3 thoughts on “What is the expansion of Bitcoin? Why expand the capacity?”
Margaret
The size of each block is one trillion, which can accommodate more than a thousand transactions. If you go to the Bitcoin blockchain browser to watch, you will find out that every block is about one trillion now about one trillion It has reached the upper limit of the block capacity. If there are more and more transfers of the Bitcoin network, many transactions will not be packaged and confirmed by the first block after the transaction. It may have to wait for several blocks or more time. In the history of Bitcoin, there have been several dust attacks. Among them, many traders create a large amount of small transfer on the exchange (currency exchange). The manufacture of a large amount of small transfer makes there a lot of transactions to be confirmed in the network, resulting in normal transfer of transfer, which cannot be confirmed. The confirmation time is delayed and affects the normal operation of the network. The trading of many traders is waiting for two days or longer to be confirmed. Although the dust attack is a very extreme example, it is far exceeding the current Bitcoin network. The maximum capacity of each block is now a mega size, so it expands the capacity of Bitcoin block and breaks through the existing restrictions of a mega size. This process is called expansion.
What does expansion mean and why do you need to expand?
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1. The problem of expansion of Bitcoin 1.1 The TPS and the problem of the TPS and handling fees of Bitcoin transactions The size of a bit currency block is 2m, and one block is produced every 10 minutes. Based on this, we can calculate the theory of Bitcoin: TPS (BTC) = block size / tx size / (10 * 60) = 2 * 1024 * 1024 /500 / (10 * 60) ≈ 7 It, it can be seen that about 7 transactions of transactions can be dealt with in the average one second of Bitcoin. In addition, as the number of people using Bitcoin increases, Bitcoin transactions surge, which can easily cause Bitcoin transaction congestion. During congestion, the transaction forms a queue to wait for the upper chain, causing some trouble for users. In addition, transaction congestion can also cause another serious consequences, that is, the transaction fee increases. Bitcoin transactions are packed by miners. Miners are paid by mining rewards and transaction fees. Therefore, miners have the motivation to increase transaction fees. Because users want a lower handling fee and miners hope to be higher, the market will form a balanced and reach the level of fees that you can accept. However, if the transaction is congested, the balance of supply and demand in the market will be broken, and the balance is inclined. Miners can require higher fees (theoretically, miners have the right to choose transactions that are prioritized and packaged). The historical data (above: The vertical axis is a transaction fee for the US dollar pricing), and the Bitcoin single transaction fee has reached the pinnacle of $ 40 at the end of 2017, even within two months before and after Stable on a platform with $ 15-20. In non-active periods, trading fees can generally be maintained between $ 0.3-1.5. Although the fees in the off -season seem to be acceptable, people cannot be satisfied with the status quo. After all, Bitcoin is a cryptocurrency that is hoped to move towards large -scale applications, and should have the ability to deal with large -scale transactions. Because of this, PROBLEM has become the defect of the most criticism. 1.2 Bitcoin's chain of the Bitcoin We have mentioned in the previous article that Bitcoin's followers have realized the severity and urgency of Bitcoin's expansion problem. So how to expand capacity? This is the core link of controversy. The first expansion idea is called on-chain expansion. The so -called chain expansion, as the name suggests, modify the parameters of the consensus agreement to achieve higher TPS data. For Bitcoin, increasing the time interval of blocks, increasing block capacity, and reducing the capacity of transactions are the theoretical feasible ideas. However, Bitcoin, as the largest cryptocurrency system today, can be described as the whole body, and has to be cautious. In fact, in order to prevent the degree of centralization from being lost due to the high threshold of the whole node, Bitcoin is almost impossible to shorten the time interval. As a result, the possibility is compressed to block capacity and transaction capacity. It in terms of transaction capacity occupation, the framework of Bitcoin has determined the format and content of the transaction, which can reduce the room for reduction. After the segwit is upgraded, the structure of the transaction has been optimized, but the changes in this area must be very limited. We we have to turn our eyes to the size of the block. Because the initial agreement of the Bitcoin agrees with a capacity of 1M, and at the moment when the Internet infrastructure is developed at the rapid development, this does not seem to constitute any pressure. Some supporters have proposed that the capacity restrictions and increase the capacity limit. In fact, a bifurcation protocol of Bitcoin-Bitcoin Cash (BCH) did this: BCH directly increased the block capacity to 32M, and threatened to continue to increase significantly in the future. After the Bitcoin is also an isolated testimony, it has obtained nearly 2M block capacity. , but the idea of expanding capacity is questionable: the reason is that the income expansion is limited, but the damage to the decentralization is great. We can make a simple comparison: · Bitcoin cash (BCH) to increase the size to 32M, which can achieve a 16 -fold TPS increase compared to Bitcoin (BTC); · Lightning Bitcoin (LBTC) can achieve an increase of 200 times compared to Bitcoin (BTC) by DPOS based on UTXO. However, increased the volume of the block, which will greatly increase the threshold of the whole node, and the efficiency and speed of the block circulation in the P2P network. This is a problem of worrying about Bitcoin's original teachings. Because of this, Bitcoin (BTC) is extremely cautious in improving block capacity and is always unwilling to let go of restrictions. 1.3 Another idea If the income of expansion on the chain is limited and the potential damage is great, can it be turned to the expansion idea of the non -chain? The answer is okay. The expansion on the non-chain can be solved by the idea of off-chain or cross-chain. The first talk about cross -chain. Cross -chain refers to the substantial higher TPS by binding the Bitcoin network to a higher TPS blockchain. But this requires a recognized cross -chain technical solution, and the Child Chain ecosystem. This approach seems embarrassing because we must introduce a new blockchain. The expansion of the chain is the most concerned and high -feasibility solution that people are most concerned about. The famous Lightning Network is such a chain expansion solution. The meaning of expansion under the chain means that the transaction is reached under the chain and does not occupy the resources on the chain; when a series of transactions are reached, the final result conveys the chain. Understand, you can see that there is a small bank to help you complete a series of transfer transactions, and then send the balance data to the chain regularly. It in the following, we will specifically describe the operating mechanism of the Lightning Network and evaluate whether this expansion method is really effective. 