JP6959649B2 - Cryptocurrency trading device, trading server device, cryptocurrency trading system, cryptocurrency trading method and program - Google Patents

Description

The present invention relates to a virtual currency trading device for trading virtual currencies between users, and more particularly to a virtual currency trading device for exchanging different virtual currencies.

In recent years, a technology called a blockchain that realizes distributed ledger management on a P2P network has been known.
A virtual currency (cryptocurrency) (Patent Document 1) that utilizes this blockchain as a transaction ledger is known, and has been used as a new settlement method or remittance method instead of cash.
Initially, only Bitcoin (registered trademark) was known as such a virtual currency, but nowadays, various virtual currencies (called altcoin) using the same mechanism are used. .. For example, Monacoin (registered trademark), Litecoin (Litecoin) and the like are known as altcoin.
Conventionally, when a virtual currency user wants to exchange his / her own virtual currency for another virtual currency, he / she uses an exchange or between users who hold different virtual currencies. There was no choice but to carry out mutual remittance transactions using the mechanism that Cryptocurrency has.

In the transaction of virtual currency using an exchange, the virtual currency is deposited on the exchange by trusting the exchange which is a third party.
Of course, there is a risk that the deposited virtual currency will be "taken away" to a malicious exchange, but even if it is a well-meaning exchange, there is a concern that they will be targeted and the deposited virtual currency will be leaked due to cracking or the like.

Further, in the method of "exchange" virtual currency between users holding different virtual currencies, for example, user A remits bitcoin to user B, and user B transfers the above MonaCoin to user A. The procedure of sending money is taken. In that case, the user B who receives the bitcoin may not send the monacoin to the user A as promised, and may "take away" the bitcoin.

As a technology for solving such security problems, the risk of bilateral transactions between users, which is called "Atomic Swap" (hereinafter referred to as "atomic swap"), has been eliminated without going through an exchange. A virtual currency transaction method has been proposed (Non-Patent Document 1).
This "atomic swap" allows secure transactions "trustless" (without trusting the exchange) without going through an exchange, as well as indirectly (indirectly) through special transactions. By exchanging currencies, it is possible to carry out secure transactions with "trustless (without trusting the user who is the partner of the bilateral transaction)". A "special transaction" is a transaction that specifies, in addition to the recipient, an expiration date and a hash value of a secret value randomly generated (determined) by one of the parties.
Participants in "atomic swaps" create the above special transactions with each other. Then, only when the recipient knows the above-mentioned randomly selected secret value, it is possible for the recipient to create a transaction to connect to a special transaction and receive the virtual currency.
Since the "secret value" needs to be disclosed in the process of transaction, it is not possible for only one of the participants to receive the virtual currency. Also, in general, a transaction is created so that the sender can recover the virtual currency after specifying the expiration date, so even if the atomic swap fails, either one will not lose the virtual currency.
Therefore, "atomic swap" can carry out indirect and secure transactions through special transactions.

JP-A-2017-207860

bitcoin wiki, [Searched March 1, 2018], Internet, <URL: https: // en. bitcoin. it / wiki / Atomic_cross-chain_trading>

As mentioned above, with "atomic swap", direct transactions are possible between users, and the risk of transactions via exchanges can be avoided.
However, when trying to buy or sell virtual currency using "atomic swap", there is no conventional interface that allows virtual currency users to exchange desired trading conditions, and find a trading partner with conditions. There was a problem that it was not easy.
The present invention has been made in view of the above problems, and provides a virtual currency trading device capable of matching virtual currency transaction conditions desired by a user and easily and safely starting a virtual currency transaction. The purpose is to do.

