Blockchain account password

1.

blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum

blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies

blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block

extended data

according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:

1. The blockchain with the whole network open and without user authorization mechanism is called public chain

2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain

3. All the nodes in the network are in the hands of one organization, which is called private chain

alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain

blockchain features

1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain

2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent

3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention

4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes

5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously

2.

The strict definition of blockchain refers to the distributed database technology that multiple nodes in peer-to-peer network jointly maintain a continuously growing list ledger constructed by time stamp and orderly record data blocks through consensus mechanism based on cryptography technology. This technical solution allows any number of nodes in the participating system to calculate and record all the information exchange data in the system in a period of time to a data block through cryptography algorithm, and generate the fingerprint of the data block for linking the next data block and checking. All participating nodes in the system jointly determine whether the record is true

blockchain is a technical solution similar to NoSQL (non relational database). It is not a specific technology, and can be implemented through many programming languages and architectures. There are many ways to realize blockchain, including pow (proof of work), POS (proof of stake), dpos (delegate proof of stake), etc

the concept of blockchain was first proposed in the paper "bitcoin: a peer-to-peer electronic cash system" by indivials (or groups) who call themselves Satoshi Nakamoto. Therefore, bitcoin can be regarded as the first application of blockchain in the field of financial payment

< H2 > [popular explanation]

no matter how big the system or how small the website is, there is a database behind it. So who will maintain this database? In general, who is responsible for the operation of the network or system, then who is responsible for the maintenance. If it is wechat database, it must be maintained by Tencent team, and Taobao database is maintained by Alibaba team. We must think that this way is natural, but blockchain technology is not

if we think of the database as a book, for example, Alipay is a typical account book. Any change of data is bookkeeping. We can think of database maintenance as a very simple way of accounting. In the world of blockchain, everyone in the blockchain system has the opportunity to participate in bookkeeping. The system will select the fastest and best bookkeeper in a period of time, maybe within ten seconds or ten minutes. The bookkeeper will record the changes of the database and the account book in a block. We can think of this block as a page. After the system confirms that the records are correct, the system will record the changes of the database and the account book in a block, It will link the fingerprint of the past account book to this paper, and then send this paper to everyone else in the whole system. Then, over and over again, the system will look for the next person with fast and good bookkeeping, and everyone else in the system will get a of the whole ledger. This means that everyone as like as two peas in the system is called Blockchain. It is also called distributed account technology. P>

as like as two peas (computer) have identical accounting books, and everyone has the same rights, they will not collapse e to the loss of contact or downtime of a single person. As like as two peas, the data is transparent and everyone can see what changes are in every account. Its very interesting feature is that the data can't be tampered with. Because the system will automatically compare, it will think that the same number of books with the largest number are real books, and a small number of books with different numbers are false books. In this case, it's meaningless for anyone to tamper with his own account book, because unless you can tamper with most nodes in the whole system. If there are only five or ten nodes in the whole system, it may be easy to do so. However, if there are tens of thousands or even hundreds of thousands of nodes and they are distributed in any corner of the Internet, unless someone can control most computers in the world, it is unlikely to tamper with such a large block chain

< H2 > [elements]

combined with the definition of blockchain, we think that we must have the following four elements to be called public blockchain technology. If we only have the first three elements, we will consider it as private blockchain Technology (private chain)

1, peer-to-peer network (power equivalence, physical point-to-point connection)

2, verifiable data structure (verifiable PKC system, non tampering database)

3, distributed consensus mechanism (Solving Byzantine general problem, solving double payment)

4 Game design of Nash equilibrium (cooperation is the strategy of evolutionary stability)

< H2 > [Characteristics]

combined with the definition of blockchain, blockchain will realize four main characteristics: decentralized, trustless, collective maintenance and reliable database. And the other two will be derived from the four characteristics  Features: open source  Privacy. If a system does not have these characteristics, it can not be regarded as an application based on blockchain technology

