A transfers BTC to B double flower attack
Publish: 2021-05-26 06:15:06
1. After the ZF policy, the domestic bitcoin exchanges were basically closed on October 31. Therefore, if bitcoin wants to be realized, it can only be traded on the OTC exchanges of bitcoin abroad. Many of these closed platforms have opened OTC exchanges abroad, but I don't use much. I only use the coinbee platform and sell a few coins. This is how his OTC trades, The basic routines are the same. First you have to register your account, then get your wallet address from the coinbee platform, then recharge the bitcoin into it, choose to publish advertisements, choose the quantity, price, acceptable transfer method, such as Alipay or bank transfer, if someone wants to buy your currency, he will Send a transaction request to you. Then you trust bitcoin, wait for him to call you, and click on the platform to complete the payment. After you confirm that you have received the payment, you can click release bitcoin on the platform to complete the transaction. This is my actual operation. There will be risks. Be careful. This is my personal practice, and I hope it will be useful to the subject.
2.
It can't turn. These are proxy websites, where can I convert currency
according to the 2017 Credit Suisse report, the number of millionaires in the world is about 36 million. Therefore, if a "bitcoin club" composed of users with more than one bitcoin is established, the number of members of the club will not exceed 21 million, less than the number of global millionaires
bitcoin is graally released through the so-called "mining", and today it has issued more than 85% of the total. It's going to get slower and slower, and it's going to stop completely by about 2140. At present, bitcoin's annualized inflation rate (3.7%) is far lower than that of the US dollar since 2008 (36%), and it will further drop to 1.7% after half a day's rection next year
theoretically, one bitcoin can be infinitely subdivided by expanding the precision of digital storage or by upper layer expansion (such as lightning network technology). However, the transfer fee actually limits the value of bitcoin, which is too small. Therefore, the current code only supports subdivision to one in 100 million. The unit calls it "cong", which is named by netizens in memory of the inventor of bitcoin, Nakamoto. Don't say that one bitcoin is too expensive, because you can buy 0.1 or 0.01
bitcoin is in the address. Address is a number, but for the convenience of writing and using, it is encoded into a string form. The bitcoin address is generated by the private key of bitcoin through cryptographic calculation. This generation process does not need Networking (because mathematical calculation does not need Networking), and can be generated offline on your own computer
3. In the process of learning blockchain, you will hear the word "double flower", which means double payment, or more directly, a sum of money has been spent twice. In this article, we will briefly analyze why there are double flowers and how bitcoin can avoid double flowers
in the traditional transaction, there is no double spending problem because there is a centralized institution such as a bank: every payment will be dected from your bank account, and all details will be recorded in the bank. But in bitcoin, because there is no concept of account, utxo is introced, that is, no transaction output is spent. Because there is no guarantee from centralized institutions such as banks, when a transaction occurs, there may be a risk of double spending: for example, a has a bitcoin, and then he constructs two transactions T1 and T2 at the same time to spend the bitcoin, one of which is given to B, to buy a suit from B, one is given to C, and to buy a pair of shoes from C. If we do not introce some mechanism to avoid this situation, bitcoin, as a digital currency, will not have any meaning of existence. Next, let's analyze how bitcoin can prevent this "double flower" attack
(1) normal situation
first of all, let's look at the normal situation. To put it bluntly, most of the time, the consensus mechanism of blockchain can nip Shuanghua in the bud. Let's illustrate with the above examples:
suppose that a constructs two transactions T1 and T2, and transfers its own value of 1btc utxo to B and C respectively, in an attempt to obtain benefits from B and C at the same time. Then a broadcasts the two constructed transactions to the network almost at the same time
suppose that the miner node in the network receives the transaction T1 first, and finds that the source of funds for the transaction has not been spent, so it adds T1 to its own memory transaction pool and waits to be packaged into the block
in most cases, the miner node will receive transaction T2 soon. At this time, the miner node will refuse to process the transaction because the transaction input that T2 points to is the same as T1 that has been added to the transaction pool. Other miner nodes in the network are similar, so a's attempt to double flower is stillborn