2. The basic operation principle of the lightning network 2.1 Payment channel Matons will have some questions after exposed to the lightning network, for example: Since the lightning network is a transaction under the chain, why are we Can I trust it? This is a good question! If you ask this question, at least it shows that you have a certain understanding of the blockchain. The Lightning Network does complete the transaction under the chain, but I can guarantee that its operating mechanism is very reliable. Lightning network depends on some safe solutions in column passwords to complete the establishment of payment channel establishment, payment and balance change, and even node routing. It we here is a new term: payment channel. The payment channel sounds abstract, but you can understand this: it is a account that opens between two traders, which are maintained by two traders. When a transaction occurs, the transaction will be recorded in this account. After a period of time and several trading, the balance of the account will be registered on the Bitcoin chain. The lightning network is a network of payment channels. Except for the creation and closing of the payment channel, the other operations are under the chain transaction, and the rest of the operation is under the chain. Based on this, the lightning network realizes a good chain expansion, which has greatly extended the trading potential of Bitcoin. 2.2 Payment channels and RSMC transactions The opening, closing, and balance of the payment channel are achieved through a type of transaction type called RSMC. RSMC's full name is Revocable Sequence Maturity Contract, which means that the sequence expires can be revoked, which is composed of a series of transactions to implement specific functions. The us take the payment channel between Alice and BOB to transfer each other and build the payment channel between the two people. Try to simply explain the establishment of the payment channel. The construction steps of the entire channel are as follows: 1) Alice and BOB each take out the BTC that they initially owned and build a Funding transaction. The input of this transaction is the BTC of each of them each; output is a condition for a 2-OF-2 multiple signature. At this time, the Funding transaction has not been signed by the two and has no broadcast. 2) Alice creates two transactions. The input of the first transaction spent a Funding transaction and handed it to the BOB for a good name (at this time Alice was not signed); the transaction contained 2 output structures, and the first output required the multiple of Alice and Bob's multiple Signature (Alice2 represents another private key of Alice), and the second output requires the signature of the BOB. The second transaction points to the first output of the first transaction. It is signed by BOB first, and its own output points to the address of Alice. This transaction has the conditions of Sequence, that is, it is required that the previous transaction must be confirmed that the transaction can be packed into the block. 3) Bob also created two transactions, and the transaction structure is completely symmetrical with the transaction created by Alice. 4) After completing the setting of the above transactions, the two parties signed the Funding transaction and broadcast them. The brief explanation: Funding transactions are to allow the two parties to take out a funds to establish a channel; the role of the later transaction is to allow the two parties to unilaterally request refund (Refund) funds. Both Alice and BOB have the right to unilaterally trigger Refund. However, whoever triggers Refund first, the other party can get Refund immediately, and you have to wait for the Sequence time to get Refund. As a result, both Alice and BOB can cancel channels and terminate cooperation at any time, and can ensure the security of both sides. 2.3 The balance in the payment channel is updated. It now the payment channel has been created. If Alice and BOB want to transfer each other, how should it be operated? During a transaction, the two parties jointly constructed another set of transactions to replace the original transaction and update the balance information in the transaction content. The question is here, the original transaction is still there, and both parties exchanged signatures. How can we abandon it? The method of solving is also very clever. When creating a new transaction, the signature requested by the sponsor is corresponding to a new private key (let alone Alice3, Bob3); at this time, Alice told Bob's original private key Alice2, BOB can modify the original transaction as one The new penalty transaction, the output of the transaction is itself, and cancel the Sequence restrictions; so that the BOB can be broadcast to implement the punishment in case Alice signed the transaction without permission, causing Alice to lose its own funds. Therefore, once Alice told BOB about Alice2, it is equivalent to announced that the original transaction was invalidated. Bob's side is also the same. The principle is really complicated, right? A simple and easy -to -understand conclusion is given: When the transaction balance needs to be updated, the two parties of the transaction can build new transactions to ensure that any of them can unilaterally tamper the balance of funds to make themselves profit. Mena, our doubts are completely solved. In the process of the construction, closure and balance changes of the payment channel, they can ensure that the two parties achieve the construction of related transactions without trust. Therefore, even the payment channel under the chain is completely trusted. 3. The node routing of the lightning network 3.1 Why does it need node routes The establishment of the payment channel to ensure that any two traders can establish a set of sets of transaction balance under the chain to recording transaction balance changes Accounts and realize trading behavior under the framework. , but there is still a problem that has not been resolved. We know that small payment behaviors are often high -frequency and the objects are not fixed, so does it mean that when any two individuals need to complete payment or transfer transactions, they must establish a payment channel between the two? Of course, it is impossible! As mentioned earlier, the establishment and closure of the payment channels are achieved through chain transactions. If users on Lightning Networks need to establish a payment channel with opponent Fang before paying payment, it is no different from trading directly on the chain. This is obviously ridiculous. In order to solve this problem, we need to build a routing mechanism between different payment channels. For example, assuming that Alice has established a payment channel with BOB, and BOB has established a payment channel with his friend Kevin. Now Alice wants to transfer KEVIN, then they can be intermediaries by BOB, through the path of Alice → Bob → Kevin to achieve payment behavior, no additional payment channels are required! 