Decentralized: there is no centralized hardware or management organization in the whole network. The rights and obligations of any node are equal, and the damage or loss of any node will not affect the operation of the whole system. Therefore, it can also be considered that the blockchain system has excellent robustness

trustworthiness: there is no need to trust each other when participating in the data exchange between each node in the whole system. The operation rules of the whole system are open and transparent, and all data contents are also open. Therefore, within the specified rule range and time range of the system, nodes cannot and cannot cheat other nodes

collective maintenance: the data blocks in the system are maintained by all the nodes with maintenance function in the whole system, and these nodes with maintenance function can be participated by anyone

reliable database: the whole system will enable each participating node to obtain a of the complete database in the form of sub databases. Unless more than 51% of the nodes in the whole system can be controlled at the same time, the modification of the database on a single node is invalid, and the data content on other nodes cannot be affected. Therefore, the more nodes and computing power in the system, the higher the data security in the system

Open Source: since the operation rules of the whole system must be open and transparent, the whole system must be open source for the program

Privacy Protection: since there is no need to trust each other between nodes, there is no need to disclose the identity between nodes, and the privacy of each participating node in the system is protected

3. This is the order of importance: BTC private key, wallet security password, BTC address
the private key is everything and must not be told to anyone
as long as there is a private key, you can re import the wallet and reset the wallet security password
a BTC account can have many addresses, so the least important one is the address. No matter how unimportant, you can't just tell others.

4. Stolen currency and being attacked should be a headache for the exchange and it is difficult to avoid. Large exchanges usually set up their own technical team to develop the transaction payment system. Small and medium-sized exchanges can dock with third-party technical service providers, so the cost of R & D and operation and maintenance is relatively low
the exchange I am familiar with uses the currency payment enterprise version, which is a digital asset security payment system. The general principle is to store the private key locally, bind the exchange's unique client with multiple encryptions, and the system itself does not save the private key, so as to prevent the possibility of digital currency theft from the source. It is also convenient to operate, with unified management of Multi Chain and multi currency and convenient reconciliation
hope to adopt.

5. 1. The value of bitcoin does not lie in its computing method and encryption algorithm. 2. The calculation and proction of bitcoin need time, equipment loss and electricity cost. 3. The total output of the algorithm is limited. 4. Some foreign and domestic objects have supported bitcoin payment, which makes it have the preliminary property of currency. 5. There is no difference between bitcoin and the legal currency of any country in its own value. A piece of printed paper or PVC does not have actual value. It can not have the characteristics of rare metals like gold. 6. The biggest risk of bitcoin is that no country, bank, military or government can guarantee its credibility. 7. At present, it seems to be just a virtual currency with speculation value. 8. Its circulation value is certainly not as popular as q-coin in China. For example, few people in second tier cities know about bitcoin, let alone let it admit its value.

6.

there are about three kinds of currency in currency speculation. one is the base currency, which is similar to the representative of money. CNY and usdt Basic goods with value). One is the mainstream token, BTC, ETH (because of the national restrictions, the exchange can only trade in token, that is, take one kind of virtual currency to buy another kind of virtual currency, I don't know why.) The other is a variety of virtual currencies (commodities)

the purchase process is to first go to the exchange platform to find a personal seller with RMB to exchange for usdt, In the process of using usdt to exchange for the mainstream token BTC or eth used in purchasing various virtual coins, and finally using eth to purchase various virtual coins

A. base currency: CNY, usdt (exchangeable, need to be exchanged in good faith transactions with indivial buyers) B. mainstream token: BTC, ethc, virtual currency: all kinds of money, such as profit, need to be exchanged into usdt again, and then sold into CNY. Learn more about the coin circle

< blockquote >

sharing area network ~ learn more about the coin circle

< / blockquote >

experience: 1. Buy mainstream currency if you can't buy it. 2. If the new currency is not fried in January, it may become a banker to harvest leeks. 3. Just learned an experience, chasing up and killing down, meaning up do not buy, buy must be cut leeks If you have strength and value, you can hold it and wait for salted fish to turn over. 5. If the company is strong, the team is strong, and the executives are strong, you can pay more attention to it. Note: I don't understand the K line at all, and I don't understand the professional words, so I can only make a tentative decision on these purchase principles based on logical thinking

7.

