JP7290299B2 - Blockchain system and computer program that suppresses fluctuations in coin value and prevents crashes - Google Patents

Description

The present invention suppresses fluctuations in the legal currency-denominated price of coins issued in a blockchain system, while at the same time realizing a mechanism that naturally restores the value of coins when the value of the coins declines. Mechanism for limiting the number of coins issued in a blockchain system that can handle coins, and crypto assets realized by it.

First, the definitions of terms used in this specification are described.
Crypto assets are property values that can be exchanged on the Internet. By using blockchain, crypto assets can be exchanged without going through a third party such as a bank.
An exchange refers to a business that exchanges crypto assets and fiat currencies.
A blockchain system is a computer system that realizes a blockchain, consisting of all computers that run software such as miners and wallets.
A user is a person who uses the blockchain system.
An account is equivalent to a bank account, and refers to the data recorded on the blockchain for managing the crypto assets owned by each user on the blockchain system. Contains the user's public key.
An oracle is a service that sends information outside the blockchain system to nodes within the blockchain system.
A consensus algorithm is an algorithm for forming an agreement on the correct transaction results among a large number of nodes that make up a blockchain system. In addition to proof of work used in Bitcoin, proof of stake etc. are used.
A node is a computer connected to a network.
A peer-to-peer network is a distributed computer system architecture characterized by multiple computers connected by a network communicating on an equal footing.
Broadcasting means transmitting information so that it reaches all computers connected to the network.
A gossip protocol is a technique for repeatedly and stochastically exchanging information between computers connected to a network.
Topology indicates which computer is directly connected to each computer connected to the network to exchange information. In order to communicate between computers that are not directly connected, it is necessary to have the directly connected computer relay the data.
A thread is a sequence of instructions that are executed continuously on a computer that can process multiple things in parallel.
A hash value is fixed-length data generated for arbitrary data, and while the calculation time required to generate a hash value from arbitrary data is short, it is difficult to find the corresponding data from the hash value. , it is practically impossible because it requires an extremely long computation time.
Electronic signature. Each user generates in advance a pair of data called a public key and a private key, publicly discloses the public key, and keeps the private key without telling anyone. A user generates and attaches data called an electronic signature to arbitrary data using a secret key. For arbitrary data, a digital signature can only be generated using a private key. A person who receives data with an electronic signature can confirm that the electronic signature was generated by a user corresponding to the public key by using the public key for the electronic signature.

Since the advent of Bitcoin (Non-Patent Document 1), many crypto assets using blockchain have been developed. Transactions using crypto-assets are increasing year by year, and the market capitalization of crypto-assets exceeded $1 trillion in early 2021.

Bitcoin is a fully decentralized crypto asset that allows users to exchange coins without the need for a specific node such as a central bank.
The history of all transactions in cryptocurrencies is stored on the blockchain. Blockchain is data in a list structure, and it is designed so that new data can be added one after another, making it difficult to modify data that has been registered in the past. A large number of blocks can be stored in a blockchain as a linked list, and all information registered in the blockchain is open to the public. Each block contains multiple items and the hash value of the previous block. Part of the item is transaction data, representing cryptocurrency transactions. A user node intending to make a transaction electronically signs an item containing transaction data representing the details of the transaction and broadcasts it to the network. Only items whose signatures are genuine and whose transaction data are consistent and executable will be accepted and recorded on the blockchain. The latest state of each user's account is defined as the result of executing all the transactions represented by the transaction data recorded in each block included in the blockchain, starting from the initial state of the account.
In Bitcoin, a mechanism called Proof of Work (PoW) determines the correct result of transactions recorded in the blockchain, preventing double spending of coins. It is easy to secure a large number of IP addresses in a network, and a majority rule that gives voting rights to each IP address does not work well. PoW is used in such an environment to implement a majority vote in which voting power is given according to the amount of computation. Each block has an entry that stores an integer value called a nonce, and the hash value of the block has a fixed number of nonces starting with zero bits, and all transactions included in the block can be executed without contradiction. Only such blocks are accepted as valid blocks. Verifying that each transaction contained in a block is consistently executable is called verification. In PoW, transaction data broadcast by user nodes is collected by nodes participating in the network, and a new block containing transaction data that has been successfully verified is constructed so that the hash value of the new block starts with a fixed number of zero bits. looking for a nonce. When a node finds such a nonce, it broadcasts a new block containing the found nonce onto the network, and other nodes that receive this block verify this block, and if successful, create a new block after this one. try to add

To maintain the network, newly minted coins are awarded as an incentive to nodes that successfully add new blocks. New coins are issued every time a new block is added. All coins circulating on the Bitcoin system are issued in this way and stored in the accounts of users of the system. A node that tries to add a block is called a miner. Block mining is the process of searching for a nonce whose hash value of a new block starts with a fixed number of zero bits, and adding a new block containing the found nonce to the blockchain. A bona fide miner will attempt to add blocks to the longest blockchain known to that node. The time it takes for each block to be added is called the block time. The number of zero bits in the hash value is automatically adjusted so that the expected block time is 10 minutes.

As long as most of the CPU resources are used by well-intentioned miners to add blocks, the blockchains that record correct transactions grow the fastest. A majority vote in which voting rights are given according to the amount of calculation is realized in this way. This kind of mechanism makes it difficult to forge or falsify information recorded in the blockchain. the attack is unsuccessful.