(2) bifurcation
the above is normal, but there are also abnormal cases to consider: suppose that the miner nodes M1 and M2 dig out the block almost at the same time, and unfortunately M1 only receives transaction T1 when digging in the block, while M2 only receives transaction T2 when digging in the block, so transaction T1 and T2 are packed into two blocks respectively. Because these two blocks were g out at about the same time, resulting in the bifurcation of the blockchain:
some nodes in the network (which may be close to M1) received the block blk1 packed by M1 first, so they used the block to extend their own blockchain, while other nodes (which are close to M2) received the block blk2 packed by M2 first, and used the block to extend their own blockchain, So the whole blockchain network
in the traditional transaction, there is no double spending problem because there is a centralized institution such as a bank: every payment will be dected from your bank account, and all details will be recorded in the bank. But in bitcoin, because there is no concept of account, utxo is introced, that is, no transaction output is spent. Because there is no guarantee from centralized institutions such as banks, when a transaction occurs, there may be a risk of double spending: for example, a has a bitcoin, and then he constructs two transactions T1 and T2 at the same time to spend the bitcoin, one of which is given to B, to buy a suit from B, one is given to C, and to buy a pair of shoes from C. If we do not introce some mechanism to avoid this situation, bitcoin, as a digital currency, will not have any meaning of existence. Next, let's analyze how bitcoin can prevent this "double flower" attack
(1) normal situation
first of all, let's look at the normal situation. To put it bluntly, most of the time, the consensus mechanism of blockchain can nip Shuanghua in the bud. Let's illustrate with the above examples:
suppose that a constructs two transactions T1 and T2, and transfers its own value of 1btc utxo to B and C respectively, in an attempt to obtain benefits from B and C at the same time. Then a broadcasts the two constructed transactions to the network almost at the same time
suppose that the miner node in the network receives the transaction T1 first, and finds that the source of funds for the transaction has not been spent, so it adds T1 to its own memory transaction pool and waits to be packaged into the block
in most cases, the miner node will receive transaction T2 soon. At this time, the miner node will refuse to process the transaction because the transaction input that T2 points to is the same as T1 that has been added to the transaction pool. Other miner nodes in the network are similar, so a's attempt to double flower is stillborn
(2) bifurcation
the above is normal, but there are also abnormal cases to consider: suppose that the miner nodes M1 and M2 dig out the block almost at the same time, and unfortunately M1 only receives transaction T1 when digging in the block, while M2 only receives transaction T2 when digging in the block, so transaction T1 and T2 are packed into two blocks respectively. Because these two blocks were g out at about the same time, resulting in the bifurcation of the blockchain:
some nodes in the network (which may be close to M1) received the block blk1 packed by M1 first, so they used the block to extend their own blockchain, while other nodes (which are close to M2) received the block blk2 packed by M2 first, and used the block to extend their own blockchain, So the whole blockchain network
4. Analyzing the advantages of LBTC from the perspective of code mechanism
dpos mechanism
in recent years, e to the resource waste of pow, unstable block output, and the existence of computing power attack, although POW is recognized as the most widely used and secure consensus mechanism, there is still a great risk of being attacked for the block chain with insufficient computing power in the whole network. More and more consensus mechanisms are proposed to be used in blockchain projects for trial and experiment. Dpos is one of the mainstream consensus mechanisms, and LBTC has adopted this mechanism. Dpos ensures that the voting right is in the hands of the coin holder, so the coin holder will be able to choose whether to pass the motion by voting, so as to determine the development direction of the project. At the same time, it also means that the development direction of the project depends on the hands of the people who care about the project itself, and the power of wisdom will promote the better development of the project. At the same time, the advantages of dpos mechanism are that there is no computing power attack, strictly abide by the time block and save resources
dpos advantages of LBTC
