广东省教师公需课区块链答案2020,广东2020公需课区块链接

Ⅰ Summary of Lesson 4 Cryptography Learning in Blockchain

This is the fourth lesson of deep learning in Ulord. Dr. Yang will give a lecture on the cryptography in blockchain. Regarding cryptography issues, this course helped me understand a question about public keys and private keys that has been bothering me. What is the relationship between them? I got the answer in this study, and now I will share with you what I learned.

The public key and private key in the blockchain are two basic concepts in asymmetric encryption.

Public key and private key are a key pair obtained through an algorithm. The public key is the public part of the key pair, and the private key is the non-public part. Public keys are usually used to encrypt conversations, that is, messages or information, and can also be used to verify digital signatures signed with private keys.

The private key can be used to sign and the corresponding public key can be used for verification. The key pair obtained through this public key system can be guaranteed to be unique worldwide. When using this key pair, if you use one of the keys to encrypt data, you must use its corresponding other key to decrypt it.

For example, data encrypted with a public key must be decrypted with a private key. If a private key is used for encryption, the corresponding public key must be used to decrypt it, otherwise the decryption cannot be successful. In addition, in the Bitcoin blockchain, the public key is calculated through the private key, and the address is calculated through the public key, and this process is irreversible.

Ⅱ Continuing Education: The most fundamental feature of the blockchain network

The most fundamental feature of the blockchain network is the blockchain. Its core idea is decentralization, and the blockchain is the largest The subversion lies in the establishment of credit, and the collective maintenance of the blockchain can reduce costs. Public Blockchain Network A public blockchain is a blockchain that anyone can join and participate in, such as Bitcoin. Disadvantages may include the large amount of computing power required, little or no privacy for transactions, and weak security.
1. Blockchain is a serial transaction record that uses cryptography to connect and protect content. It is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. As an important concept of Bitcoin, blockchain is essentially a decentralized database. As the underlying technology of Bitcoin, it is a series of data generated using cryptographic methods.

Ⅲ Where can I find the answers to Xindao Cloud Blockchain Training Platform

Xindao Cloud WeChat public account. According to relevant information, Xindao Cloud Blockchain Training Platform is a Chinese practical teaching cloud platform that mainly teaches users modern blockchain and Internet knowledge. The answer to Xindao Cloud’s blockchain training platform is that it can be used in Xindao Cloud. If the cloud WeChat official account is found, as long as the user follows the official account and sends a question, the answer and analysis of the question will be displayed.

Ⅳ What exactly is Bitcoin mining calculating and manually verifying the blockchain?Give the answer

Briefly review the mining process.

First, all transactions must be verified and problematic ones eliminated, and then a set of custom criteria are used to select which transactions are to be included in the block, such as the transaction fee provided and the amount occupied by the transaction. Such transactions are considered profitable only if the ratio of byte sizes exceeds a certain threshold. Of course, nodes can also deliberately choose to include a certain transaction, or deliberately ignore certain transactions. If you mine through a mining pool, the mining pool's server will screen the transactions and then assign an independent task to each participating mining machine.

Once the transaction data is filtered and reduced layer by layer, a Merkle tree can be calculated through these transactions, and a unique summary can be determined, which is the root of the Merkl tree.

Then we obtain other information needed for mining in turn, which forms the header of a block.

Byte allocation of block header

The block header is only 80 bytes, and mining only needs to operate on the block header. The transaction data is fixed through the merkle tree and does not need to be included.

Much of this information is already fixed or computable.

Let’s take block 277316 as an example. The information comes from the website http://blockchain.info

Bitcoin Block #277316blockchain.info

Select this block The reason is that in the book "Mastering Bitcoin", the Chinese community translation and the English original version are different in introducing this part of the content, and the author Antonopoulos did not mention a key point, which is the issue of byte order. I believe many people may Step on this trap. The details restored here can help readers and books make cross-references.

Please pay attention to each step below and every change. This is the core algorithm of Bitcoin.

When converting time, remember that it must be converted to UTC timestamp. There have been pitfalls here, so be careful.

The discovery of this step is extremely difficult and consumes a lot of inquiries. Big pits, big pits, please bear in mind. The inventor Satoshi Nakamoto may have changed to a coding method that is closer to the machine in order to make the machine calculate faster.

The final result is

1In hexadecimal, the first 15 0s are followed by 1; and the number corresponding to the difficulty target is

In hexadecimal, the first 15 0s are followed by 3. The calculation result is less than the difficulty target and meets the requirements. This result is consistent with the figures published on the website.

When mining, the nonce random number is unknown and has to be tried from 0 to 2^32. However, this number is actually not big, only 4294967296. With the current mining machine, the computing power is 14T per second. , it doesn’t take even one second to calculate everything up to the upper limit. As mentioned just now, in this case, the incidental information in the currency creation transaction needs to be used, and the additional string becomes the extra nonce.

In addition, the genesis block can also be verified through the above method. Friends who are curious can try it.

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