To ensure that miners have an incentive to include as many items as possible in blocks that are added, when user nodes broadcast items, they pay a fee, called a transaction fee, included in the item. When a block is added to the blockchain, the transaction fee for all items contained in that block is paid to the miner who added the block. There is an upper limit to the size of one block, and when there are more items than can fit in a block, miners decide the combination of items to be included in the block so that the transaction fee obtained by adding a block is maximized. can be done. By paying a large transaction fee for an item, a user node increases the likelihood that the item will be registered on the blockchain sooner.

The legal tender issued by the central bank of each country is issued by the monetary authority and is widely used in the business world to maintain its value. In the past, the gold standard system was adopted, and under this system, the government guaranteed the value of the currency by exchanging it for the same amount of gold. In order for a currency to exist as a currency, it is said that the six properties of rarity, divisibility, acceptability, portability, durability, and resistance to counterfeiting must hold. Corroboration is not always required. Crypto-assets have these six properties and can therefore be used as currencies.

One of the problems with crypto-assets such as Bitcoin is the large price fluctuations. In order for crypto-assets to be used for settlement with peace of mind, it is desirable that price fluctuations relative to legal currencies are small. On the other hand, there are also users who want to use crypto assets for speculation purposes. Small price fluctuations are not necessarily good for speculative users, and simply suppressing price fluctuations does not necessarily contribute to the spread of crypto-assets.

Efforts have been made to curb the price volatility of crypto-assets. A crypto asset designed to maintain a constant price, or peg, to a specific fiat currency is called a stablecoin. Below, we will discuss Tether and Dai, Empty Set Dollar and Terra, which are representative stablecoins designed to maintain the value of 1 US dollar (hereinafter referred to as 1 US dollar).

Tether (NPL 2) is designed to maintain the value of US$1. When a user buys Tether, the money goes into Tether's reserve. The reserve holds US dollars equal to the total amount of Tether purchased by all users. When a user sells Tether and earns a substantial amount of US dollars, US dollars are paid out of this reserve. Tether purchased by users can be traded on the network like other crypto assets. Tether requires a US dollar legal tender reserve equal to the amount issued. Moreover, it cannot be realized by perfect dispersion.

Dai (Non-Patent Document 3) is a smart contract enabled stablecoin on Ethereum (Non-Patent Document 4) designed to maintain a price of US$1. Users can borrow newly generated Dai by depositing Ether as collateral. The minimum collateral rate is currently set at 150%. For example, if you deposit $150 worth of Ether, you can borrow up to about $100 worth of Dai. Once you repay the Dai you borrowed and the interest on it, you can withdraw the Ether that you deposited as collateral. If the collateral amount falls below the minimum collateral rate, the collateral Ether will be sold and the amount equal to the borrowed Dai plus a penalty will be deducted from this. An amount of Ether that always exceeds the total amount of issued Dai is deposited as collateral, and the value of Dai is backed by the value of collateral Ether. In order to borrow Dai, collateral in Ether is required, and the amount of this collateral is 150% or more of the amount of Dai to be issued. Moreover, it cannot be realized by perfect dispersion.

Empty Set Dollar (ESD) (Non-Patent Document 5) is designed to maintain the value of the US dollar through a purely algorithmic approach. When the price of ESD is above US$1, issuing more ESD will lower the price of ESD. Debt coupons will be issued if the price of ESD drops below US$1. Debt coupons can be exchanged for ESD the next time the price of ESD rises above US$1, and the more debt coupons you buy, the more ESD you can exchange for. When the price of ESD drops below US$1, users purchase debt coupons to reduce the amount of ESD in circulation and increase the price of ESD. The problem with ESD is that there is no guarantee that the debt coupon will be redeemed, and in principle a crash in price could occur.

Terra [6] is designed to preserve the value of the US dollar in a purely algorithmic manner. Terra is traded on the same blockchain system as its companion coin, Luna, and Terra's value is backed by Luna. Users can mine Luna on the blockchain system, and Luna has the role of absorbing the fluctuations in Terra's value. Users can exchange Terra and Luna using the functionality of the blockchain system. If Terra rises above US$1, the exchange rate will be set so that users will exchange more Luna for Terra. This will supply more Terra, lower the value of Terra, and increase the value of Luna. Conversely, if Terra falls below US$1, the exchange rate will be set so that users will trade Terra for Luna. With more users exchanging Terra for Luna and Terra's circulation decreasing, Terra's value increases and Luna's value decreases. Luna is issued through mining and exchange from Terra, and depending on changes in the exchange rate, the circulation of Luna may exceed the total amount of Luna mined. If Terra/Luna trades at a faster speed than the mechanism that stabilizes Terra's value can operate, the value of both crypto-assets may fluctuate significantly.