the dpos mechanism of LBTC also has its own characteristics: the number of nodes of LBTC is 101, compared with 21 or 51 nodes, the coin holder can vote for 51 nodes at most once in the wallet of LBTC, which further reces the risk of centralization; LBTC can output blocks stably in 3 seconds, and the block size of 2m ensures that LBTC is 400 times more efficient than bitcoin, and the transaction speed can reach more than 2000 transactions per second; The most important difference between LBTC and other projects is that LBTC's dpos mechanism has the rule of irreversible block. When the number of block agents reaches 90% or more in one round, or when the number of block agents exceeds 70%, the first block in the previous round can be considered as irreversible, so as to prevent bifurcation
LBTC's defense measures
in addition to dpos consensus mechanism, LBTC's technical level has other highlights
first of all, LBTC can prevent [replay attack]. What is a replay attack? Each bitcoin account will have a corresponding number of lbtcs based on its bitcoin balance. If the address, private key, algorithm, etc. on each chain are the same, and the transaction format is the same, the transaction initiated on one blockchain can be put on another blockchain for rebroadcasting, and may also be confirmed. This is the "replay attack.". In short, when a user transfers LBTC, BTC may also be transferred at the same time. LBTC modifies the hash algorithm in transaction signature. In the hash algorithm, "LBTC" field is added to LBTC. The hash generated by LBTC and BTC will be different. LBTC and bitcoin do not recognize each other's transactions, so as to prevent replay attacks
secondly, to prevent [forged mining]. There are no concepts of voting and balance in bitcoin transaction. In order to maximize the stability of LBTC, a new output composed of OP return is added in coinbase transaction. Op-return data is composed of three fields: publickey, time and sign (time). Time represents the timeliness of transaction. Publickey verifies sign (time), which is the principle of asymmetric encryption algorithm to prevent forgery and mining. LBTC has 101 nodes. Assuming that the attacker has 30 nodes, if the remaining 71 nodes are forged, other nodes can mistakenly think that the attacker's chain is the longest and block out. This is a forgery mining attack
thirdly, prevent [double flower attack]. Double spending attack is a money spent twice, it can also be called double payment attack. For example, BTG, which has attracted wide attention before, recently suffered 51% attacks. A malicious miner obtained at least 51% of the computing power of the BTG network, temporarily controlled the BTG blockchain, quickly raised money after recharging the exchange, then reversed the block, and successfully implemented Shuanghua. Due to the irreversible block mentioned above, when the transaction of LBTC block is confirmed, it is impossible to roll back, so as to prevent the double flower attack
Fourth, multithreading. In LBTC's transaction consistency and legitimacy check, the data that can be merged and integrated are merged and executed by multi thread, which greatly improves the transaction efficiency and enhances the performance of LBTC
code logic of LBTC
in addition, in terms of code logic, LBTC is divided into protocol layer, consensus layer and application layer. When it is necessary to transfer value, the transaction is completed through the protocol layer link and consensus layer. This process can not only be used as the exchange of value, but also as the value intermediary in the tripartite connection. The application layer is mainly based on smart contract. In the future, LBTC will realize the function of gateway based on smart contract. The payment gateway implements asset issuance, asset transaction, currency exchange, chain interaction and so on
that's why LBTC can say that it wants to do global value internet protocol. Through the payment gateway, it can exchange any currency, not only between currencies, but also between legal currency and digital currency. Isn't that very convenient? One click conversion is to buy eth with vnd and transfer it to her British cousin in the distance. She dislikes it and immediately changes it to EOS. After one second, it is changed to pound sterling. There is no need for extra conversion steps. It's good to get it in one step? Such an analysis, in fact, from the technical code level analysis of LBTC is quite reliable. However, compared with those experts, Xiaobian won't deceive you. Whether LBTC can realize decentralized value Internet Protocol in the future, focusing on code will be a more intuitive way GitHub of LBTC: https://github.com/lbtcio/lbtc-core
how to use gateway
next, we talk about the specific implementation of the gateway's "conversion and circulation", which can be roughly divided into three kinds:
first, after the LBTC system has built the gateway technology, with the gateway as the bridge, user a can convert any currency into LBTC, and then send it to any user B who wants to send it, while user B can convert LBTC into any currency he needs, Does this sound like what you usually do on the exchange? I think this is one of the reasons why LBTC proposes to be a "decentralized exchange"
Second, user a can deposit the funds in the gateway trusted by user B and transfer them to user B through the gateway
thirdly, LBTC will provide the function of "any user can issue token" in the early stage of gateway construction. Therefore, in the LBTC system, if user a has a good reputation, is recognized by everyone, and issues its own a token (of course, it should include the asset chain realized by asset mortgage), a can use its own a token for user B's currency exchange. After that, user a can redeem the a token exchanged to B. A is the gateway role in the transaction process
in the process mentioned above, the functions of asset issuance, asset transaction, currency exchange and chain interaction are realized respectively
the gateway is similar to the function of a bank, which can mainly solve the problem of cross-border transfer. With the high TPS and low handling charge of LBTC, it will be very convenient to realize cross-border transfer. For example, if you need to remit money from China to the U.S., you need to remit RMB to China's LBTC gateway, and then the U.S. gateway will receive the LBTC from China's gateway, convert it into U.S. dollars, and forward it to the U.S. account. In the above gateway system, it can be concluded that both payment parties do not need to join the network, just need to trust the gateway
although the gateway solves the problems of slow speed and high handling charge of traditional transfer payment, it also faces new problems
then there is a problem
in addition to the standard institutions or project parties invited by LBTC can become gateways, ordinary users can buy and sell with each other (in fact, this kind of behavior is more inclined to loan, if it is only the business between acquaintances, it will form a small independent network), How to prove that gateway is a trustworthy organization or indivial
how to extend the gateway of LBTC to cooperate with large organizations is obviously a problem for the team. Ripple has developed more mature. At present, it has cooperated with MUFG in Japan, Westpac in Australia and Standard Chartered Bank in the UK. With ripple, star currency and other payment digital currencies in front, LBTC needs to have more characteristics if it wants to go out of its own route. This can be expected in the later intelligent contract route planning
however, ripple is also accused of being too centralized because of its distribution mode. LBTC has 101 nodes because of its dpos mechanism, and because it is a bifurcated coin, it will be distributed to bitcoin holders 1:1 when it is issued. This can be said to be the inherent advantage of LBTC - it has wide dispersion. If it can be supported and recognized by the public in the future, it can reach a consensus, Then it will form a congenital advantage of wide distribution
in addition, how can we prove that assets really exist in reality and can be used as collateral in the process of asset chain? In addition to large-scale institutions such as banks, small-scale network also has its inevitability. The proof of assets on the asset chain is a very important part. If it is not regulated and certified, it is very likely that the gateway will run away or false gateway will occur. Although the gateway is exemplified as "Taobao" platform, in theory, the platform can not manage the business content, but the platform has supervision on the quality of goods, otherwise it will cause confusion
decentralized exchanges
let's go back to the first point and talk about my ideas on decentralized exchanges. At present, mines and centralized exchanges are the protagonists in the early development of blockchain. With the rise of more and more exchanges, centralized exchanges fall into manipulation scandals and so on, which bring room for the growth of decentralized exchanges. Decentralized transaction is very likely to bring value to the field of blockchain and become the real protagonist in the era of blockchain. With gateway technology, LBTC can realize decentralized exchange. In the decentralized exchange of LBTC, the user's own currency will be kept by himself, which prevents the possibility of losing the currency in the centralized exchange. At the same time, it can also prevent the opaque system transactions, operational and technical risks. According to the previous gateway interview, LBTC will also work with reliable project parties to put on the stock exchange for the benefit of all community members. Generally speaking, LBTC's development route is relatively clear, and its goal in the field of payment is also very clear. Hold on, partners, the future is promising!