The present invention has been made to solve the above problems, and can be realized by the following forms.
The first embodiment according to the present invention is a virtual currency trading device for exchanging a first virtual currency and a second virtual currency, and the quantity desired by the user of the virtual currency trading device is described above. A sell order for the first virtual currency, which includes an input means for inputting an order content specifying a quantity of the second virtual currency to be exchanged for the first virtual currency, and the order content input by the input means. The transaction comprises a sell order sending means for sending a sell order to the network and a board information display means for displaying board information including the sell order sent to the network, and the transaction is the first virtual currency from one user. The first remittance information including the specific information indicating the remittance, the first receipt information indicating the receipt of the second virtual currency sent to the one user, and the said from another user. The second remittance information including the specific information indicating the remittance of the second virtual currency and the second receipt information indicating the receipt of the first virtual currency remitted to the other user are The board information display means is based on the number of the first received information with respect to the number of the first remittance information related to a specific user, which is made public to the network. It is characterized by a virtual currency trading device that displays the board information that gives the possibility of success of the transaction related to the user.
The second aspect according to the present invention is a transaction server device that mediates the transaction of virtual currency between a plurality of virtual currency trading devices, and each virtual currency trading device is a sell order and a sell order in which the exchange quantity of the virtual currency is specified. A buy order is sent to the network, and the transaction is the first remittance information including specific information indicating the remittance of the first virtual currency from one user, and the first remittance sent to the one user. To the other user, the first receipt information indicating the receipt of the second virtual currency, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the other user. The second receipt information indicating the receipt of the first virtual currency sent by the user and the second receipt information indicating the receipt of the first virtual currency sent to the network are made public on the network, and the board information for generating the board information according to the sell order sent to the network is generated. According to the generation means, the board information distribution means for distributing the board information to the virtual currency trading device, and the quantity of the second virtual currency related to the second remittance information, the above-mentioned one during execution of the transaction. According to the lending means for lending the second virtual currency to the user and the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. The transaction server is provided with an evaluation means for evaluating the possibility of success of the transaction related to the user, and the lending means determines the quantity of virtual currency to be loaned according to the evaluation result by the evaluation means. It features a device.
A third mode according to the present invention is a transaction server device that mediates a transaction of virtual currency between a plurality of virtual currency trading devices, and each virtual currency trading device is a second virtual currency with respect to the first virtual currency. A sell order with a specified exchange quantity is sent to the network, a buy order corresponding to the sell order is sent to the network, and the transaction is specific information indicating the transfer of the first virtual currency from one user. The first remittance information including the above, the first receipt information indicating the receipt of the second virtual currency sent to the one user, and the second virtual currency from another user. The second remittance information including the specific information indicating the remittance and the second receipt information indicating the receipt of the first virtual currency sent to the other user are disclosed to the network. A board information generation means for generating board information according to a sell order sent to the network, a board information distribution means for distributing the board information to the virtual currency trading device, and a board information distribution means which is open to the network. The present invention comprises an evaluation means for evaluating the possibility of success of the transaction relating to the user according to the number of the first received information relative to the number of the first remittance information relating to the specific user. The board information generating means is characterized by a transaction server device that assigns a user's evaluation result related to the sell order to the board information according to the evaluation result by the evaluation means.
A fourth aspect according to the present invention is a virtual currency trading system including a plurality of virtual currency trading devices for exchanging a first virtual currency and a second virtual currency, and a trading server device. In the transaction, the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the second virtual currency remitted to the one user The first receipt information indicating receipt, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the remittance sent to the other user. The second receipt information indicating the receipt of the first virtual currency is disclosed on the network, and the virtual currency trading device is the first in the quantity desired by the user of the virtual currency trading device. A network of input means for inputting an order content specifying the quantity of the second virtual currency to be exchanged for the virtual currency of the first virtual currency, and a sell order of the first virtual currency including the order content input by the input means. The transaction server device includes a sell order sending means to be sent to the network and a board information display means for displaying board information including the sell order sent to the network, and the transaction server device is a board corresponding to the sell order sent to the network. The board information generating means for generating information and the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. The evaluation means for evaluating the possibility of success of the transaction and the evaluation result of the user related to the sell order are added to the board information according to the evaluation result by the evaluation means, and the board information is used for the virtual currency transaction. The board information display means of the virtual currency trading device includes a board information distribution means to be distributed to the device, and the board information display means of the virtual currency trading device is characterized by a virtual currency trading system that displays the board information delivered by the board information distribution means. ..