Exchanges hold a certain amount of crypto assets such as Terra. When a user sells Terra on an exchange, the amount of Terra held by the exchange increases. To correct this balance, exchanges sell their Terra holdings to other users at a discount.
From April to May 2022, the values of Terra and Luna plummeted at the same time (Non-Patent Document 7). The crash of Terra and Luna traced the following course (Non-Patent Documents 8 and 9). [3, 4].
1. The observation that the value of Terra will fall among users has spread.
2. The value of Terra fell slightly below US$1 due to natural fluctuations.
3. Users flooded exchanges to exchange Terra for other stablecoins such as Tether.
4. Due to the large number of users trying to sell their Terras, the exchange was unable to sell their Terras and stopped trading Terras.
5. Many users tried to turn Terra into Luna.
6. Luna's value plummeted as a large number of Terras were exchanged for Luna.
7. Due to the large number of transactions in a short time, there was a delay in transactions on the blockchain system. Terra's value remained below US$1 and did not recover.
8. Terra's value fell further, and Luna's value did not recover.

If many users try to exchange Terra for Luna when the value of Terra falls below 1 USD, Luna will be issued in large quantities in a short period of time, and Luna will be valued before Terra restores the value of 1 USD. is likely to plummet. Also, in general, if too much currency is issued, the value of the currency will fall and inflation will occur. This applies not only to crypto assets but also to fiat currencies. An effective way to prevent currency depreciation is to reduce the amount of currency in circulation by restricting the issuance of currency and collecting currency in circulation. Terra/Luna does not have a mechanism to prevent a large amount of Luna from being issued in the above situation.

The system described in US 20200202311 A1 (Patent Document 1) can handle two types of coins: utility tokens and reserve tokens. Only utility tokens can be used by users for trading, and when the value of a coin drops below US$1, a certain percentage of coins mined and traded will be collected as reserve tokens. As the circulation of coins decreases, the value of coins recovers. If the value of the coin rises above US$1, the reserve tokens will be added to the mining reward and paid out to the miners. There is no mechanism for users to exchange utility tokens and reserve tokens. It is a mechanism that forcibly collects a certain percentage of the coins owned by the user when the value of the coins declines, and there is a possibility that the users will not accept it. In addition, there is a need for a mechanism to monitor the transaction price of coins in legal currency, and although the specification describes this as an oracle, the system must be designed on the premise that the oracle will operate correctly.

The method described in US 20200042988 A1 (Patent Document 2) broadly covers systems that provide means for exchanging two types of crypto assets on the system. In this method, one of the two types of cryptographic assets is pegged to the market price of assets traded outside the blockchain system. ing. It is difficult to implement such a mechanism for monitoring market prices without assuming that some nodes on the network are operating correctly. This method has the same problems as Terra/Luna.

US 20200202311 A1 US 20200042988 A1 Patent No. 6811504

Nakamoto, S. : Bitcoin: A Peer-to-Peer Electronic Cash System (2008). “Tether: Fiat currencies on the Bitcoin blockchain,” [Online] available: https://assets.ctfassets.net/vyse88cgwfbl/5UWgHMvz071t2Cq5yTw5vi/c9798ea8db99311bf90ebe0810938b01/TetherWhitePaper.pdf. The Maker Team, “The Dai Stablecoin System,” Accessed: Dec.6, 2022, [Online] available: https://makerdao.com/whitepaper/DaiDec17WP.pdf. Buterin, Vitalik. "A next-generation smart contract and decentralized application platform." white paper 3, no. 37 (2014): 2-1. Lewis Freiberg, “Empty Set Dollar (ESD),” Accessed: Dec.6, 2022, [Online] available: https://medium.com/@lewisfreiberg/empty-set-dollar-esd-a0abbfc5ecdb Evan Kereiats, Do Kwon, Marco Di Maggio, and Nicholas Platias, “TERRA Money: Stability and Adoption,“ Accessed Dec.6, 2022, [Online] Avairable] Available: HTT ps: //assets.website-files.com/61153e7AF981472DA19c/618b02D13E938AE1F8AD1E45_white_white_paper .pdf, 2019. Jeff John Roberts, “7 Big Moments From Bitcoin and Crypto's Craziest Week Ever,” Accessed Nov.12, 2022, [Online] available: https://decrypt.co/100358/7-big-moments-from-bitcoin-crypto -crash, 2022. Liam J. Kelly, “How Terra's UST and LUNA Imploded,” Accessed Nov.12, 2022, [Online] available: https://decrypt.co/100402/how-terra-ust-luna-imploded-crypto-crash, 2022. Chainalysis Team, “The Trades That Triggered TerraUSD’s Collapse,” Accessed Nov.12, 2022, [Online] available: https://blog.chainalysis.com/reports/how-terrausd-collapsed/, 2022. Tim Copeland, “Billions of Luna minted as supply grows 20-fold in four days,” Accessed: Nov. 12, 2022, [Online] available: https://www.theblock.co/post/146532/billions-of- luna-minted-as-supply-grows-20-fold-in-four-days, 2022. Naoki Shibata, "Proof-of-Search: Combining Blockchain Consensus Formation With Solving Optimization Problems," in IEEE Access, vol. 7, pp. 172994-173006, 2019, doi: 10.1109/ACCESS.2019.2956698.

The problem to be solved by the present invention is to provide a blockchain system that implements both a mechanism for suppressing price fluctuations of coins against legal currency and a mechanism for preventing a plunge in the value of coins.

