区块链课程答题技巧,区块链课程答题软件

❶ Are there any better blockchain question-answering apps?

You can download the "Biting" APP, a live-streaming software for answering questions. They will share 12 questions every day. , the questions inside are all about blockchain-related knowledge. A must for beginners! I am also studying, please come together~

❷ 1. Short answer question What are the conditions required for mining in blockchain technology

Mining in blockchain technology What conditions are required for work? 1) An Antminer S9. 2) A power supply, it is recommended to have an official power supply (Ant official power supply). 3) Power cord. 4) A computer: used to register a mining pool account, log in to the mining machine backend, and configure the mining address and miner name. 5) Router. 6) Network cable, etc. 7) Register a mining pool account. 8) Wallet/exchange address: Register a wallet or exchange account, obtain the address of the currency to be mined, and fill it in to the mining pool. If you do not fill in the address, the proceeds will be temporarily stored in the mining pool

❸ What are some important elements of blockchain technology

1. The so-called blockchain technology, referred to as BT (Blockchain technology) , also known as distributed ledger technology, is an Internet database technology that is characterized by decentralization, openness and transparency, allowing everyone to participate in database records.
2. Blockchain is an innovative application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm in the Internet era. In recent years, the development and application of blockchain have had a profound impact on technology. Innovation and industrial revolution are of great significance. This experience introduces relevant knowledge of blockchain technology.
3. Blockchain is a distributed ledger that can contain financial and/or non-financial transactions, replicated (distributed) across multiple systems in near real-time through a peer-to-peer network, and each participant "owns" the same Having a copy of the ledger and getting updates as any transactions are added, each participant helps determine the inherent "immutability" of all existing records, using cryptography and digital signatures to prove identity, authenticity and enforce read/ With write access, there are mechanisms that make it difficult to change the history and can easily detect someone trying to change it.