dpos mechanism
in recent years, e to the resource waste of pow, unstable block output, and the existence of computing power attack, although POW is recognized as the most widely used and secure consensus mechanism, there is still a great risk of being attacked for the block chain with insufficient computing power in the whole network. More and more consensus mechanisms are proposed to be used in blockchain projects for trial and experiment. Dpos is one of the mainstream consensus mechanisms, and LBTC has adopted this mechanism. Dpos ensures that the voting right is in the hands of the coin holder, so the coin holder will be able to choose whether to pass the motion by voting, so as to determine the development direction of the project. At the same time, it also means that the development direction of the project depends on the hands of the people who care about the project itself, and the power of wisdom will promote the better development of the project. At the same time, the advantages of dpos mechanism are that there is no computing power attack, strictly abide by the time block and save resources
dpos advantages of LBTC
the dpos mechanism of LBTC also has its own characteristics: the number of nodes of LBTC is 101, compared with 21 or 51 nodes, the coin holder can vote for 51 nodes at most once in the wallet of LBTC, which further reces the risk of centralization; LBTC can output blocks stably in 3 seconds, and the block size of 2m ensures that LBTC is 400 times more efficient than bitcoin, and the transaction speed can reach more than 2000 transactions per second; The most important difference between LBTC and other projects is that LBTC's dpos mechanism has the rule of irreversible block. When the number of block agents reaches 90% or more in one round, or when the number of block agents exceeds 70%, the first block in the previous round can be considered as irreversible, so as to prevent bifurcation
LBTC's defense measures
in addition to dpos consensus mechanism, LBTC's technical level has other highlights
first of all, LBTC can prevent [replay attack]. What is a replay attack? Each bitcoin account will have a corresponding number of lbtcs based on its bitcoin balance. If the address, private key, algorithm, etc. on each chain are the same, and the transaction format is the same, the transaction initiated on one blockchain can be put on another blockchain for rebroadcasting, and may also be confirmed. This is the "replay attack.". In short, when a user transfers LBTC, BTC may also be transferred at the same time. LBTC modifies the hash algorithm in transaction signature. In the hash algorithm, "LBTC" field is added to LBTC. The hash generated by LBTC and BTC will be different. LBTC and bitcoin do not recognize each other's transactions, so as to prevent replay attacks
secondly, to prevent [forged mining]. There are no concepts of voting and balance in bitcoin transaction. In order to maximize the stability of LBTC, a new output composed of OP return is added in coinbase transaction. Op-return data is composed of three fields: publickey, time and sign (time). Time represents the timeliness of transaction. Publickey verifies sign (time), which is the principle of asymmetric encryption algorithm to prevent forgery and mining. LBTC has 101 nodes. Assuming that the attacker has 30 nodes, if the remaining 71 nodes are forged, other nodes can mistakenly think that the attacker's chain is the longest and block out. This is a forgery mining attack
thirdly, prevent [double flower attack]. Double spending attack is a money spent twice, it can also be called double payment attack. For example, BTG, which has attracted wide attention before, recently suffered 51% attacks. A malicious miner obtained at least 51% of the computing power of the BTG network, temporarily controlled the BTG blockchain, quickly raised money after recharging the exchange, then reversed the block, and successfully implemented Shuanghua. Due to the irreversible block mentioned above, when the transaction of LBTC block is confirmed, it is impossible to roll back, so as to prevent the double flower attack
Fourth, multithreading. In LBTC's transaction consistency and legitimacy check, the data that can be merged and integrated are merged and executed by multi thread, which greatly improves the transaction efficiency and enhances the performance of LBTC
code logic of LBTC
in addition, in terms of code logic, LBTC is divided into protocol layer, consensus layer and application layer. When it is necessary to transfer value, the transaction is completed through the protocol layer link and consensus layer. This process can not only be used as the exchange of value, but also as the value intermediary in the tripartite connection. The application layer is mainly based on smart contract. In the future, LBTC will realize the function of gateway based on smart contract. The payment gateway implements asset issuance, asset transaction, currency exchange, chain interaction and so on
that's why LBTC can say that it wants to do global value internet protocol. Through the payment gateway, it can exchange any currency, not only between currencies, but also between legal currency and digital currency. Isn't that very convenient? One click conversion is to buy eth with vnd and transfer it to her British cousin in the distance. She dislikes it and immediately changes it to EOS. After one second, it is changed to pound sterling. There is no need for extra conversion steps. It's good to get it in one step? Such an analysis, in fact, from the technical code level analysis of LBTC is quite reliable. However, compared with those experts, Xiaobian won't deceive you. Whether LBTC can realize decentralized value Internet Protocol in the future, focusing on code will be a more intuitive way GitHub of LBTC: https://github.com/lbtcio/lbtc-core