One of the factors behind the simultaneous crash of Terra and Luna is the mechanism on the blockchain system that allows unlimited exchange from Terra to Luna. Since there was no mechanism to limit the distribution of Luna, a large number of Luna were issued in a short period of time, resulting in a sharp decline in the value of Luna (Non-Patent Document 10). If there was no mechanism for unlimited exchange of Terra to Luna, even if Terra crashed, Luna would not have crashed due to it. It is possible to greatly reduce the risk of a simultaneous decline in the value of The problem in this case is how to realize a means of recovering this if Terra's value declines.

In the present invention, as with Terra/Luna, a single blockchain allows transactions of multiple types of coins. Below, we will explain an example of enabling trading of two types of crypto assets called High Volatility Coin (HV coin) and Low Volatility Coin (LV coin) (Fig. 1). HV coin is equivalent to Luna and is assumed to be used for speculation. There is no problem even if the price fluctuation of HV coin is large. In addition, it is desirable that the value tends to rise in the long term. LV coin is equivalent to Terra and is assumed to be used for settlement. It is desirable that the price fluctuation of LV coin is as small as possible. Luna is mined using a consensus algorithm called Proof of Stake, but like Luna, HV coins are also mined by users using some kind of consensus algorithm.
LV coins cannot be directly mined by users, and the system provides a mechanism for exchanging HV coins owned by users for LV coins at an exchange rate determined by the system. The exchange rate from HV coin to LV coin is set as close as possible to the exchange rate of HV coin to legal currency. This will be discussed later. When HV coins are exchanged for LV coins, the circulation of HV coins decreases and the circulation of LV coins increases.

In the present invention, restrictions are placed on the exchange of coins. In the above example, there are multiple ways to restrict, but the simplest example is to completely prohibit the exchange of LV coins for HV coins. In this case, in order for users to exchange LV coins for HV coins, it is necessary to trade between users personally or go through an exchange. Since there is no mechanism to exchange LV coins for HV coins, the circulation of HV coins will never exceed the total amount of HV coins mined so far. The circulation of HV coins is the total number of HV coins mined so far minus the number of LV coins exchanged. , so the value of HV coin will not be affected. If PoW is used as a consensus algorithm for HV coin in the same way as bitcoin, HVcoin is as or more resistant to depreciation as bitcoin.
If the above method prohibits the exchange of LV coins for HV coins at all, it will take time to recover if the value of LV coins drops. The aim of the present invention is to prevent unlimited issuance of HV coins exceeding the total amount of mined HV coins. Below, we describe an example of how to prevent the unlimited issuance of HV coins by controlling the exchange rate while allowing the exchange of LV coins for HV coins within a certain range.

Let M, H, and L be the number of HV coins mined so far, and the number of HV and LV coins currently in circulation. Let X be the reciprocal of the current exchange rate from HV coins to LV coins, that is, exchange X HV coins for one LV coin. Since the LV coins currently in circulation can be considered to have been exchanged from a total of (M-H) HV coins, each LV coin was exchanged from (M-H)/L HV coins. Let MIN be the function that returns the minimum value of the given arguments. Y=MIN((M-H)/L, X) is the exchange rate from LV coins to HV coins, i.e., when exchanging 1 LV coin for Y HV coins, the circulation of HV coins never exceeds M. . In this example, if the exchange rate becomes negative, the system stops exchanging LV coins to HV coins.

From the viewpoint of preventing unlimited issuance of HV coins, it is not necessary to keep the circulation of HV coins below M. Therefore, instead of setting the upper limit of the circulation amount of HV coins to M, an appropriate function F may be defined in the system, and the upper limit of the circulation amount of HV coins may be generalized as F(M). Combined with the above example, MIN((F(M)-H)/L, X) is the exchange rate from LV coins to HV coins. In this way, as a result of exchanging LV coins for HV coins by the system, the circulation of HV coins will not exceed F(M). By making F(M) larger than M, the exchange rate from LV coins to HV coins by the system becomes more attractive to users, and the frequency of system stoppages is reduced. . The above example of a method of completely prohibiting the exchange of LV coins for HV coins is equivalent to giving a function of F(M)=0, and an example of a method of suppressing the circulation of HV coins below M is F( M)=M is equivalent to giving a function.

When setting the exchange rate, an exchange fee may be collected from the exchange rate determined in this manner. For example, if the exchange fee is 1%, MIN((F(M)-H)/L, (1-0.01)X) is the exchange rate from LV coins to HV coins. In addition to the methods described above, various other methods are conceivable for limiting the circulation of HV coins.
When the value of LV coins is lower than the exchange rate of the system, it can be expected that HV coins will hardly be exchanged for LV coins using the exchange function provided by the system. This is because users who have HV coins would be better off if they exchanged HV coins for fiat currency and bought LV coins through exchanges or inter-user transactions without going through the system. In that case, the circulation of HV coins will not decrease much, so after a while the exchange of LV coins to HV coins by the system may also stop. In order to increase the value of LV coins in such a case, it is sufficient to collect the LV coins in circulation. It is possible to forcibly collect LV coins from users who own LV coins in the same way as taxes, but it is unlikely that users will like to use crypto assets with such a mechanism.

In the blockchain system of the present invention, a part of the coins that the user pays to the system as a usage fee when the user uses the functions provided by the system to the user can be extinguished from the system without the system paying other users. to collect LV coins in circulation. Usage fees collected by the system that can be used to collect LV coins include transaction fees, smart contract execution fees (so-called gas fees), Proof-of-Search (Patent Document 3, Non-Patent Document 11) Task execution fee and the like.