As an emerging technology, blockchain has attracted more and more attention. It is a new application of traditional technology in the Internet era, including distributed data storage technology, consensus mechanism and cryptography. With the establishment of various blockchain research alliances, more and more funds and personnel support related research. Hash algorithm, zero knowledge proof, ring signature and other cryptographic algorithms used in blockchain:

hash algorithm

as the basic technology of blockchain, the essence of hash function is to map a set of data of any length (limited) to a set of defined length data stream. If this function satisfies the following conditions:

(1) the calculation of hash value for any group of data is very simple

(2) it is difficult to find two different data with the same hash value

hash functions satisfying the above two properties are also called encrypted hash functions. In case of no contradiction, hash functions usually refer to encrypted hash functions. For the hash function, finding such that is called a collision. The current popular hash functions are MD5, SHA1, Sha2, Sha3

bitcoin uses sha256, and most blockchain systems use sha256 algorithm. So here's sha256< Step 1: additional filling bits. The length of the message is congruent with that of 448 mod512 (length = 448 mod512). The number of bits to be filled ranges from 1 to 512. The highest bit of the filled bit string is 1, and the rest bits are 0

Step2: additional length value. The bit length of the initial message (before filling) represented by 64 bit is appended to the result of step 1 (the low byte takes precedence)

Step3: initialize cache. A 256 bit cache is used to store the intermediate and final results of the hash function

Step 4: process 512 bit (16 word) packet sequence. The algorithm uses six basic logic functions and consists of 64 steps of iterative operation. Each step takes the 256 bit cache value as the input, and then updates the cache content. Each step uses a 32-bit constant KT and a 32-bit wt. Where WT is the packet after the packet, t = 1,2,..., 16

step5: after all 512 bit packets are processed, the output of the last packet of sha256 algorithm is 256 bit packet< In 2001, Rivest, Shamir and TauMan proposed ring signature for the first time. It is a simplified group signature, only ring members have no manager, and it does not need the cooperation between ring members. In the ring signature scheme, the signer first selects a temporary signer set, which includes signers. Then the signer can generate the signature independently by using his private key and the public key of others in the signature set without the help of others. Members of the signer collection may not know that they are included in it

ring signature scheme consists of the following parts:

(1) key generation. A key pair (public key PKI, private key ski) is generated for each member of the ring

(2) signature. The signer uses his private key and the public keys of any n ring members (including himself) to generate the signature a for the message M

(3) signature verification. According to the ring signature and message M, the verifier verifies whether the signature is signed by the member in the ring. If it is valid, it will be received, otherwise it will be discarded

ring signature satisfies the following properties:

(1) unconditional anonymity: the attacker can not determine which member of the ring generated the signature, even if the private key of the ring member is obtained, the probability is not more than 1 / n

(2) Correctness: the signature must be verifiable by all others

(3) unforgeability: other members of the ring can't forge the real signer's signature, and even if an external attacker obtains a valid ring signature, he can't forge a signature for message M

(1) anonymity. The verifier can verify that the signature is signed by a member of the group, but can't know which member it is, so that the signer can be anonymous< (2) traceability. In group signature, the existence of group administrator ensures the traceability of signature. The group administrator can revoke the signature and expose the real signer. The ring signature itself cannot reveal the signer unless the signer wants to expose or add additional information to the signature. A verifiable ring signature scheme is proposed. In this scheme, the real signer wants the verifier to know his identity. At this time, the real signer can confirm his identity by disclosing his secret information< (3) management system. Group signature is managed by group administrator, ring signature does not need to be managed, signer can only select a set of possible signers, obtain its public key, and then publish the set, all members are equal

the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system< br />

8. When it comes to Xu Mingxing, no one in the chain knows that he was deeply influenced by Ma Yun and chose to drop out of school to start a business. After two times of exploration and training, he began to change from an entrepreneur to an entrepreneur. As a believer in blockchain cryptopunk, Xu Mingxing founded okcoin, the predecessor of okcloud chain, in order to create "Alibaba" in the blockchain world. After years of ups and downs, OKC cloud chain has become the world's leading blockchain technology R & D and service provider.