With the above configuration, according to the present invention, it is possible to realize a virtual currency transaction device capable of matching the transaction conditions of the virtual currency desired by the user and easily and safely starting the transaction of the virtual currency. Can be done.

It is a schematic diagram which shows the structure of the system to which the virtual currency transaction apparatus of this embodiment is applied. It is a figure to outline the transaction of virtual currency. It is a figure which outlines the basic mechanism of atomic swap. It is a figure explaining the flow of atomic swap in detail. , It is a figure which shows the functional structure of the virtual currency transaction apparatus (terminal apparatus) which concerns on this embodiment. It is a figure explaining an example of the buy / sell order screen in the terminal apparatus of this embodiment. In this embodiment, it is a figure explaining the sell order placed by the user of the virtual currency. It is a figure which shows the functional structure of the transaction server which concerns on this embodiment. It is a flowchart explaining the sell order processing executed by the terminal device on the selling side. It is a flowchart explaining the board information generation processing executed by a transaction server. It is a flowchart explaining the buy order processing executed by the terminal device on the buying side. It is a flowchart explaining the atomic swap execution process executed by the terminal device on the selling side. It is a flowchart explaining the atomic swap execution process executed by the terminal apparatus on the buying side. It is a flowchart explaining the transaction evaluation process executed by a transaction server. It is a flowchart explaining the process after the transaction matching is established executed by the transaction server. It is a figure which shows the board information which reflected the transaction success probability of the user who made a sell order.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a system to which the virtual currency trading device of the present embodiment is applied.
FIG. 1A is a schematic diagram showing a configuration of a network including a terminal device as a virtual currency trading device of the present embodiment.
In the system 1 according to the present embodiment, virtual currency transaction devices (hereinafter, terminal devices) 10a, 10b, 10c, etc. related to the use of a plurality of users are connected to each other via the Internet.
Furthermore, on the Internet, a large number of minor devices 30 used by miners who participate in blockchain networks and perform mining work, and users of terminal devices 10a, 10b, 10c, etc. A transaction server 40, which provides board information necessary for conducting transactions such as exchanges, is connected to the transaction server 40.

The blockchain network x is composed of a large number of minor devices 30x (30x-1, 30x-2 ...) And client devices, and a large number of minor devices 30y (30y-1, 30y-2 ...) And client devices constitute the blockchain network x. The blockchain network y is configured.
These blockchain networks are P2P (Peer to Peer) networks, the blockchain network x is a network of virtual currency X, and the blockchain network y is a network of virtual currency Y.

There are many blockchains, including those used for cryptocurrencies. In addition to typical Bitcoin, altcoin is also known as a virtual currency. Ethereum, Monacoin, etc. are known as typical altcoins.

On the Internet, there are blockchain networks for operating and functioning Bitcoin, and blockchain networks for operating and functioning various altcoins.
Many minor devices 30 are connected to each blockchain network to perform proof-of-work work. In addition, some blockchain networks (virtual currencies) do not perform proof of work work as mining.

In either case, the blockchain network is a P2P network that does not have a centralized server. The same blockchain is stored in the storage of each minor device belonging to the blockchain network, the server device, and the storage provided in the pool server. This is why blockchain is called a decentralized transaction ledger.

FIG. 1B is a diagram showing a blockchain included in a device belonging to a blockchain network.
The outline of the blockchain will be described with reference to FIG. 1 (b).
A blockchain is established by connecting transaction information and the like that are generated sequentially in block units.

That is, in blockchain technology, data (a set) whose contents are to be guaranteed, such as transaction records and contracts, is handled in units called blocks. A blockchain is a block in which these blocks are connected by a predetermined method, that is, connected in a chain shape. A hash function is used in the generation of the blockchain, and the hash function is a function for obtaining a fixed-length hash value for arbitrary data of arbitrary length.
The hash function has the characteristic of being one-way, and it is easy to obtain the hash value from arbitrary data, but conversely, it is said that it is practically impossible to restore the original data from the hash value. NS.