These usage fees may be paid only with LV coins, and in this way, it is necessary to obtain LV coins even when the user performs transactions only with HV coins, so as long as transactions are performed on the system There is always a demand for LV coins. In this way, when the value of LV coins is lower than the exchange rate of the system, new LV coins are rarely issued, and part of the usage fee paid when the user uses the system functions It can be expected that the circulation of LV coins will decrease as they disappear from the system, and that the value of LV coins will recover over time.

With the above mechanism, the value of the LV coin is backed by the value of the HV coin, and as long as the HV coin has value, the LV coin has a value close to a certain amount of legal currency. Even if the value of LV coins declines for some reason, users do not need to rush to let go of LV coins and just wait for the value to recover naturally. Since HV coin does not have a mechanism to suppress price fluctuations, it can be expected that price fluctuations similar to Bitcoin will occur. The value of HV coin is not affected so much by the value of LV coin, and it can be expected that resistance to value declines is equivalent to that of Bitcoin. In addition, as the circulation of LV coins increases, the total number of HV coins in circulation will fall below the total number of mined coins, and as a result, the value of HV coins can be expected to rise. LV coins are suitable for using crypto assets for payment purposes, and HV coins are suitable for trading crypto assets for speculative purposes.

In addition to the issue of restoring the value of LV coins, there is the issue of how to determine the rate at which the system will convert from HV coins to LV coins. Terra gives authority to a specific node in the network, and this node introduces the transaction price in US dollars used throughout the blockchain system into the blockchain system, making this the exchange rate. A specific node that is authorized to introduce information outside the blockchain system into the blockchain system is commonly called an oracle. Such a method has the drawback of requiring trust in the oracle and the oracle being a single point of failure. If Oracle is attacked and an incorrect exchange rate is set, there is a risk that the mechanism that maintains the value of LV coins will collapse. It is not so easy to introduce a coin's trading price into a blockchain system without any assumption that a particular node is working correctly.

In addition to the above, there is the problem of violating seigniorage. Seigniorage is the profit from issuance of currency for the state, and by the state manufacturing and issuing coins, the difference between the cost of manufacturing coins and the face value of the coins can be used as financial income. Issuing a crypto asset that maintains a price of $1 can be viewed as violating the seigniorage that the US was supposed to have. In other words, when stablecoins are used for payments, savings, loans, etc., equivalent to legal currency, the amount of stablecoin issued will directly affect the inflation rate of the country that issues the corresponding legal currency. can be considered. In order not to disrupt the existing monetary system, it is desirable that crypto-assets do not violate the seigniorage of specific countries.
In the present invention, it is assumed that the expected value of the amount of calculation required to mine the HV coin is proportional to the value of the HV coin, and this is used as the exchange rate by the system. The expected value of the amount of computation required to mine a coin is an internal variable that is automatically calculated to adjust the expected value of the time it takes for a block to be added to the blockchain in Bitcoin. Implemented. This is a completely distributed mechanism that has a proven track record of operating with high reliability and is not easily attacked. Determining the value of LV at this rate does not peg it to any fiat currency, so changes in the value of LV or HV do not directly affect the value of any country's fiat currency. There is no fear of violating seigniorage.

The reason why the expected value of the amount of calculation required to mine HV coin is proportional to the value of HV coin is as follows. If the value of coins obtained from mining is greater than the monetary cost of mining, more miners will participate in mining, and conversely, if the amount of coins obtained from mining is less than the monetary cost of mining. , It is expected that the number of miners participating in mining will decrease. Also, since miners try to mine at the lowest possible cost, it can be expected that they will use the most efficient equipment at the time of mining. As a result, all miners can be expected to use similar equipment to mine, so the cost required for mining is largely determined by the electricity bill each miner pays. Assuming that electricity prices do not vary significantly among miners, we can expect that the ratio of computational complexity to the required price will remain roughly constant among miners in the short term.

All of the above examples are examples of how to make it possible to trade two types of coins, HV coin and LV coin, on a single blockchain system, but mining using multiple different consensus algorithms respectively By making it possible to trade multiple types of coins that can be used and multiple types of coins linked to different indicators, it is possible to trade three or more types of coins on a single blockchain system. good.

A block chain system according to a first invention is a block chain system operated by nodes participating in a peer-to-peer network, and users can perform transactions on the system using any type of coin among two or more types of coins. and set a limit value for the total amount of any type of coin, limited to cases where the total amount of coins of that type possessed by all users does not exceed the limit value A system is provided with a means for enabling a user to perform a transaction of exchanging a coin of this type for another type of coin using the function of the system, a means for enabling a user to mine the coin of the type, and a coin of the type is provided. It is characterized in that the larger the total amount mined so far, the larger the limit value.

A block chain system according to a second invention is the block chain system according to the first invention, wherein the user can exchange a coin possessed by the user for another type of coin by the function of the system. and means for calculating an exchange rate at this time. It is characterized by a rate such that it can be exchanged for a large number of coins of the other kind.

A blockchain system according to a third invention is the blockchain system according to the second invention, wherein the system receives coins from the user as a usage fee when the user uses the function provided by the system. It is characterized by having a means of disappearing from the system without paying other users.

