Dpom digital currency exchange
If you want to understand the application of blockchain, you can refer to many books and opinions, such as illustrated blockchain, blockchain: reshaping the economy and the world, blueprint and guide of new economy, and articles of coin'an community, including a detailed understanding of the platform of coin'an community, with great strength
As the name suggests, blockchain is composed of block and chain. It is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and so on. It is a kind of chain data structure that combines data blocks in order according to the time sequence, and it is a secure and reliable distributed account book that can not be tampered with and forged by means of cryptographyin 2008, in his paper bitcoin: a peer-to-peer e-cash system published by Nakamoto, he first proposed the idea of blockchain and encrypted digital currency. Starting from bitcoin, blockchain has become the underlying technology of various digital currencies
2. Working principle of blockchain:
1. Basic concepts include:
(1) transaction: one operation will change the account status once, such as adding a record
(2) block: records the transaction and status data within a specified time, which is a consensus and preservation of the current account status
(3) chain: it is composed of a series of blocks in chronological order, which is the log record of the whole state change
if you understand the working concept of blockchain, it is not difficult to understand its working principle. Suppose there is a distributed data logbook, which can only be added, deleted or changed. Its structure is a linear chain formed by a series of "blocks" (which is also the source of the name of "blockchain"), and new data needs to be added, It must be put into a new block. The maintenance node can propose a new block, but it must go through a certain consensus mechanism to reach an agreement on the final selected block
2. Take bitcoin as an example to see the working principle of blockchain
the block of bitcoin is divided into block head and block body< The core advantages and characteristics of blockchain are as follows:
3.
1. The verification, accounting, storage, maintenance and transmission of blockchain data are all based on the distributed system structure. There is no centralized hardware or management organization, and the rights and obligations of any node are equal, The data blocks in the system are jointly maintained by the nodes with maintenance function in the whole system
2. Open and transparent
the system is open, in addition to the private information of all parties to the transaction is encrypted, the data of the blockchain is open to all, and anyone can query the blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Security
blockchain adopts consensus based specifications and Protocols (such as a set of open and transparent algorithms) to enable all nodes in the whole system to exchange data freely and safely in a de trusted environment, so that the trust in "people" is changed into the trust in machines, and any human intervention does not work
4. Information cannot be tampered with
once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% (almost impossible) nodes in the system can be controlled at the same time, the modification of the database on a single node is invalid, so the data stability and reliability of the blockchain are extremely high
5. Anonymity
because the exchange between nodes follows a fixed algorithm, their data interaction does not need trust (the program rules in the blockchain will judge whether the activity is effective by themselves), so the counterparties do not need to let the counterparties generate trust by disclosing their identities, which is very helpful for credit accumulation
1. Public chain: anyone can participate in the use and maintenance, and can obtain the effective confirmation of the blockchain. Public chain is the earliest blockchain and the most widely used blockchain at present, such as bitcoin blockchain. The information is completely public
if the licensing mechanism is introced, it includes private chain and alliance chain
2. Private chain: a company or indivial only uses the blockchain technology and enjoys the write permission of the blockchain, and the information is not disclosed. At present, conservative giants (traditional finance) want to experiment with private blockchain, and the application procts of private blockchain are still groping
3. Alliance chain: it is a blockchain controlled by multiple organizations, which is between the public chain and the existing chain. The use of the chain is managed with authority, which can be controlled by the manager, and also open to others according to the manager's wishes
in addition, according to the different use scenarios and purposes of blockchain, it can be divided into currency chain for the purpose of digital currency, property chain for the purpose of recording property rights, and crowdfunding chain for the purpose of crowdfunding
take Maotai liquor as an example:
distillery address, proction workshop, operation staff, inspector, delivery time, transportation vehicle information and driver information,
liquor year, raw material source, raw material supplier, storage warehouse number, raw material transportation vehicle and driver information,
all information can be accurately traced, permanently recorded and tampered with
the above information can be easily verified
2. Food safety issues as early as last November, Wal Mart has cooperated with IBM to track the source of food by using blockchain technology, so as to ensure the safety of food and increase the circulation of food to rece costs. For Wal Mart and other large supermarkets, it took a few days to investigate the source of problem food, After using this technology, only one item of proct information is needed to achieve accurate traceability, and important information such as food origin, inspector, supplier, logistics and transportation can quickly find problems in a few minutes. Currently, procts tracked by blockchain include packaging procts from the United States and pork from China
3. Information security
blockchain technology is promoting an information security technology revolution. (1) identity protection PKI is a common public key encryption technology in e-mail, message application, website and other communication applications. However, since the implementation of most PKI, the centralized trusted third party certification authority (CA) is used to issue, activate and store user certificates. Hackers can attack PKI to fake user identity or crack encrypted information
certcoin is the first PKI implementation of blockchain, which comes from MIT, removes the centralized authentication center, and uses blockchain as a distributed ledger for domain name and public key