In order to connect a new block to the blockchain, the hash value of the previous block in the chain and the transaction data of the new block to be connected are combined into one data called Merkle root, which is called the Nonce value. When the hash value (for example, SHA-256 hash) is calculated for the data to which the numerical value (for example, 32 bit fixed length numerical value) is connected, the nonce value such that the upper few bits (for example, 10 bit) become 0 is obtained.

Since the SHA-256 hash value is an almost random 256-bit value, the probability that the top 10 bits will be 0 when a certain Nonce value is selected is 1/1024, but due to the unidirectionality of the hash function described above, Basically, there is no other way than verifying whether or not the upper bit of the above hash value is 0 in a round robin for all Nonce values. The work of performing this brute force verification, finding the Nonce value in which the high-order bit of the hash value is 0, reporting it, and approving the block is called mining or proof of work (PoW).
As a result, as shown in FIG. 1 (b), each block of the blockchain includes the data of the block, the hash value of the immediately preceding block, and the Nonce value.

In such a blockchain, since each block has the hash value of the immediately preceding block, it is possible to confirm the validity of all blocks by tracing in order from the leading (oldest starting point) block. You can.
If you try to tamper with a block in the middle, you need to recalculate the Nonce value of all blocks after that block, but it is impossible in terms of computational complexity because the above-mentioned brute force must be performed for all blocks. ..
By having such a feature, the reliability of the blockchain is guaranteed.

As shown in Fig. 1, there is a demand for exchanging virtual currencies in the presence of different blockchain networks and different virtual currencies, and as a safe mechanism for that, for example, what is called atomic swap is already known. There is.
Conventionally, when a virtual currency user wants to exchange (exchange) his / her own virtual currency for another virtual currency, he / she uses an exchange or holds a different virtual currency (crypto currency). There was no choice but to make mutual remittance transactions using the mechanism of each virtual currency.
In the method using an exchange, for example, when a user A who holds Bitcoin desires MonaCoin, he / she deposits Bitcoin at a certain exchange and receives payment of MonaCoin of the same value from the exchange. Alternatively, when the user B who owns MonaCoin desires Bitcoin, he / she deposits MonaCoin at a certain exchange and receives payment of Bitcoin of the same value from the exchange.

In the transaction of virtual currency using such an exchange, the virtual currency is deposited in the exchange by trusting the exchange which is a third party.
Of course, there is a risk that the deposited virtual currency will be "taken away" to a malicious exchange, but even if it is a well-meaning exchange, there is a concern that they will be targeted and the deposited virtual currency will be leaked due to cracking or the like.

It is also possible to dislike such risks and "exchange" virtual currencies between users who hold different virtual currencies.
This method has the advantage that the exchange rate can be determined between users, but in such bilateral transactions, for example, user A remits bitcoin to user B, and user B sends Monacoin. The procedure of sending money to user A is taken.
In that case, the user B who receives the bitcoin may not send the monacoin to the user A as promised, and may "take away" the bitcoin.

As described above, there are security risks that cannot be ignored in both the method using the exchange and the method of exchanging virtual currencies between users.
Atomic swap is a technology to solve security problems when exchanging different virtual currencies, and it is possible to perform secure transactions "trustless" (without trusting the exchange) without going through the exchange. Of course, by exchanging currencies indirectly (indirectly) through special transactions, secure transactions are carried out with "trustless (without trusting the users who are the counterparts of bilateral transactions)". It is a virtual currency transaction (exchange) method that is possible.