A fourth invention is a non-transitory computer-readable medium containing a computer program for realizing the blockchain system according to any one of the first to third inventions.

By the present invention, a blockchain system that realizes both a mechanism for suppressing price fluctuations of coins against legal currency and a mechanism for preventing a plunge in the value of coins, and a computer program for realizing the blockchain system A temporary computer-readable medium is provided.

FIG. 4 is an image diagram of coin flow in an example of trading two types of crypto assets according to the present invention. FIG. 4 is a diagram showing an example of block structure in Examples 1 to 3; 1 is an image diagram of a blockchain system in an embodiment; FIG.

Next, an embodiment of the present invention will be described, but it goes without saying that various changes and modifications are possible without departing from the technical scope of the present invention.

Examples 1 to 3 of the first to third inventions are shown below. HV coins and LV coins can be transferred between users on these blockchain systems, and transactions on the system that exchange between these two types of coins are possible. Miners can only mine HV coins, and every time a block is added, a fixed number of new HV coins will be awarded to the miner who added the block. To conduct a transaction, the user electronically signs an item containing transaction data and the number of LV coins to be paid as a transaction fee, and broadcasts it to the network. When an item is registered on the blockchain, a transaction fee is deducted from the account of the user who broadcast the item.

Algorithms 1, 2 and 3 are commonly used in Examples 1, 2 and 3. The parts calling algorithms U and V in Algorithm 2 call the corresponding algorithms described later, depending on the embodiment. An example of the structure of the blocks in these embodiments is shown in FIG. Each system of Examples 1, 2, and 3 is an enhanced blockchain system that uses PoW, and uses the same technology as PoW. These blockchain systems are organized as peer-to-peer networks. Each miner is connected to several randomly selected miners, and the network of miners is loosely connected without a fixed topology (Fig. 3). Messages are broadcast by the gossip protocol. For a new node to join the network, it must know at least one miner that has already joined the network. Each miner keeps a copy of all information on the blockchain and knows the exact current time. User ID is the user's public key.

Each miner runs two threads in parallel, each running Algorithm 1 and Algorithm 2. The two threads share a list L of newly received items. This item is received by Algorithm 1, which is run by each miner, and only items recognized as valid transactions by Algorithm U are recorded on the blockchain. The states handled in the algorithm include the number of HV coins and LV coins owned by each user and the total number of HV coins mined so far. The initial state is all 0s.

Algorithm 1: Receive Item
begin
// Keep adding newly received items to the end of the item list.
while true do
Receive item t.
Add item t to item list L.
end while
end

Algorithm 2: Mining
begin
// First, decide the blockchain to be mined.
if this node is the first miner in the blockchain system then
Assign the initial state to s.
After that, we will process the initial block chain.
else
// Wait until other nodes add blocks.
repeat
Wait until new blocks are added by other nodes.
Call algorithm 3 with the added block as an argument and assign the result to state s.
until state s is not NULL.
After that, the chain to which the new block is added is processed.
end if

// Main loop
while true do
// Construct the next block b to add from the items in list L.
Initializes block b and internally registers b as the latest block in the chain being processed.
Sets the ID of the user running this node as the ID of the user who added b.
Compute the expected amount of computation Z required to add the next block from the time the block was added to the chain being processed.

For each item t in list L, do
Call algorithm U with (t, s, b) as arguments and assign the return value to state j.
if j is not null then
Add item t to block b.
Assign state j to s.
if the number of items that block b can contain has reached the system-imposed limit then
break.
end if
end if
end for
Remove the items contained in block b from list L.
Remove items older than a certain amount from list L.
Calls algorithm V with (b, s) as arguments and assigns the result to state s.
// At this point, the state after adding block b is assigned to s.

repeat
repeat
Set the current time as the added time of block b.
Compute the hash value of block b with a different nonce.
until a block is received or until a nonce that starts with log2 Z zero bits is found.
if log2 finds a nonce that starts with Z zero bits then
Add the found nonce to block b and broadcast it to the network.
After that, process the added chain of block b.
end if
if block r has been received, and the chain corresponding to block r is longer than the chain currently being processed, and the difference between the time when block r was added and the current time is less than or equal to a system-defined constant then
Calls algorithm 3 with block r as argument and assigns the result to t.
if t is not NULL then
Assign state t to s.
Move items not in the chain corresponding to block r to list L.
After that, process the chain corresponding to the newly added block r.
end if
end if
until until the chain being processed is updated.
end while
end

Algorithm 3: Validate the chain and return the state after adding all blocks if successful, NULL otherwise Input: block b
Output: verify the chain containing block b as the latest block, returning the latest state on success or NULL on failure
begin
If you don't have a chain with block b as the latest block, download it.
Initialize state s to the state at the start of the blockchain.
for all blocks k in the chain containing block b as the latest block do in chronological order
for every item t in block k do
Call algorithm U with (t, s, b) as arguments and assign the return value to state s.
if s is NULL then
return NULL.
end if
end for
Calls algorithm V with arguments (k, s) and assigns the result to state s.
end for
return s.
end

The blockchain system of Embodiment 1 is an embodiment of the first invention, and has algorithms 1, 2, 3, 1-U, and 1-V in addition to the blockchain system configuration using PoW. In this embodiment, algorithms 1-U and 1-V are called at locations where algorithms U and V are called in algorithms 1, 2, and 3, respectively.
In Embodiment 1, when an attempt is made to exchange LV coins for HV coins such that the total amount of HV coins possessed by all users exceeds the total amount of mined HV coins, such an exchange is performed. By failing the verification of the indicated item in Algorithm 1-U, the item is prevented from being registered on the blockchain. It also receives the market price of HV coin from Oracle.