❹ How to ensure the security of using blockchain

Blockchain itself solves the problem of large-scale collaboration between strangers, that is, strangers do not need to trust each other. You can collaborate with each other. So how to ensure trust between strangers to achieve each other's consensus mechanism? The centralized system uses credible third-party endorsements, such as banks. Banks are regarded as reliable and trustworthy institutions by ordinary people. People can trust banks and let banks resolve real-life disputes. But how does a decentralized blockchain ensure trust?
In fact, blockchain uses the basic principles of modern cryptography to ensure its security mechanism. The knowledge system involved in the field of cryptography and security is very complicated. I will only introduce the cryptography related to the blockchain here.Basic knowledge of cryptography, including Hash algorithm, encryption algorithm, information digest and digital signature, zero-knowledge proof, quantum cryptography, etc. You can use this lesson to understand how the blockchain using cryptography technology can ensure its confidentiality, integrity, authentication and non-repudiation.
Lesson 7 of the basic course: Basic knowledge of blockchain security
1. Hash algorithm (Hash algorithm)
Hash function (Hash), also known as hash function. Hash function: Hash (original information) = digest information. The hash function can map a binary plaintext string of any length into a shorter (usually fixed-length) binary string (Hash value).
A good hash algorithm has the following 4 characteristics:
1. One-to-one correspondence: The same plaintext input and hash algorithm can always get the same summary information output.
2. Input sensitivity: Even if there is any slight change in the plain text input, the newly generated summary information will change greatly, which is hugely different from the original output.
3. Easy to verify: both the plaintext input and the hash algorithm are public, and anyone can calculate by themselves whether the output hash value is correct.
4. Irreversible: If there is only the output hash value, it is absolutely impossible to deduce the plaintext from the hash algorithm.
5. Conflict avoidance: It is difficult to find two plaintexts with different contents, but their hash values ​​are consistent (collision occurs).
Example:
Hash (Zhang San lent Li Si 100,000, with a loan period of 6 months) = 123456789012
A record of 123456789012 is recorded in the ledger.
It can be seen that the hash function has 4 functions:
Simplifying information
It is easy to understand, and the hashed information becomes shorter.
Identification information
You can use 123456789012 to identify the original information, and the summary information is also called the id of the original information.
Concealed information
The ledger contains a record such as 123456789012, and the original information is concealed.
Verification information
If Li Si deceives when repaying the loan, Zhang San only lent Li Si 50,000, both parties can use the hash value and the previously recorded hash value 123456789012 to verify the original information
Hash (Zhang San lent Li Si 50,000, with a loan period of 6 months) = 987654321098
987654321098 is completely different from 123456789012, which proves that Li Si lied, successfully ensuring that the information cannot be tampered with .
Common Hash algorithms include MD4, MD5, and SHA series algorithms. Nowadays, the SHA series algorithms are basically used in mainstream fields. SHA (Secure Hash Algorithm) is not an algorithm, but a set of hash algorithms. Initially it wasSHA-1 series, the current mainstream applications are SHA-224, SHA-256, SHA-384, and SHA-512 algorithms (commonly known as SHA-2). Recently, SHA-3 related algorithms have also been proposed, such as KECCAK used by Ethereum. -256 belongs to this algorithm.
MD5 is a very classic Hash algorithm, but unfortunately both it and the SHA-1 algorithm have been cracked, and are considered by the industry to be not secure enough to be used in commercial scenarios. It is generally recommended to use at least SHA2-256 or higher. Safe algorithm.
Hash algorithms are widely used in blockchains. For example, in a block, the next block will contain the hash value of the previous block, and the content of the next block + the hash value of the previous block The hash values ​​are used together to calculate the hash value of the next block, ensuring the continuity and non-tamperability of the chain.
2. Encryption and decryption algorithms
Encryption and decryption algorithms are the core technology of cryptography. They can be divided into two basic types in terms of design concepts: symmetric encryption algorithms and asymmetric encryption algorithms. They are distinguished according to whether the keys used in the encryption and decryption processes are the same. The two modes are suitable for different needs and form a complementary relationship. Sometimes they can also be used in combination to form a hybrid encryption mechanism.
Symmetric encryption algorithm (symmetric cryptography, also known as public key encryption, common-key cryptography) uses the same encryption and decryption keys. Its advantages are high computational efficiency and high encryption strength; its disadvantage is that it needs to be advanced in advance. Shared key, easy to leak and lose the key. Common algorithms include DES, 3DES, AES, etc.
Asymmetric encryption algorithm (asymmetric cryptography, also known as public-key cryptography) is different from the encryption and decryption keys. Its advantage is that it does not need to share the key in advance; its disadvantage is that the calculation efficiency is low. Only short content can be encrypted. Common algorithms include RSA, SM2, ElGamal and elliptic curve series algorithms. Symmetric encryption algorithm is suitable for the encryption and decryption process of large amounts of data; it cannot be used in signature scenarios: and the key often needs to be distributed in advance. Asymmetric encryption algorithms are generally suitable for signature scenarios or key negotiation, but are not suitable for encryption and decryption of large amounts of data.
3. Information Digest and Digital Signature
As the name suggests, information digest is to perform a Hash operation on the information content to obtain a unique summary value to replace the original complete information content. Information summary is the most important use of the Hash algorithm. Utilizing the anti-collision characteristics of the Hash function, information summary can solve the problem that the content has not been tampered with.
Digital signatures are similar to signing on paper contracts to confirm contract content and prove identity. Digital signatures are based on asymmetric encryption and can be used to prove the integrity of a certain digital content and at the same time confirm the source (or non-repudiation) .
MeWe have two property requirements for digital signatures that make them consistent with what we expect from handwritten signatures. First, only you can make your signature, but anyone who sees it can verify its validity; second, we want the signature to be relevant only to a specific file and not to other files. These can all be used to achieve digital signatures through our asymmetric encryption algorithm above.
In practice, we generally sign the hash value of the information rather than the information itself. This is determined by the efficiency of the asymmetric encryption algorithm. Corresponding to the blockchain, the hash pointer is signed. If this method is used, the previous one is the entire structure, not just the hash pointer itself.
4. Zero Knowledge proof
Zero knowledge proof means that the prover makes the verifier believe that a certain assertion is correct without providing any additional information to the verifier.
Zero-knowledge proofs generally meet three conditions:
1. Completeness: a true proof can allow the verifier to successfully verify;
2. Reliability (Soundness): a false proof It is impossible for the verifier to pass the verification;
3. Zero-Knowledge: If it is proved, no information other than the proof information can be learned from the proof process.
5. Quantum cryptography
As the research on quantum computing and quantum communication receives more and more attention, quantum cryptography will have a huge impact on cryptographic information security in the future.
The core principle of quantum computing is to use qubits to be in multiple coherent superposition states at the same time. In theory, a large amount of information can be expressed through a small number of qubits and processed at the same time, greatly increasing the calculation speed.
In this case, a large number of current encryption algorithms are theoretically unreliable and can be cracked, which makes the encryption algorithms have to be upgraded, otherwise they will be broken by quantum computing.
As we all know, quantum computing is still in the theoretical stage and is still far away from large-scale commercial use. However, the new generation of encryption algorithms must take into account the possibility of this situation.