pomcor company: blockchain PKI implementation path: keep the authentication center, and use blockchain to store the hash value of issued and activated certificates. Users can verify the authenticity of certificates through decentralized and transparent sources, and can also improve the network access performance through local authentication of secret key and signature based on blockchain
(2) data integrity protection
guardtime developed a secret key free signature architecture (Ksi) based on blockchain technology to replace the secret key based data authentication technology. Ksi stores the hash table of the original data and files on the blockchain, runs the hash algorithm to verify other copies, and compares the results with the data stored in the blockchain. Any data tampering will be found quickly because the original hash table is stored in millions of nodes
(3) key infrastructure protection
the "Achilles heel" of the Internet, DDoS has entered the TB era, DDoS is still the simplest weapon for hackers to bring down the big target with low cost, DNS service is the primary target for hackers to carry out large-scale destruction, but blockchain technology is expected to fundamentally solve the problem
The distributed storage ofblockchain makes hacker attacks lose focus. Nebulis is developing a distributed DNS system, which uses Ethereum blockchain and interstellar Internet file system (IPFs, the distributed substitute of HTTP) to register and resolve domain names. The biggest weakness of DNS is caching, which makes DDoS attacks possible. It is also the bane of the centralized government's censorship of social networks and manipulation of DNS registration. A highly transparent and distributed DNS system can effectively prevent any entity, including the government, from arbitrarily manipulating records
(1) digital currency: improve the convenience of currency issuance and use, such as bitcoin and Ethernet in foreign countries, and guorenbao in Chinafrom the use of physical transactions, to physical currency and credit currency, and then to the rise of bitcoin network, more and more people are aware of the distributed ledger blockchain technology behind it, and graally apply it in many scenarios other than digital currency
(2) cross border payment and settlement: realize point-to-point transaction, rece intermediate fees
transfer and payment. At present, the most mature application of blockchain technology is payment and transfer. Blockchain technology can avoid complicated systems, save the process of inter-bank reconciliation and review, and accelerate the settlement speed; Virtual currency can rece transaction costs without the intervention of clearing house. Different countries have different clearing proceres. It takes two or three days for a single remittance to arrive, which is inefficient and accounts for a large proportion of funds in transit. No longer through the third party, through the blockchain technology to form point-to-point payment. By eliminating the link of the third-party institutions, we can make full day payment, real-time payment, withdraw cash quickly and rece the hidden cost, which helps to avoid the capital risk. It is timely and convenient
(3) bills and supply chain financial business: rece human intervention, rece costs and operational risksvalue transfer between point-to-point, control and verify physical bills or central system; Intermediaries will be eliminated and human intervention reced. With the improvement of efficiency, financing channels are more unblocked, risks are lower, and multiple parties benefit
(4) securities issuance and Trading: realize quasi real-time asset transfer, accelerate the speed of transaction clearing
the application of blockchain technology can make the process of securities trading more concise, transparent and fast, rece the plication of IT system, and improve the efficiency of market operation. For stocks, blockchain can eliminate paper and pen or electronic form records, rece human errors in trading, and improve the transparency and traceability of trading platform. Citigroup and Nasdaq cooperate to promote blockchain applications
(5) customer credit investigation and anti fraud: rece the cost of legal compliance, prevent financial crimes
the customer information and transaction records recorded in the blockchain help banks identify abnormal transactions and effectively prevent fraud. The technical characteristics of blockchain can change the existing credit reference system, which can be implemented in banks
Round table is also called lingtai. It is said that because all treasures have aura, ancient emperors and emperors used this furniture when they were resting in the backyard to enjoy the treasures from all over the world. The dining room of Chinese family is a place for family members to get together and exchange feelings, and the round table not only conforms to the diet habit of "sitting around" of the Chinese people's Congress family, but also contains the meaning of "Reunion"
traditional Chinese families are very particular about table and banquet etiquette:
1 family banquet, the chief is the most respected guest, the host is the last. If the chief is not seated, the rest can not be seated. If the chief is not eating with chopsticks, no one can eat with chopsticks. During the wine inspection, the chief of staff should respect the wine in order
2 if it is a round table, the one facing the gate is the host guest, the left side is 2, 4, 6, etc., the right side is 3, 5, 7, etc., until the meeting
3 if there is a seat facing the gate, the right seat facing the gate is the host guest. If it is not facing the gate, the left seat on the east side is the chief. Then the chief's left side is 2, 4, 6 and 8, and his right side is 3, 5 and 7
4 if it's a big banquet, the arrangement between tables should pay attention to that the chief should be in the front and the middle, with 2, 4 and 6 seats on the left and 3, 5 and 7 seats on the right, respectively
The times are changing, and the essence of round table culture is still well inherited. As an important part of Chinese traditional culture, round table reflects the brilliance of Chinese traditional culture and art, and is endowed with deeper significance. In the conference room of the unit and in all kinds of meetings from all walks of life, you can often see a huge oval round table. Although the diameter of the round table is different, it shows the meaning of equality for all. Obviously, the spirit of round table has penetrated into modern people's life, and has become the consensus of the public. The public to buy mahogany round table is not only to buy a proct, but also to buy a culture [Jiaxin big board] bahua round platform wooden table: bahua is a kind of wood name, also known as Brazil pear. Texture crisscross obviously, with light brown stripes, mainly distributed in tropical Africa, with luster; No special smell
round table