how to use gateway
next, we talk about the specific implementation of the gateway's "conversion and circulation", which can be roughly divided into three kinds:
first, after the LBTC system has built the gateway technology, with the gateway as the bridge, user a can convert any currency into LBTC, and then send it to any user B who wants to send it, while user B can convert LBTC into any currency he needs, Does this sound like what you usually do on the exchange? I think this is one of the reasons why LBTC proposes to be a "decentralized exchange"
Second, user a can deposit the funds in the gateway trusted by user B and transfer them to user B through the gateway
thirdly, LBTC will provide the function of "any user can issue token" in the early stage of gateway construction. Therefore, in the LBTC system, if user a has a good reputation, is recognized by everyone, and issues its own a token (of course, it should include the asset chain realized by asset mortgage), a can use its own a token for user B's currency exchange. After that, user a can redeem the a token exchanged to B. A is the gateway role in the transaction process
in the process mentioned above, the functions of asset issuance, asset transaction, currency exchange and chain interaction are realized respectively
the gateway is similar to the function of a bank, which can mainly solve the problem of cross-border transfer. With the high TPS and low handling charge of LBTC, it will be very convenient to realize cross-border transfer. For example, if you need to remit money from China to the U.S., you need to remit RMB to China's LBTC gateway, and then the U.S. gateway will receive the LBTC from China's gateway, convert it into U.S. dollars, and forward it to the U.S. account. In the above gateway system, it can be concluded that both payment parties do not need to join the network, just need to trust the gateway
although the gateway solves the problems of slow speed and high handling charge of traditional transfer payment, it also faces new problems
then there is a problem
in addition to the standard institutions or project parties invited by LBTC can become gateways, ordinary users can buy and sell with each other (in fact, this kind of behavior is more inclined to loan, if it is only the business between acquaintances, it will form a small independent network), How to prove that gateway is a trustworthy organization or indivial
how to extend the gateway of LBTC to cooperate with large organizations is obviously a problem for the team. Ripple has developed more mature. At present, it has cooperated with MUFG in Japan, Westpac in Australia and Standard Chartered Bank in the UK. With ripple, star currency and other payment digital currencies in front, LBTC needs to have more characteristics if it wants to go out of its own route. This can be expected in the later intelligent contract route planning
however, ripple is also accused of being too centralized because of its distribution mode. LBTC has 101 nodes because of its dpos mechanism, and because it is a bifurcated coin, it will be distributed to bitcoin holders 1:1 when it is issued. This can be said to be the inherent advantage of LBTC - it has wide dispersion. If it can be supported and recognized by the public in the future, it can reach a consensus, Then it will form a congenital advantage of wide distribution
in addition, how can we prove that assets really exist in reality and can be used as collateral in the process of asset chain? In addition to large-scale institutions such as banks, small-scale network also has its inevitability. The proof of assets on the asset chain is a very important part. If it is not regulated and certified, it is very likely that the gateway will run away or false gateway will occur. Although the gateway is exemplified as "Taobao" platform, in theory, the platform can not manage the business content, but the platform has supervision on the quality of goods, otherwise it will cause confusion
decentralized exchanges
let's go back to the first point and talk about my ideas on decentralized exchanges. At present, mines and centralized exchanges are the protagonists in the early development of blockchain. With the rise of more and more exchanges, centralized exchanges fall into manipulation scandals and so on, which bring room for the growth of decentralized exchanges. Decentralized transaction is very likely to bring value to the field of blockchain and become the real protagonist in the era of blockchain. With gateway technology, LBTC can realize decentralized exchange. In the decentralized exchange of LBTC, the user's own currency will be kept by himself, which prevents the possibility of losing the currency in the centralized exchange. At the same time, it can also prevent the opaque system transactions, operational and technical risks. According to the previous gateway interview, LBTC will also work with reliable project parties to put on the stock exchange for the benefit of all community members. Generally speaking, LBTC's development route is relatively clear, and its goal in the field of payment is also very clear. Hold on, partners, the future is promising!
5. All bitcoin addresses and related transactions are transparent and searchable. Some people call it "semi anonymous" or "pseudo anonymous" transaction mechanism. In theory, the IP information is traceable.