❺ [Blockchain Course] 3.1—The Concept and Characteristics of Digital Wallet

1. The Concept of Wallet

The traditional wallet in life is equivalent to a A container can be used to store cash, but for digital currency wallets, it is not used to store digital currency, but a management container used to store and manage (including private keys and public keys). The digital wallet has an address (similar to (based on your bank card account number), private key (similar to your bank card password).

Private key: The user uses the private key to sign the transaction, thereby proving that he has the output right of the transaction, and his transaction information does notInstead of being stored within that wallet, it's stored in the blockchain.

Public key: used to generate addresses and store transactions. Information is generated by the private key through an asymmetric encryption algorithm.

Wallet address: It is a 42-digit hexadecimal hash value string starting with a double letter (representing the currency). The address of ETH is a 42-digit hexadecimal hash value string starting with 0x. For example: If a wallet is compared to a bank card, then the wallet address is the bank card number.

The relationship between the three is simply: the private key generates the public key, and the public key generates the address. In short, the address is your account, bank card number, and the private key is your account password. So if someone steals your private key, they will definitely have ownership of your account.

2. Characteristics of wallet

Analogy to a bank card, the private key is like our bank card password + bank card account number, and the digital currency address generated based on the public key is like Our bank card account number is used as the transfer address for transactions. Digital currency is stored in the trading market. The bank card of the wallet keeps our address and password information, giving us control over the digital currency corresponding to the address.

3. The value of wallet to blockchain

Encrypted digital currency is a digital currency based on blockchain technology. Digital currency wallets are specially used to manage these Application of assets. The wallet application creates one or more wallet addresses based on cryptographic principles, and each wallet address corresponds to a key pair: a private key and a public key.

The public key is generated by performing certain mathematical operations based on the private key, and corresponds to the private key one-to-one. The public key is mainly used for external transactions. Each transaction must use the private key to sign the transaction record to prove control over the assets in the relevant wallet address.

The private key is the only certificate that can prove control over digital assets. For digital asset wallets, the private key is the most important. The way the private key is generated and stored determines whether the asset is safe or not.

So the purpose of the wallet is to store the private key. As long as you have the private key, it means you have the corresponding token.

However, the current digital currency market has problems such as inconvenient digital management, high transaction and exchange thresholds, insufficient blockchain performance and unreasonable design, high blockchain development costs, difficulty in connecting to reality, and lack of application scenarios. And other issues. To put it simply, tokens developed based on different public chains require their own wallets, so our mobile phones are filled with apps for multiple wallets.

4. Keywords of digital wallet:

1. Wallet name:

Digital goodsThe wallet name of the currency wallet is the account name or nickname when you created the wallet. Each wallet address corresponds to an account name, because usually digital wallets can create multiple wallet addresses. In order to facilitate identification and management, set one for each wallet address. The name is still necessary.

2. Password:

When you create a digital currency wallet account, you need to set a password. When you transfer and pay, you need to use this password to confirm; Password confirmation is also required when backing up and exporting the private key or keystore; in addition, if you use keystore to import the wallet, you also need password confirmation, and you can reset the password when importing using the private key.

3. Mnemonic phrase:

When you create a wallet, you will be asked to record a string of mnemonic phrases, usually consisting of multiple (12, 15, 18 , 21 digits) composed of irregular English words without any rules, equivalent to the password of your digital wallet + payment password. You will be prompted to save the mnemonic phrase when creating a wallet. Please be sure to save it. It is recommended to record it in a separate notebook with a pen and keep your notebook.

4. Keystore:

The keystore is a file (json) where the wallet stores the private key. The wallet password is required when using this file. When you choose to export or import keystore, you need to enter a password. This password is the password you originally set for this wallet. This is different from using a private key or mnemonic phrase to import a wallet. Using a private key or mnemonic phrase to import a wallet does not require If you know the original password, you can reset it directly.

❻ Briefly describe the role of blockchain technology in the development of modern agriculture

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1. The combination of the Internet of Things and blockchain will enable the agricultural Internet of Things to achieve self-management and maintenance
2. Technology represented by blockchain has requirements that the data be authentic, valid, non-falsifiable, and cannot be tampered with. Compared with the current agricultural big data, it is a new starting point.
3. Applied to agricultural product quality and safety traceability, agricultural product traceability system based on blockchain technology. Once all data is recorded on the blockchain ledger, it cannot be altered. It relies on advanced technology of asymmetric encryption and mathematical algorithms to The human factor is fundamentally eliminated, making information more transparent.
4. Farmers' loans are generally difficult, mainly due to the lack of effective collateral. In the final analysis, it is the lack of a credit mortgage mechanism. The public and non-tamperable attributes of blockchain technology provide the possibility for a decentralized trust mechanism.
5. Blockchain technology can be applied to agricultural industry supply chain [Answer]