3.2 Payment channel route and HTLC transaction HTLC transaction full name has Hashed Time-Lock Contract, which means a contract locked in hash time. The simple understanding is that the contract is locked by a hash value and a expiration time parameter. I believe that everyone is tired of those extremely complicated technical explanations. The following is a simple example to illustrate the basic principles of HTLC. In the above example, we have found a routing path Alice → Bob → Kevin. We assume that Alice wants to pay 1BTC to Kevin. First of all, the BOB made a safe, stored in 1BTC, and handed it to Kevin; Alice also made a similar safe, deposited 1BTC and handed it over to Bob. The passwords of these two safe are the same, and they need to be provided by Kevin. When Kevin provides a password, this password will be publicized, which means that anyone can see this password. During the transaction execution, Kevin will open the safe sent by the Bob by providing a password to get 1BTC; BOB knows the password, open the safe sent by Alice to get 1BTC. It we noticed that Bob is equivalent to the intermediary in the transaction (ESCROW), and his existence enables Alice → Kevin's transactions. Therefore, theoretically BOB can collect certain commissions as a reward for matching Alice and Kevin. For example, BOB can put 0.99bTC in the safe to Kevin, leaving 0.01BTC as a commission for the transaction. Although our metaphors may not necessarily fully meet the actual situation, I believe it can also roughly explain the principle of HTLC. HTLC is also trusted. This means that we can support high -frequency small payment activities under the chain through a huge network built by countless RSMC and HTLC contracts, and we don't need to worry about the security of funds. 4. Lightning Network vs. LBTC: The dispute between the expansion method 4.1 Some evaluations of the lightning network have to say that the lightning network is a very genius and successful idea, at least it It is already on the way to large -scale implementation. At present, the Bitcoin community is closely concerned about the implementation of the Lightning Network, and the transactions inside the lightning network have a certain degree of activity. but the real large -scale application of the lightning network is a certain distance. I think there may be several problems in the lightning network, or at least it is worthy of attention: 1) Lightning networks have high requirements for infrastructure. Because the positioning of the Lightning Network is small high -frequency payment, there must be supporting equipment and software applications to support the algorithm required for Lightning Network. But if you observe the current situation, you will find that most of the wallets that can support the lightning network are still custody of wallets, not the real decentralized wallet. However, the real decentralized wallet distance is still far away by ordinary users. In this context, the significance of the Lightning Network has some doubts. 2) Lightning network as a payment facility under the chain, the requirements of the intermediary agencies and the transaction will be higher than the chain! Specifically, the intermediary agency needs to be operated online, and the two parties to the transaction can be provided to provide signatures to provide signatures. Construction of RSMC and HTLC transactions. Such a model has challenged the intermediary agency. The fragile and small intermediary agencies are bound to be difficult to survive. In contrast, the chain transaction does not have so many strict requirements for intermediaries and nodes; newly generated bitcoin transactions only need to be thrown into the P2P network, wait for the transaction to be packaged and produce a new block. You don’t need to worry about being too much. More problems. Although some shortcomings are mentioned, it is necessary to say that in actual use, the advantages of fast -to -account networks and low handling fees are existing. In addition, due to the characteristics of the settlement of the lightning network chain, it also has many side advantages such as transaction privacy protection. The us take the payment channel between Alice and BOB to transfer each other and build the payment channel between the two people. Try to simply explain the establishment of the payment channel. The construction steps of the entire channel are as follows: 1) Alice and BOB each take out the BTC that they initially owned and build a Funding transaction. The input of this transaction is the BTC of each of them each; output is a condition for a 2-OF-2 multiple signature. At this time, the Funding transaction has not been signed by the two and has no broadcast. 2) Alice creates two transactions. The input of the first transaction spent a Funding transaction and handed it to the BOB for a good name (at this time Alice was not signed); the transaction contained 2 output structures, and the first output required the multiple of Alice and Bob's multiple Signature (Alice2 represents another private key of Alice), and the second output requires the signature of the BOB. The second transaction points to the first output of the first transaction. It is signed by BOB first, and its own output points to the address of Alice. This transaction has the conditions of Sequence, that is, it is required that the previous transaction must be confirmed that the transaction can be packed into the block. 3) Bob also created two transactions, and the transaction structure is completely symmetrical with the transaction created by Alice. 4) After completing the setting of the above transactions, the two parties signed the Funding transaction and broadcast them. The brief explanation: Funding transactions are to allow the two parties to take out a funds to establish a channel; the role of the later transaction is to allow the two parties to unilaterally request refund (Refund) funds. Both Alice and BOB have the right to unilaterally trigger Refund. However, whoever triggers Refund first, the other party can get Refund immediately, and you have to wait for the Sequence time to get Refund. As a result, both Alice and BOB can cancel channels and terminate cooperation at any time, and can ensure the security of both sides. 