorite overseas big-name products will arrive as scheduled. I believe that in the near future, blockchain technology will also be applied to other e-commerce companies.

VII Blockchain Technology

Background: After the birth of Bitcoin, it was discovered that the technology was very advanced, and blockchain technology was discovered. Bitcoin and blockchain technology were discovered at the same time.

1.1 The purpose of the birth of Bitcoin:

①Currency transactions have records, that is, ledgers;

②The disadvantages of centralized institution accounting - it can be tampered with; Yi Chaofa

Bitcoin solves the first problem: anti-tampering - hash function

1.2 hash function (encryption method)

① Function: convert any A string of length, converted to a fixed-length (sha256) output. The output is also called a hash value.

② Features: It is difficult to find two different xand y, such that h(x)=h(y).

③Application: md5 file encryption

1.3 Blockchain

①Definition

Block: Split the general ledger into zones Block storage

Blockchain: On each block, add a block header. It records the hash value of the parent block. By storing the hash value of the parent block in each block, all blocks are connected in order to form a blockchain.

②How does the blockchain prevent transaction records from being tampered with?

After the blockchain is formed, tampering with any transaction will cause the hash value of the transaction block to be different from that of its sub-blocks. , tampering was discovered.

Even if you continue to tamper with the hash value in the sub-block header, the hash value in the sub-block will be different from that in the grandchild block, and the tampering will be discovered.

1.4 The essence of blockchain

①The essence of Bitcoin and blockchain: a big ledger visible to everyone, only recording transactions .

②Core technology: Through cryptographic hash function + data structure, it ensures that the ledger records cannot be tampered with.

③Core function: Create trust. Fiat currency relies on government credibility, and Bitcoin relies on technology.

1.5 How to trade

① To conduct transactions, you need an account number and password, corresponding to the public key and private key

Private key: a string of 256-bit binary numbers , no application is required to obtain it, and you don’t even need a computer. You can generate the private key by tossing a coin 256 times.

The address is converted from the private key. The address cannot reverse the private key.

The address is the identity, which represents the ID in the Bitcoin world.

After an address is generated, it can only be known by everyone if it enters the blockchain ledger.

②Digital signature technology

Signature function sign (Zhang San’s private key, transfer information: Zhang San transfers 10 yuan to Li Si) = signature of this transfer

< p> Verify Korean verify (Zhang San’s address, transfer information: Zhang San transfers 10 yuan to Li Si, signature of this transfer) = True

Zhang San uses his own signature function sign() The private key signs this transaction.

Anyone can verify whether the signature was issued by Zhang San himself who holds Zhang San's private key by verifying the Korean vertify(). It returns true, otherwise it returns false.

sign() and verify() are cryptographically guaranteed not to be cracked. ·

③ Complete the transaction

Zhang San will make the transfer information and signature available to the entire network. Under the premise that the account has a balance, after verifying that the signature is true, it will be recorded in the blockchain ledger. Once recorded, Zhang San's account will be reduced by 10 yuan, and Li Si's account will be increased by 10 yuan.

Supports one-to-one, one-to-many, many-to-one, and many-to-many transactions.

In the Bitcoin world, private keys are everything! ! !

1.6 Centralized Accounting

① Advantages of Centralized Accounting:

a. No matter which center keeps accounts, don’t worry too much

< p> b. Centralized accounting, high efficiency

②Disadvantages of centralized accounting:

a Denial of service attack

b Stop service after getting tired

p>

c Central institutions are vulnerable to attacks. For example, destroying servers and networks, committing self-intrusion, legal termination, government intervention, etc.

All attempts at confidential currencies with centralized institutions in history have failed.

Bitcoin solves the second problem: how to decentralize

1.7 Decentralized accounting

①Decentralization: Everyone can keep accounts. Everyone can keep a complete ledger.

Anyone can download open source programs, participate in the P2P network, monitor transactions sent around the world, become an accounting node, and participate in accounting.

② Decentralized accounting process

After someone initiates a transaction, it is broadcast to the entire network.

Each accounting node continues to monitor and continue transactions across the entire network. When a new transaction is received and the accuracy is verified, it is put into the transaction pool and continues to be propagated to other nodes.

Due to network propagation, the transactions of different accounting nodes at the same time are not necessarily the same.

Every 10 minutes, one person is selected from all accounting nodes in a certain way, and his transaction pool is used as the next block and broadcast to the entire network.

Other nodes delete the transactions that have been recorded in their own transaction pool based on the transactions in the latest block, continue accounting, and wait for the next selection.

③ Features of decentralized accounting

A block is generated every 10 minutes, but not all transactions within these 10 minutes can be recorded.

The accounting node that obtains the accounting rights will be rewarded with 50 Bitcoins. After every 210,000 blocks (approximately 4 years), the reward is halved. The total amount is about 21 million, and it is expected to be mined in 2040..

Recording the reward of a block is also the only way to issue Bitcoin.

④ How to allocate accounting rights: POW (proof of work) method

Compete for accounting rights by calculating mathematical problems on several accounting points.

Find a random number that makes the following inequality true:

There is no other solution except traversing the random numbers starting from 0 and trying your luck. The process of solving the problem is also called mining.

Whoever solves the problem correctly first will get the accounting rights.

If a certain accounting node finds the solution first, it will announce it to the entire network. After other nodes verify that it is correct, a new round of calculation will start again after the new block. This method is called POW.

⑤ Difficulty adjustment

The generation time of each block is not exactly 10 minutes

As Bitcoin develops, the computing power of the entire network does not increase.

In order to cope with changes in computing power, the difficulty will be increased or decreased every 2016 blocks (about 2 weeks), so that the average time for each block to be generated is 10 minutes.

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