6. Transfer steps:
1. After confirming that the passbook account number and account name provided by the payee are correct, take the cash to the bank and deposit it directly into the payee's account number
2. You can open an account in the bank, then fill in a telegraphic transfer form, fill in the opposite party's collection account number, account name, and bank name, and remit money from the account to the payee
3. If it's troublesome to open an account, you can remit money directly in cash and fill in a telegraphic transfer form for remittance, but you must fill in the recipient's account number, account name and bank name clearly
4. Open online banking, and you can make online payment and transfer by yourself. Transfer method:
1. After confirming that the passbook account number and account name provided by the payee are correct, take the cash to the bank and deposit it directly into the payee's account number
2. You can open an account in the bank, then fill in a telegraphic transfer form, fill in the opposite party's collection account number, account name, and bank name, and remit money from the account to the payee
3. If it's troublesome to open an account, you can remit money directly in cash and fill in a telegraphic transfer form for remittance, but you must fill in the recipient's account number, account name and bank name clearly
4. Open online banking, and you can make online payment and transfer by yourself. Transfer method:
7. Bonus system is not the key to success, so we should choose it carefully
8. Introction: Beijing Weigang blockchain Technology Co., Ltd. focuses on blockchain public chain technology innovation and smart contract economic application practice. We are the basic service provider of blockchain. We help enterprises to link up, and help "Internet plus" enterprises upgrade to "block chain +".
legal representative: Cao Yi
time of establishment: May 21, 2018
registered capital: RMB 10 million
enterprise type: other limited liability company
address: room 335, ground floor, No. 36, Haidian West Street, Haidian District, Beijing
legal representative: Cao Yi
time of establishment: May 21, 2018
registered capital: RMB 10 million
enterprise type: other limited liability company
address: room 335, ground floor, No. 36, Haidian West Street, Haidian District, Beijing
9.
On July 1, 2002, Russian bus Kiel Airlines flight 2937 (btc2937) originally planned to fly from Moscow, the capital of Russia, to Barcelona, Spain. DHL express company flight 611 (dhx611), the original route is from Bahrain International Airport via Italy's Bergamo International Airport to Belgium's Brussels
two planes collided at 21:35 on (UTC + 8) July 1, 2002 over the Swiss city of ublingen on the Bank of Lake Bodensee in southern Germany. The vertical tail of flight 611 passed the lower left side of flight 2937, and the Tu-154 exploded and disintegrated into two sections
Flight 611 lost control and barely flew 7 km. Two minutes later, it crashed near a mountainside. One of its engines exploded and detached from the wing before the crash. A total of 71 passengers and crew members on the two flights were killed{rrrrrrr}
extended information:
other heavy air disasters in the world
1. Tenerife air crash, 583 people were killed
in the evening of March 27, 1977, on the runway of Los Rodeo airport in the autonomous Canary Islands off the North African coast of Spain, Two Boeing 747s loaded with fuel and passengers from Royal Dutch Airlines and Pan American Airlines collided. A total of 583 people on the two planes were killed in the flames
2. The air crash of JAL 123 killed 520 people.
the air crash of JAL 123 occurred on August 12, 1985. This Boeing 747-100sr flight, carrying 509 passengers and 15 crew members, is scheled to fly from Tokyo's Haneda airport to Osaka's IDAN airport
3. The air crash of Saudi Arabian Airlines flight 763 killed 349 people on November 12, 1996. The newly taking off flight 763 of Arabian Airlines and flight 1907 of Kazakhstan Airlines collided over chakidari near New Delhi, killing 349 people on both flights. This is the most serious air collision in the world's top ten air accidents
On August 19, 1980, after taking off from Riyadh International Airport, Saudi Arabian Airlines flight 163 reported a fire in the cargo hold. Although the plane successfully turned back, a total of 301 people on board did not survive May 25th, 1979 is a traditional American holiday, the memorial day of the dead. As one of the busiest airports in the world, O'Hare International Airport is actively transporting tourists to Los Angeles for vacation on that day. However, on that day, after the take-off of American Airlines flight 191, there was a major accident of engine falling offHot content