2.3 The balance in the payment channel is updated. It now the payment channel has been created. If Alice and BOB want to transfer each other, how should it be operated? During a transaction, the two parties jointly constructed another set of transactions to replace the original transaction and update the balance information in the transaction content. The question is here, the original transaction is still there, and both parties exchanged signatures. How can we abandon it? The method of solving is also very clever. When creating a new transaction, the signature requested by the sponsor is corresponding to a new private key (let alone Alice3, Bob3); at this time, Alice told Bob's original private key Alice2, BOB can modify the original transaction as one The new penalty transaction, the output of the transaction is itself, and cancel the Sequence restrictions; so that the BOB can be broadcast to implement the punishment in case Alice signed the transaction without permission, causing Alice to lose its own funds. Therefore, once Alice told BOB about Alice2, it is equivalent to announced that the original transaction was invalidated. Bob's side is also the same. The principle is really complicated, right? A simple and easy -to -understand conclusion is given: When the transaction balance needs to be updated, the two parties of the transaction can build new transactions to ensure that any of them can unilaterally tamper the balance of funds to make themselves profit. Mena, our doubts are completely solved. In the process of the construction, closure and balance changes of the payment channel, they can ensure that the two parties achieve the construction of related transactions without trust. Therefore, even the payment channel under the chain is completely trusted. 3. The node routing of the lightning network 3.1 Why does it need node routes The establishment of the payment channel to ensure that any two traders can establish a set of sets of transaction balance under the chain to recording transaction balance changes Accounts and realize trading behavior under the framework. , but there is still a problem that has not been resolved. We know that small payment behaviors are often high -frequency and the objects are not fixed, so does it mean that when any two individuals need to complete payment or transfer transactions, they must establish a payment channel between the two? Of course, it is impossible! As mentioned earlier, the establishment and closure of the payment channels are achieved through chain transactions. If users on Lightning Networks need to establish a payment channel with opponent Fang before paying payment, it is no different from trading directly on the chain. This is obviously ridiculous. In order to solve this problem, we need to build a routing mechanism between different payment channels. For example, assuming that Alice has established a payment channel with BOB, and BOB has established a payment channel with his friend Kevin. Now Alice wants to transfer KEVIN, then they can be intermediaries by BOB, through the path of Alice → Bob → Kevin to achieve payment behavior, no additional payment channels are required! 3.2 Payment channel route and HTLC transaction HTLC transaction full name has Hashed Time-Lock Contract, which means a contract locked in hash time. The simple understanding is that the contract is locked by a hash value and a expiration time parameter. I believe that everyone is tired of those extremely complicated technical explanations. The following is a simple example to illustrate the basic principles of HTLC. In the above example, we have found a routing path Alice → Bob → Kevin. We assume that Alice wants to pay 1BTC to Kevin. First of all, the BOB made a safe, stored in 1BTC, and handed it to Kevin; Alice also made a similar safe, deposited 1BTC and handed it over to Bob. The passwords of these two safe are the same, and they need to be provided by Kevin. When Kevin provides a password, this password will be publicized, which means that anyone can see this password. During the transaction execution, Kevin will open the safe sent by the Bob by providing a password to get 1BTC; BOB knows the password, open the safe sent by Alice to get 1BTC. It we noticed that Bob is equivalent to the intermediary in the transaction (ESCROW), and his existence enables Alice → Kevin's transactions. Therefore, theoretically BOB can collect certain commissions as a reward for matching Alice and Kevin. For example, BOB can put 0.99bTC in the safe to Kevin, leaving 0.01BTC as a commission for the transaction. Although our metaphors may not necessarily fully meet the actual situation, I believe it can also roughly explain the principle of HTLC. HTLC is also trusted. This means that we can support high -frequency small payment activities under the chain through a huge network built by countless RSMC and HTLC contracts, and we don't need to worry about the security of funds. 4. Lightning Network vs. LBTC: The dispute between the expansion method 4.1 Some evaluations of the lightning network have to say that the lightning network is a very genius and successful idea, at least it It is already on the way to large -scale implementation. At present, the Bitcoin community is closely concerned about the implementation of the Lightning Network, and the transactions inside the lightning network have a certain degree of activity. but the real large -scale application of the lightning network is a certain distance. I think there may be several problems in the lightning network, or at least it is worthy of attention: 1) Lightning networks have high requirements for infrastructure. Because the positioning of the Lightning Network is small high -frequency payment, there must be supporting equipment and software applications to support the algorithm required for Lightning Network. But if you observe the current situation, you will find that most of the wallets that can support the lightning network are still custody of wallets, not the real decentralized wallet. However, the real decentralized wallet distance is still far away by ordinary users. In this context, the significance of the Lightning Network has some doubts. 2) Lightning network as a payment facility under the chain, the requirements of the intermediary agencies and the transaction will be higher than the chain! Specifically, the intermediary agency needs to be operated online, and the two parties to the transaction can be provided to provide signatures to provide signatures. Construction of RSMC and HTLC transactions. Such a model has challenged the intermediary agency. The fragile and small intermediary agencies are bound to be difficult to survive. In contrast, the chain transaction does not have so many strict requirements for intermediaries and nodes; newly generated bitcoin transactions only need to be thrown into the P2P network, wait for the transaction to be packaged and produce a new block. You don’t need to worry about being too much. More problems. Although some shortcomings are mentioned, it is necessary to say that in actual use, the advantages of fast -to -account networks and low handling fees are existing. In addition, due to the characteristics of the settlement of the lightning network chain, it also has many side advantages such as transaction privacy protection.