Algorithm 1-U: Item verification and state update Input: item t, state s, latest block in chain b
Output: updated state if validation succeeds, NULL if validation fails
begin
Let user u be the sender of item t.
if verification of electronic signature of item t failed, or LV coins possessed by user u specified in state s are less than transaction fee of item t then
return NULL.
end if
Subtract the transaction fee of item t from the LV coins possessed by the specified user u in state s.

// Substitute X with the exchange rate from HV coin to LV coin. X HV coins and 1 LV coin are exchanged in the market.
Receive from the oracle the market price of HV coin at the time when the block before the block containing item t was added, and substitute it for X.

// Substitute Y with the exchange rate from LV coin to HV coin. Exchange Y HV coins and 1 LV coin.
Calculate the total amount of HV coins and LV coins owned by all users from state s, and substitute them for H and L.
Substitute the total amount of HV coins mined so far included in state s into M.
Let F be a function that calculates the upper limit of the HV coin circulation determined by the system.
Assign MIN((F(M)-H)/L, X) to Y.

if item t is a transaction that exchanges LV coins for HV coins then
if user u has less LV coins than the specified amount, or Y < 0 then
// If the circulation of HV coins exceeds the upper limit after exchange, Y < 0.
return NULL.
end if
Subtract the exchange amount from the LV coins possessed by user u in state s.
The amount exchanged at the rate of Y HV coins per LV coin is added to the HV coins possessed by user u in state s.
end if

if item t is a transaction that exchanges HV coins for LV coins then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the exchange amount from the HV coins possessed by user u in state s.
Add 1/X LV coins per HV coin to the LV coins possessed by user u in state s.
end if

if item t is a transfer of LV coins to specified account v then
if user u has less LV coins than the specified amount then
return NULL.
end if
Subtract the remittance amount from the LV coins possessed by user u in state s.
Add the remittance amount to the LV coins possessed by user v in state s.
end if

if item t is a transfer of HV coin to specified account v then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the remittance amount from the HV coins possessed by user u in state s.
Add the remittance amount to the HV coin possessed by user v in state s.
end if
return state s.
end

Algorithm 1-V: Input that updates the state due to the addition of a block: block b, state s
Output: state after update
begin
Assign u the ID of the user who added block b.
Add a constant defined by the system to "the number of HV coins possessed by user u" in state s.
Add the same constant as above to the “total amount of HV coins mined so far” in state s.
for every item t in the for block b do
Add the transaction fee of item t to "the number of LV coins possessed by user u" in state s.
end for
return state s.
end

The blockchain system of Embodiment 2 is an embodiment of the second invention, and has algorithms 1, 2, 3, 2-U, and 2-V in addition to the blockchain system configuration using PoW. In this embodiment, algorithms 2-U and 2-V are called at locations where algorithms U and V are called in algorithms 1, 2 and 3, respectively.
In Example 2, the exchange rate between the HV coin and the LV coin is calculated from the expected value of the amount of calculation required to add blocks in Algorithm 2-U.

Algorithm 2-U: Item verification and state update Input: item t, state s, latest block in chain b
Output: updated state if validation succeeds, NULL if validation fails
begin
Let user u be the sender of item t.
if verification of electronic signature of item t failed, or LV coins possessed by user u specified in state s are less than transaction fee of item t then
return NULL.
end if
Subtract the transaction fee of item t from the LV coins possessed by the specified user u in state s.

// Calculate the exchange rate from HV coin to LV coin from the expected value of the amount of computation required to add blocks and substitute it for X. Assume that X HV coins and 1 LV coin are exchanged in the market.
Calculate the expected value Z of the amount of computation required to add the next block from the time the block in the chain containing block b as the latest block was added, and multiply Z by a system-defined constant to X substitute.

// Substitute Y with the exchange rate from LV coin to HV coin. Exchange Y HV coins and 1 LV coin.
Calculate the total amount of HV coins and LV coins owned by all users from state s, and substitute them for H and L.
Substitute the total amount of HV coins mined so far included in state s into M.
Let F be a function that calculates the upper limit of the HV coin circulation determined by the system.
Assign MIN((F(M)-H)/L, X) to Y.

if item t is a transaction that exchanges LV coins for HV coins then
if user u has less LV coins than the specified amount, or Y < 0 then
// If the circulation of HV coins exceeds the upper limit after exchange, Y < 0.
return NULL.
end if
Subtract the exchange amount from the LV coins possessed by user u in state s.
The amount exchanged at the rate of Y HV coins per LV coin is added to the HV coins possessed by user u in state s.
end if

if item t is a transaction that exchanges HV coins for LV coins then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the exchange amount from the HV coins possessed by user u in state s.
Add 1/X LV coins per HV coin to the LV coins possessed by user u in state s.
end if

if item t is a transfer of LV coins to specified account v then
if user u has less LV coins than the specified amount then
return NULL.
end if
Subtract the remittance amount from the LV coins possessed by user u in state s.
Add the remittance amount to the LV coins possessed by user v in state s.
end if

if item t is a transfer of HV coin to specified account v then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the remittance amount from the HV coins possessed by user u in state s.
Add the remittance amount to the HV coin possessed by user v in state s.
end if
return state s.
end