In this specification, "remittance of virtual currency to users" is just a convenient expression.
In virtual currencies such as Bitcoin, the "transfer" of virtual currency is a virtual currency (currency value) of a predetermined unit that is distributed and recorded on the network (in Bitcoin, it is called UTXO: Unsent Transition Output). , It is a process of locking by the address as the user's public key or public key hash.
"UTXO" means an output that is not yet connected to another transaction in a "transaction" described below, and includes a ScriptPubKey that describes the owner's public key.
The owner of the public key that locks UTXO is the owner of UTXO, and the UTXO is the balance of the virtual currency owned by the owner.

The virtual currency "transfer" is newly created by unlocking the UTXO locked by the public key of the previous owner or the public key hash by the electronic signature generated by the previous owner. This is a process of connecting to a transaction and re-locking the UTXO of the newly created transaction with the public key of the next owner or the public key hash.
Then, this "transaction" is publicized (broadcast) to the blockchain network, and the transaction is approved and incorporated into the blockchain to perform "remittance (transfer of ownership of UTXO)".

What is done when "transferring" virtual currency is to unlock the UTXO, connect it to a new transaction, and the new transaction is approved as part of a new block, and some value information is used as data. There is no exchange between the user's terminal devices. Data indicating monetary value is not exchanged between terminal devices.
Therefore, the information indicating (balance) of the virtual currency is not stored in the terminal device. In this respect, virtual currencies are essentially different from some electronic money, such as Felica®, which has balance information in the IC chip.
The "wallet" software installed on the terminal device searches the blockchain network for the UTXO associated with the user's public key or public key hash to obtain the "balance" of the user's virtual currency. Can be presented to.

FIG. 2 is a diagram for outline a transaction of virtual currency, (a) is a diagram conceptually showing the basic structure of a transaction, and (b) is a diagram when a new transaction is connected to a previous transaction. It is a figure which shows the state of.
A "transaction" is a symbol of the transfer (transfer) of currency value from a remittance source to a remittance destination. It has an output, which is a field to indicate.
In addition, the "output" includes the remittance amount and the ScriptPubKey.
ScriptPubKey is a scripting language that defines conditions for unlocking this output (transaction).
In general, ScriptPubKey describes a script that can be unlocked only by digital signature with a specific private key, so that the ownership of the virtual currency owns the corresponding private key. It belongs to the account (user) of the remittance destination.
The "input" includes a script for unlocking the UTXO called ScriptSigma in order to use the UTXO. The ScriptSig is mainly an electronic signature for unlocking the UTXO required by the ScriptPubKey.

As shown in FIG. 2B, a new transaction is connected to the output corresponding to the ScriptPubKey specified by Index0 in the previous transaction.
Since no new transaction is connected to the output corresponding to the ScriptPubKey specified in Index1, the output remains UTXO.

The new transaction is a ScriptSigma containing the electronic signature of the user who connected (or does) the new transaction obtained by the ScriptPubKey of the previous transaction, and the hash value of the entire previous transaction as the transaction ID for specifying the previous transaction of the connection destination ( Transaction hash) and Index for identifying the ScriptPubKey to connect to in the previous transaction are included in the input.
The output includes a ScriptPubKey containing a public key (public key hash) for locking the UTXO of a new transaction to the connected user.
The electronic signature attached to the input of the new transaction is generated by encrypting the hash values of the data excluding the ScriptSigma of the new transaction and the connected ScriptPubKey in the previous transaction using the private key.

FIG. 3 is a diagram outlining the basic mechanism of atomic swap.
As described above, atomic swap is a method for exchanging different virtual currencies related to different blockchain networks between users A and B.
User A "remittances" virtual currency X (for example, Bitcoin) to user B, and user B has a considerable amount of virtual currency Y at a predetermined exchange rate with user A. "Send money" (for example, MonaCoin) to user A.

In the example described here, the user A "remittances" the virtual currency X first, and the user B "remittances" the virtual currency Y later.
Before the atomic swap, the public key is exchanged between users together with the determination of the conversion rate. Other processing is on-chain processing (processing using a blockchain mechanism), but public key exchange is a procedure that can be executed by E-mail or other means.