The size of each block is one trillion, which can accommodate more than a thousand transactions. If you go to the Bitcoin blockchain browser to watch, you will find out that every block is about one trillion now about one trillion It has reached the upper limit of the block capacity. If there are more and more transfers of the Bitcoin network, many transactions will not be packaged and confirmed by the first block after the transaction. It may have to wait for several blocks or more time. In the history of Bitcoin, there have been several dust attacks. Among them, many traders create a large amount of small transfer on the exchange (currency exchange). The manufacture of a large amount of small transfer makes there a lot of transactions to be confirmed in the network, resulting in normal transfer of transfer, which cannot be confirmed. The confirmation time is delayed and affects the normal operation of the network.
The trading of many traders is waiting for two days or longer to be confirmed. Although the dust attack is a very extreme example, it is far exceeding the current Bitcoin network. The maximum capacity of each block is now a mega size, so it expands the capacity of Bitcoin block and breaks through the existing restrictions of a mega size. This process is called expansion.
What does expansion mean and why do you need to expand?
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1. The problem of expansion of Bitcoin
1.1 The TPS and the problem of the TPS and handling fees of Bitcoin transactions
The size of a bit currency block is 2m, and one block is produced every 10 minutes. Based on this, we can calculate the theory of Bitcoin:
TPS (BTC)
= block size / tx size / (10 * 60)
= 2 * 1024 * 1024 /500 / (10 * 60)
≈ 7
It, it can be seen that about 7 transactions of transactions can be dealt with in the average one second of Bitcoin. In addition, as the number of people using Bitcoin increases, Bitcoin transactions surge, which can easily cause Bitcoin transaction congestion. During congestion, the transaction forms a queue to wait for the upper chain, causing some trouble for users.
In addition, transaction congestion can also cause another serious consequences, that is, the transaction fee increases. Bitcoin transactions are packed by miners. Miners are paid by mining rewards and transaction fees. Therefore, miners have the motivation to increase transaction fees. Because users want a lower handling fee and miners hope to be higher, the market will form a balanced and reach the level of fees that you can accept. However, if the transaction is congested, the balance of supply and demand in the market will be broken, and the balance is inclined. Miners can require higher fees (theoretically, miners have the right to choose transactions that are prioritized and packaged).
The historical data (above: The vertical axis is a transaction fee for the US dollar pricing), and the Bitcoin single transaction fee has reached the pinnacle of $ 40 at the end of 2017, even within two months before and after Stable on a platform with $ 15-20. In non-active periods, trading fees can generally be maintained between $ 0.3-1.5.
Although the fees in the off -season seem to be acceptable, people cannot be satisfied with the status quo. After all, Bitcoin is a cryptocurrency that is hoped to move towards large -scale applications, and should have the ability to deal with large -scale transactions. Because of this, PROBLEM has become the defect of the most criticism.
1.2 Bitcoin's chain of the Bitcoin
We have mentioned in the previous article that Bitcoin's followers have realized the severity and urgency of Bitcoin's expansion problem. So how to expand capacity? This is the core link of controversy.
The first expansion idea is called on-chain expansion. The so -called chain expansion, as the name suggests, modify the parameters of the consensus agreement to achieve higher TPS data. For Bitcoin, increasing the time interval of blocks, increasing block capacity, and reducing the capacity of transactions are the theoretical feasible ideas. However, Bitcoin, as the largest cryptocurrency system today, can be described as the whole body, and has to be cautious. In fact, in order to prevent the degree of centralization from being lost due to the high threshold of the whole node, Bitcoin is almost impossible to shorten the time interval. As a result, the possibility is compressed to block capacity and transaction capacity.
It in terms of transaction capacity occupation, the framework of Bitcoin has determined the format and content of the transaction, which can reduce the room for reduction. After the segwit is upgraded, the structure of the transaction has been optimized, but the changes in this area must be very limited.
We we have to turn our eyes to the size of the block. Because the initial agreement of the Bitcoin agrees with a capacity of 1M, and at the moment when the Internet infrastructure is developed at the rapid development, this does not seem to constitute any pressure. Some supporters have proposed that the capacity restrictions and increase the capacity limit. In fact, a bifurcation protocol of Bitcoin-Bitcoin Cash (BCH) did this: BCH directly increased the block capacity to 32M, and threatened to continue to increase significantly in the future. After the Bitcoin is also an isolated testimony, it has obtained nearly 2M block capacity.
, but the idea of expanding capacity is questionable: the reason is that the income expansion is limited, but the damage to the decentralization is great.
We can make a simple comparison:
· Bitcoin cash (BCH) to increase the size to 32M, which can achieve a 16 -fold TPS increase compared to Bitcoin (BTC);
· Lightning Bitcoin (LBTC) can achieve an increase of 200 times compared to Bitcoin (BTC) by DPOS based on UTXO.
However, increased the volume of the block, which will greatly increase the threshold of the whole node, and the efficiency and speed of the block circulation in the P2P network. This is a problem of worrying about Bitcoin's original teachings. Because of this, Bitcoin (BTC) is extremely cautious in improving block capacity and is always unwilling to let go of restrictions.
1.3 Another idea
If the income of expansion on the chain is limited and the potential damage is great, can it be turned to the expansion idea of the non -chain?
The answer is okay. The expansion on the non-chain can be solved by the idea of off-chain or cross-chain.
The first talk about cross -chain. Cross -chain refers to the substantial higher TPS by binding the Bitcoin network to a higher TPS blockchain. But this requires a recognized cross -chain technical solution, and the Child Chain ecosystem. This approach seems embarrassing because we must introduce a new blockchain.