Algorithm 2-V: Input that updates the state due to the addition of a block: block b, state s
Output: state after update
begin
Let u be the ID of the user who added block b.
Add a constant defined by the system to "the number of HV coins possessed by user u" in state s.
Add the same constant as above to the “total amount of HV coins mined so far” in state s.
for every item t in the for block b do
Add the transaction fee of item t to "the number of LV coins possessed by user u" in state s.
end for
return state s.
end

The blockchain system of Embodiment 3 is an embodiment of the third invention, and has algorithms 1, 2, 3, 3-U, and 3-V in addition to the blockchain system configuration using PoW. In this embodiment, algorithms 3-U and 3-V are called at locations where algorithms U and V are called among algorithms 1, 2 and 3, respectively.
In Example 3, half of the LV coins collected as transaction fees in Algorithm 3-V are eliminated from the system.

Algorithm 3-U : Item verification and state update Input: item t, state s, latest block in chain b
Output: updated state if validation succeeds, NULL if validation fails
begin
Let user u be the sender of item t.
if verification of electronic signature of item t failed, or LV coins possessed by user u specified in state s are less than transaction fee of item t then
return NULL.
end if
Subtract the transaction fee of item t from the LV coins possessed by the specified user u in state s.

// Calculate the exchange rate from HV coin to LV coin from the expected value of the amount of computation required to add blocks and substitute it for X. Assume that X HV coins and 1 LV coin are exchanged in the market.
Calculate the expected value Z of the amount of computation required to add the next block from the time the block in the chain containing block b as the latest block was added, and multiply Z by a system-defined constant to X substitute.

// Substitute Y with the exchange rate from LV coin to HV coin. Exchange Y HV coins and 1 LV coin.
Calculate the total amount of HV coins and LV coins owned by all users from state s, and substitute them for H and L.
Substitute the total amount of HV coins mined so far included in state s into M.
Let F be a function that calculates the upper limit of the HV coin circulation determined by the system.
Assign MIN((F(M)-H)/L, X) to Y.

if item t is a transaction that exchanges LV coins for HV coins then
if user u has less LV coins than the specified amount, or Y < 0 then
// If the circulation of HV coins exceeds the upper limit after exchange, Y < 0.
return NULL.
end if
Subtract the exchange amount from the LV coins possessed by user u in state s.
The amount exchanged at the rate of Y HV coins per LV coin is added to the HV coins possessed by user u in state s.
end if

if item t is a transaction that exchanges HV coins for LV coins then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the exchange amount from the HV coins possessed by user u in state s.
Add 1/X LV coins per HV coin to the LV coins possessed by user u in state s.
end if

if item t is a transfer of LV coins to specified account v then
if user u has less LV coins than the specified amount then
return NULL.
end if
Subtract the remittance amount from the LV coins possessed by user u in state s.
Add the remittance amount to the LV coins possessed by user v in state s.
end if

if item t is a transfer of HV coin to specified account v then
if the amount of HV coins owned by user u is less than the specified amount then
return NULL.
end if
Subtract the remittance amount from the HV coins possessed by user u in state s.
Add the remittance amount to the HV coin possessed by user v in state s.
end if
return state s.
end

Algorithm 3-V : Input that updates the state due to the addition of a block: block b, state s
Output: state after update
begin
Let u be the ID of the user who added block b.
Add a constant defined by the system to "the number of HV coins possessed by user u" in state s.
Add the same constant as above to the “total amount of HV coins mined so far” in state s.
for every item t in the for block b do
Add half of the transaction fee of item t to "the number of LV coins possessed by user u" in state s.
// Half of the transaction fee deducted in Algorithm 3-U disappears from the system without being paid to user u.
end for
return state s.
end

Claims (4)

A blockchain system operated by nodes participating in a peer-to-peer network, provided with means to allow users to conduct transactions on the system using any of two or more types of coins, either Equipped with a means to set a limit value for the total amount of coins of the type, and only when the total amount of coins of the type possessed by all users does not exceed the limit value It comprises means for enabling users to perform transactions to be exchanged by the function of the system, and means for enabling users to mine coins of that kind, and the larger the total amount of coins of that kind that have been mined so far, the greater the amount. A blockchain system characterized by a large limit value. 2. The block chain system according to claim 1, comprising means for allowing the user to perform a transaction for exchanging coins owned by the user for other types of coins by the function of the system, and at this time, the exchange rate is The exchange rate is calculated by converting one coin of a certain type possessed by the user to a larger number of coins of another type as the expected value of the amount of calculation required for mining the coin of that type is larger. A blockchain system characterized by a rate that can be exchanged for coins. The blockchain system according to claim 2, wherein coins received by the system from the user as usage fees when the user uses the functions provided by the system are extinguished from the system without the system paying other users. A blockchain system characterized by comprising means. A non-transitory computer-readable medium containing a computer program for implementing the blockchain system according to any one of claims 1 to 3.

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