In atomic swap, a value (hash value H of secret value R) generated by a method that cannot be back-calculated from a value randomly selected by user A (secret value R described later) is used.
First, the virtual currency X of the user A to be remitted is the UTXO of the virtual currency owned by the user A locked by the public key of the user A or the public key hash.
This UTXO is unlocked by the electronic signature of the current owner, User A.
Then, the terminal device on the user A side is given the above-mentioned randomly selected value (secret value R) and is given an electronic signature that can be generated by the private key possessed by the user B. A special transaction having the SignaturePubKey (output) as the unlock condition as the UTXO is created (connected to the unlocked UTXO), and "remittance" is performed.

In addition, by setting TimeLock in case the atomic swap fails for some reason, a certain period of time has passed and an electronic signature that can be generated by the private key of the user A is given. It is generally added as an unlock condition for the above-mentioned special transaction.
At the time of creating the special transaction, no transaction is connected to the UTXO and it is not owned by anyone. After a certain period of time has passed, the user A can unlock the UTXO lock with his / her own electronic signature and recover it.

On the user B side, the virtual currency Y of the user B to be remitted is the UTXO of the virtual currency owned by the user B locked by the public key of the user B or the public key hash.
This UTXO is unlocked by the electronic signature of the user B.
Then, the unlock condition is that the above value (secret value R) randomly selected by the user A is given, and an electronic signature that can be generated by the private key of the user A is given. A special transaction having the above-mentioned ScriptPubKey as UTXO is created (connected to the unlocked UTXO), and "remittance" is performed.

In addition, in case of atomic swap failure, by setting TimeLock, a certain period of time has passed and an electronic signature that can be generated by the private key of user B is given, which is also a special transaction. Added as an unlock condition.
At the time of creating the special transaction, no transaction is connected to the UTXO and it is not owned by anyone. After a certain period of time has passed, the user B can unlock the UTXO lock with his / her own electronic signature and recover it.

In addition, a special transaction created by user B for "transfer" has given a secret value R, which is a condition for unlocking UTXO, and an electronic signature that can be generated by the private key of user A. When a new transaction is created, the above special transaction is unlocked, and when the UTXO of the new transaction is locked with its own public key, user A receives the virtual currency sent by user B. (The ownership of UTXO is transferred from user B to user A).
On the other hand, a special transaction created by user A for "transfer" assigns a secret value R, which is a condition for unlocking UTXO, and an electronic signature that can be generated by the private key possessed by user B. When the new transaction is created, the above special transaction is unlocked, and the UTXO of the new transaction is locked with its own public key, so that the user B transfers the virtual currency sent by the user A. It can be received (the ownership of UTXO is transferred from user A to user B).

Atomic swap will be described in more detail.
In step (1), the terminal device 10 used by the user A creates a first transaction Tx1 that "transfers" the virtual currency X to the user B, and sends (broadcasts) it to the network.
In the ScriptPubKey in the output of the first transaction Tx1, the hash value H of the secret value R randomly selected by the user A and the public key (or the address as the public key hash) of the user B who is the remittance destination). And are described.

Specifically, the ScriptPubKey of the first transaction Tx1 has, as the unlock condition of this output (UTXO), (1) the hash value of the secret value R described in the ScriptPubKey and the transaction corresponding to the first transaction Tx1. Confirmation of matching with the hash value of the secret value R described in (2) Verification of the electronic signature and public key of the recipient (sending destination) is requested.
That is, when the secret value R randomly selected by user A and the electronic signature and public key of user B on the receiving side are specified in the input of the corresponding transaction, the output of the first transaction Tx1 ( UTXO) can be unlocked.
In addition, the ScriptPubKey of the first transaction Tx1 confirms the time stamp when (1) the public key of the remittance source and (2) the electronic signature of the remittance source are input after the expiration date (timeout) of the TimeLock. And ask for signature verification.