The expansion of the chain is the most concerned and high -feasibility solution that people are most concerned about. The famous Lightning Network is such a chain expansion solution.
The meaning of expansion under the chain means that the transaction is reached under the chain and does not occupy the resources on the chain; when a series of transactions are reached, the final result conveys the chain. Understand, you can see that there is a small bank to help you complete a series of transfer transactions, and then send the balance data to the chain regularly.
It in the following, we will specifically describe the operating mechanism of the Lightning Network and evaluate whether this expansion method is really effective.
2. The basic operation principle of the lightning network
2.1 Payment channel
Matons will have some questions after exposed to the lightning network, for example: Since the lightning network is a transaction under the chain, why are we Can I trust it?
This is a good question! If you ask this question, at least it shows that you have a certain understanding of the blockchain. The Lightning Network does complete the transaction under the chain, but I can guarantee that its operating mechanism is very reliable. Lightning network depends on some safe solutions in column passwords to complete the establishment of payment channel establishment, payment and balance change, and even node routing.
It we here is a new term: payment channel. The payment channel sounds abstract, but you can understand this: it is a account that opens between two traders, which are maintained by two traders. When a transaction occurs, the transaction will be recorded in this account. After a period of time and several trading, the balance of the account will be registered on the Bitcoin chain.
The lightning network is a network of payment channels. Except for the creation and closing of the payment channel, the other operations are under the chain transaction, and the rest of the operation is under the chain. Based on this, the lightning network realizes a good chain expansion, which has greatly extended the trading potential of Bitcoin.
2.2 Payment channels and RSMC transactions
The opening, closing, and balance of the payment channel are achieved through a type of transaction type called RSMC.
RSMC's full name is Revocable Sequence Maturity Contract, which means that the sequence expires can be revoked, which is composed of a series of transactions to implement specific functions.
The us take the payment channel between Alice and BOB to transfer each other and build the payment channel between the two people. Try to simply explain the establishment of the payment channel.
The construction steps of the entire channel are as follows:
1) Alice and BOB each take out the BTC that they initially owned and build a Funding transaction. The input of this transaction is the BTC of each of them each; output is a condition for a 2-OF-2 multiple signature. At this time, the Funding transaction has not been signed by the two and has no broadcast.
2) Alice creates two transactions.
The input of the first transaction spent a Funding transaction and handed it to the BOB for a good name (at this time Alice was not signed); the transaction contained 2 output structures, and the first output required the multiple of Alice and Bob's multiple Signature (Alice2 represents another private key of Alice), and the second output requires the signature of the BOB.
The second transaction points to the first output of the first transaction. It is signed by BOB first, and its own output points to the address of Alice. This transaction has the conditions of Sequence, that is, it is required that the previous transaction must be confirmed that the transaction can be packed into the block.
3) Bob also created two transactions, and the transaction structure is completely symmetrical with the transaction created by Alice.
4) After completing the setting of the above transactions, the two parties signed the Funding transaction and broadcast them.
The brief explanation:
Funding transactions are to allow the two parties to take out a funds to establish a channel; the role of the later transaction is to allow the two parties to unilaterally request refund (Refund) funds. Both Alice and BOB have the right to unilaterally trigger Refund. However, whoever triggers Refund first, the other party can get Refund immediately, and you have to wait for the Sequence time to get Refund. As a result, both Alice and BOB can cancel channels and terminate cooperation at any time, and can ensure the security of both sides.
2.3 The balance in the payment channel is updated.
It now the payment channel has been created. If Alice and BOB want to transfer each other, how should it be operated? During a transaction, the two parties jointly constructed another set of transactions to replace the original transaction and update the balance information in the transaction content.
The question is here, the original transaction is still there, and both parties exchanged signatures. How can we abandon it?
The method of solving is also very clever. When creating a new transaction, the signature requested by the sponsor is corresponding to a new private key (let alone Alice3, Bob3); at this time, Alice told Bob's original private key Alice2, BOB can modify the original transaction as one The new penalty transaction, the output of the transaction is itself, and cancel the Sequence restrictions; so that the BOB can be broadcast to implement the punishment in case Alice signed the transaction without permission, causing Alice to lose its own funds. Therefore, once Alice told BOB about Alice2, it is equivalent to announced that the original transaction was invalidated. Bob's side is also the same.
The principle is really complicated, right? A simple and easy -to -understand conclusion is given: When the transaction balance needs to be updated, the two parties of the transaction can build new transactions to ensure that any of them can unilaterally tamper the balance of funds to make themselves profit.
Mena, our doubts are completely solved. In the process of the construction, closure and balance changes of the payment channel, they can ensure that the two parties achieve the construction of related transactions without trust. Therefore, even the payment channel under the chain is completely trusted.
3. The node routing of the lightning network
3.1 Why does it need node routes
The establishment of the payment channel to ensure that any two traders can establish a set of sets of transaction balance under the chain to recording transaction balance changes Accounts and realize trading behavior under the framework.
, but there is still a problem that has not been resolved. We know that small payment behaviors are often high -frequency and the objects are not fixed, so does it mean that when any two individuals need to complete payment or transfer transactions, they must establish a payment channel between the two? Of course, it is impossible! As mentioned earlier, the establishment and closure of the payment channels are achieved through chain transactions. If users on Lightning Networks need to establish a payment channel with opponent Fang before paying payment, it is no different from trading directly on the chain. This is obviously ridiculous.
In order to solve this problem, we need to build a routing mechanism between different payment channels.
For example, assuming that Alice has established a payment channel with BOB, and BOB has established a payment channel with his friend Kevin. Now Alice wants to transfer KEVIN, then they can be intermediaries by BOB, through the path of Alice → Bob → Kevin to achieve payment behavior, no additional payment channels are required!
3.2 Payment channel route and HTLC transaction
HTLC transaction full name has Hashed Time-Lock Contract, which means a contract locked in hash time. The simple understanding is that the contract is locked by a hash value and a expiration time parameter.
I believe that everyone is tired of those extremely complicated technical explanations. The following is a simple example to illustrate the basic principles of HTLC.
In the above example, we have found a routing path Alice → Bob → Kevin. We assume that Alice wants to pay 1BTC to Kevin.
First of all, the BOB made a safe, stored in 1BTC, and handed it to Kevin; Alice also made a similar safe, deposited 1BTC and handed it over to Bob. The passwords of these two safe are the same, and they need to be provided by Kevin. When Kevin provides a password, this password will be publicized, which means that anyone can see this password.
During the transaction execution, Kevin will open the safe sent by the Bob by providing a password to get 1BTC; BOB knows the password, open the safe sent by Alice to get 1BTC.
It we noticed that Bob is equivalent to the intermediary in the transaction (ESCROW), and his existence enables Alice → Kevin's transactions. Therefore, theoretically BOB can collect certain commissions as a reward for matching Alice and Kevin. For example, BOB can put 0.99bTC in the safe to Kevin, leaving 0.01BTC as a commission for the transaction.
Although our metaphors may not necessarily fully meet the actual situation, I believe it can also roughly explain the principle of HTLC. HTLC is also trusted. This means that we can support high -frequency small payment activities under the chain through a huge network built by countless RSMC and HTLC contracts, and we don't need to worry about the security of funds.
4. Lightning Network vs. LBTC: The dispute between the expansion method
4.1 Some evaluations of the lightning network
have to say that the lightning network is a very genius and successful idea, at least it It is already on the way to large -scale implementation. At present, the Bitcoin community is closely concerned about the implementation of the Lightning Network, and the transactions inside the lightning network have a certain degree of activity.
but the real large -scale application of the lightning network is a certain distance. I think there may be several problems in the lightning network, or at least it is worthy of attention:
1) Lightning networks have high requirements for infrastructure. Because the positioning of the Lightning Network is small high -frequency payment, there must be supporting equipment and software applications to support the algorithm required for Lightning Network. But if you observe the current situation, you will find that most of the wallets that can support the lightning network are still custody of wallets, not the real decentralized wallet. However, the real decentralized wallet distance is still far away by ordinary users. In this context, the significance of the Lightning Network has some doubts.
2) Lightning network as a payment facility under the chain, the requirements of the intermediary agencies and the transaction will be higher than the chain! Specifically, the intermediary agency needs to be operated online, and the two parties to the transaction can be provided to provide signatures to provide signatures. Construction of RSMC and HTLC transactions. Such a model has challenged the intermediary agency. The fragile and small intermediary agencies are bound to be difficult to survive. In contrast, the chain transaction does not have so many strict requirements for intermediaries and nodes; newly generated bitcoin transactions only need to be thrown into the P2P network, wait for the transaction to be packaged and produce a new block. You don’t need to worry about being too much. More problems.
Although some shortcomings are mentioned, it is necessary to say that in actual use, the advantages of fast -to -account networks and low handling fees are existing. In addition, due to the characteristics of the settlement of the lightning network chain, it also has many side advantages such as transaction privacy protection.
The us take the payment channel between Alice and BOB to transfer each other and build the payment channel between the two people. Try to simply explain the establishment of the payment channel.
The construction steps of the entire channel are as follows:
1) Alice and BOB each take out the BTC that they initially owned and build a Funding transaction. The input of this transaction is the BTC of each of them each; output is a condition for a 2-OF-2 multiple signature. At this time, the Funding transaction has not been signed by the two and has no broadcast.
2) Alice creates two transactions.
The input of the first transaction spent a Funding transaction and handed it to the BOB for a good name (at this time Alice was not signed); the transaction contained 2 output structures, and the first output required the multiple of Alice and Bob's multiple Signature (Alice2 represents another private key of Alice), and the second output requires the signature of the BOB.
The second transaction points to the first output of the first transaction. It is signed by BOB first, and its own output points to the address of Alice. This transaction has the conditions of Sequence, that is, it is required that the previous transaction must be confirmed that the transaction can be packed into the block.
3) Bob also created two transactions, and the transaction structure is completely symmetrical with the transaction created by Alice.
4) After completing the setting of the above transactions, the two parties signed the Funding transaction and broadcast them.
The brief explanation:
Funding transactions are to allow the two parties to take out a funds to establish a channel; the role of the later transaction is to allow the two parties to unilaterally request refund (Refund) funds. Both Alice and BOB have the right to unilaterally trigger Refund. However, whoever triggers Refund first, the other party can get Refund immediately, and you have to wait for the Sequence time to get Refund. As a result, both Alice and BOB can cancel channels and terminate cooperation at any time, and can ensure the security of both sides.
2.3 The balance in the payment channel is updated.
It now the payment channel has been created. If Alice and BOB want to transfer each other, how should it be operated? During a transaction, the two parties jointly constructed another set of transactions to replace the original transaction and update the balance information in the transaction content.