That is, the unlock condition of the output (UTXO) of the first transaction Tx1 is
(Before timeout) User B's digital signature and public key, user A's randomly selected secret value R
(After time-out) User A's digital signature and public key.
The terminal device 10b used by the receiving user B creates a transaction (fourth transaction Tx4 described later) in which the user B's own electronic signature, public key, and secret value R are described in the input. The receipt of the virtual currency X using the first transaction Tx1 can be completed.

As described above, TimeLock is set in the first transaction Tx1, and when the corresponding transaction (fourth transaction described later) is not created within a predetermined time after the creation of the first transaction Tx1 (TimeLock deadline ends). Then) the transaction times out. In this case, the electronic signature and public key of the user A who is the remittance source enables "Refund" to the user A.
Further, the ScriptSigma in the input of the first transaction Tx1 includes the electronic signature of the user A.
This digital signature is the first transaction to unlock the virtual currency X (UTXO) locked in the public key or public key hash of user A for "remittance" (to user B). It is given to Tx1.

The created first transaction Tx1 is open to the blockchain network x of the virtual currency X, and the value of the hash value H becomes known to the user B (terminal device 10b).
As described above, the output (UTXO) of the first transaction Tx1 can be unlocked by the electronic signature and public key of the user B and the secret value R randomly selected by the user A.
At this point, since the user B (terminal device 10b) does not know the secret value R, the output (UTXO) of the first transaction Tx1 is produced only by his / her own electronic signature (creating the fourth transaction Tx4). Cannot be unlocked (cannot receive user A's virtual currency X).
On the other hand, user A cannot collect the "remittance" virtual currency X (bitcoin) before the TimeLock deadline.

In step (2), the terminal device 10b used by the user B creates a second transaction Tx2 that "transfers" the virtual currency Y to the user A, and sends (broadcasts) the virtual currency Y to the blockchain network y. do.
In the ScriptPubKey in the output of the second transaction Tx2, the hash value H published on the blockchain network x of the virtual currency X and the public key of the user A who is the remittance destination are described.

Similar to the above, the ScriptPubKey of the second transaction Tx2 has, as the unlock condition of this output (UTXO), (1) the hash value of the secret value R described in the ScriptPubKey and the transaction corresponding to the second transaction Tx2. Confirmation of matching with the hash value of the secret value R described in (2) Verification of the electronic signature and public key of the recipient (sending destination) is requested.
The output (UTXO) of the second transaction Tx2 when the secret value R randomly selected by the user A and the digital signature and public key of the receiving user A are specified in the input of the corresponding transaction. Can be unlocked.
In addition, the ScriptPubKey of the second transaction Tx2 confirms the time stamp and verifies the signature when (1) the public key of the remittance source and (2) the signature of the remittance source are input after the timeout after the TimeLock deadline has passed. Ask for.

That is, the unlock condition of the output (UTXO) of the second transaction Tx2 is
(Before timeout) User A's digital signature and public key, user A's randomly selected secret value R
(After time-out) User B's digital signature and public key.
The terminal device 10 used by the receiving user A creates a transaction (third transaction Tx3 described later) in which the user A's own electronic signature, public key, and secret value R are described in the input. The receipt of the virtual currency Y using the second transaction Tx2 can be completed.

TimeLock is set in the second transaction Tx2, and if the corresponding transaction (third transaction Tx3 described later) is not created within a predetermined time after the creation of the second transaction Tx2 (when the TimeLock deadline expires), the transaction is performed. Times out. In this case, the electronic signature and public key of the user B, who is the remittance source, enables "Refund" to the user B.

Further, the ScriptSigma in the input of the second transaction Tx2 includes the electronic signature of the user B.
This digital signature is given to the second transaction Tx2 to unlock the virtual currency (UTXO) locked in the public key or public key hash of user B for remittance (to user A). Will be done.

The output (UXTO) of the second transaction Tx2 can be unlocked by the electronic signature of the user A, the public key, and the secret value R.
In addition, user B cannot collect the virtual currency Y (MonaCoin) that has been "transferred" before the TimeLock deadline.
The second transaction Tx2 is open to the blockchain network y of the virtual currency Y.