The question is here, the original transaction is still there, and both parties exchanged signatures. How can we abandon it?
The method of solving is also very clever. When creating a new transaction, the signature requested by the sponsor is corresponding to a new private key (let alone Alice3, Bob3); at this time, Alice told Bob's original private key Alice2, BOB can modify the original transaction as one The new penalty transaction, the output of the transaction is itself, and cancel the Sequence restrictions; so that the BOB can be broadcast to implement the punishment in case Alice signed the transaction without permission, causing Alice to lose its own funds. Therefore, once Alice told BOB about Alice2, it is equivalent to announced that the original transaction was invalidated. Bob's side is also the same.
The principle is really complicated, right? A simple and easy -to -understand conclusion is given: When the transaction balance needs to be updated, the two parties of the transaction can build new transactions to ensure that any of them can unilaterally tamper the balance of funds to make themselves profit.
Mena, our doubts are completely solved. In the process of the construction, closure and balance changes of the payment channel, they can ensure that the two parties achieve the construction of related transactions without trust. Therefore, even the payment channel under the chain is completely trusted.
3. The node routing of the lightning network
3.1 Why does it need node routes
The establishment of the payment channel to ensure that any two traders can establish a set of sets of transaction balance under the chain to recording transaction balance changes Accounts and realize trading behavior under the framework.
, but there is still a problem that has not been resolved. We know that small payment behaviors are often high -frequency and the objects are not fixed, so does it mean that when any two individuals need to complete payment or transfer transactions, they must establish a payment channel between the two? Of course, it is impossible! As mentioned earlier, the establishment and closure of the payment channels are achieved through chain transactions. If users on Lightning Networks need to establish a payment channel with opponent Fang before paying payment, it is no different from trading directly on the chain. This is obviously ridiculous.
In order to solve this problem, we need to build a routing mechanism between different payment channels.
For example, assuming that Alice has established a payment channel with BOB, and BOB has established a payment channel with his friend Kevin. Now Alice wants to transfer KEVIN, then they can be intermediaries by BOB, through the path of Alice → Bob → Kevin to achieve payment behavior, no additional payment channels are required!
3.2 Payment channel route and HTLC transaction
HTLC transaction full name has Hashed Time-Lock Contract, which means a contract locked in hash time. The simple understanding is that the contract is locked by a hash value and a expiration time parameter.
I believe that everyone is tired of those extremely complicated technical explanations. The following is a simple example to illustrate the basic principles of HTLC.
In the above example, we have found a routing path Alice → Bob → Kevin. We assume that Alice wants to pay 1BTC to Kevin.
First of all, the BOB made a safe, stored in 1BTC, and handed it to Kevin; Alice also made a similar safe, deposited 1BTC and handed it over to Bob. The passwords of these two safe are the same, and they need to be provided by Kevin. When Kevin provides a password, this password will be publicized, which means that anyone can see this password.
During the transaction execution, Kevin will open the safe sent by the Bob by providing a password to get 1BTC; BOB knows the password, open the safe sent by Alice to get 1BTC.
It we noticed that Bob is equivalent to the intermediary in the transaction (ESCROW), and his existence enables Alice → Kevin's transactions. Therefore, theoretically BOB can collect certain commissions as a reward for matching Alice and Kevin. For example, BOB can put 0.99bTC in the safe to Kevin, leaving 0.01BTC as a commission for the transaction.
Although our metaphors may not necessarily fully meet the actual situation, I believe it can also roughly explain the principle of HTLC. HTLC is also trusted. This means that we can support high -frequency small payment activities under the chain through a huge network built by countless RSMC and HTLC contracts, and we don't need to worry about the security of funds.
4. Lightning Network vs. LBTC: The dispute between the expansion method
4.1 Some evaluations of the lightning network
have to say that the lightning network is a very genius and successful idea, at least it It is already on the way to large -scale implementation. At present, the Bitcoin community is closely concerned about the implementation of the Lightning Network, and the transactions inside the lightning network have a certain degree of activity.
but the real large -scale application of the lightning network is a certain distance. I think there may be several problems in the lightning network, or at least it is worthy of attention:
1) Lightning networks have high requirements for infrastructure. Because the positioning of the Lightning Network is small high -frequency payment, there must be supporting equipment and software applications to support the algorithm required for Lightning Network. But if you observe the current situation, you will find that most of the wallets that can support the lightning network are still custody of wallets, not the real decentralized wallet. However, the real decentralized wallet distance is still far away by ordinary users. In this context, the significance of the Lightning Network has some doubts.
2) Lightning network as a payment facility under the chain, the requirements of the intermediary agencies and the transaction will be higher than the chain! Specifically, the intermediary agency needs to be operated online, and the two parties to the transaction can be provided to provide signatures to provide signatures. Construction of RSMC and HTLC transactions. Such a model has challenged the intermediary agency. The fragile and small intermediary agencies are bound to be difficult to survive. In contrast, the chain transaction does not have so many strict requirements for intermediaries and nodes; newly generated bitcoin transactions only need to be thrown into the P2P network, wait for the transaction to be packaged and produce a new block. You don’t need to worry about being too much. More problems.
Although some shortcomings are mentioned, it is necessary to say that in actual use, the advantages of fast -to -account networks and low handling fees are existing. In addition, due to the characteristics of the settlement of the lightning network chain, it also has many side advantages such as transaction privacy protection.