In step (3), the terminal device 10 used by the user A creates a third transaction Tx3 for receiving the virtual currency Y and sends it to the network.
The third transaction Tx3 corresponds to the second transaction Tx2, and in particular, the ScriptSigma (input) of the third transaction Tx3 corresponds to the ScriptPubKey (output) of the second transaction Tx2.

The public key (address as a public key hash) of the user A is described in the ScriptPubKey in the output of the third transaction Tx3.
Further, the ScriptSigma in the input of the third transaction Tx3 includes a secret value R randomly selected by the user A, the electronic signature of the user A, and the public key.
As described above, in the second transaction Tx2, the ScriptPubKey requires the secret value R and the electronic signature and public key of the user A as the output unlock condition, and the contents corresponding to these are described. ing.

User A (terminal device 10) creates the third transaction Tx3, unlocks the output (UTXO) of the second transaction Tx2, and uses the output (UTXO) of the third transaction Tx3 as the public key of the user A. Alternatively, by locking to the public key hash, the virtual currency Y "transferred" by the user B can be received.
Then, since the third transaction Tx3 is also disclosed (broadcast) to the blockchain network y of the virtual currency Y, the secret value R becomes known to the user B.

In step (4), the terminal device 10b used by the user B creates a fourth transaction Tx4 for receiving the virtual currency X and sends it to the network.
The fourth transaction Tx4 corresponds to the first transaction Tx1, and in particular, the ScriptSigma of the fourth transaction Tx4 corresponds to the ScriptPubKey of the first transaction Tx1.
The public key (address as a public key hash) of user B is described in the ScriptPubKey in the output of the fourth transaction Tx4.

Further, the ScriptSigma in the input of the fourth transaction Tx4 includes the secret value R disclosed to the blockchain network (as a result of the third transaction Tx3) and the electronic signature of the user B.
As described above, the ScirptPubKey of the first transaction Tx1 requests the electronic signature, public key, and secret value R of the user B as the unlock condition of the output (UTXO), and the contents corresponding to these are described. There is.
User B (terminal device 10b) creates the fourth transaction Tx4, unlocks the output (UTXO) of the first transaction Tx1, and uses the output (UTXO) of the fourth transaction Tx4 as the public key of the user B. Alternatively, by locking to the public key hash, the user A can receive the virtual currency X "transferred".

In FIG. 3, the first transaction Tx1 and the second transaction Tx2 indicating the "remittance" of the virtual currency can be considered as the first "remittance information" and the second "remittance information", respectively.
Further, the third transaction Tx3 and the fourth transaction Tx4 indicating the "receipt" of the virtual currency can be considered as the first "receipt information" and the second "receipt information".
It should be noted that the remittance destination (receipt) is used as the release (unlock) condition (contents required for input of the third transaction Tx3 and the fourth transaction Tx4 for receipt) required by the first transaction Tx1 and the second transaction Tx2 for remittance. In some cases, the public key of the side) is not required.
Further, in the output of the third transaction Tx3 and the fourth transaction Tx4 for receiving, the public key hash (address) of the receiving side may be specified, or the public key itself may be specified.

There are various conditions for describing transaction scripts, but in atomic swaps, the secret value R (and its hash value H) is important, and only those who know this value can connect subsequent transactions (UTXO). You can unlock and receive virtual currency).
In the following description, the public key of the receiving side is not specified in the input of the third transaction Tx3 and the fourth transaction Tx4, and the public key is specified in the output (P2PK: a method called Pay to Public Key). However, the present embodiment is not limited thereto.
In the present embodiment, the public key of the receiving side is described in the input of the third transaction Tx3 and the public key of the fourth transaction Tx4, and the public key hash (address) of the receiving side is specified in the output (P2PKH: Pay to Public Key Hash). This method is also called).
Regarding the first transaction Tx1 and the second transaction Tx2, the present embodiment includes both a case where the public key of the remittance destination is specified in the output and a case where the public key hash of the remittance destination is specified.

FIG. 4 is a diagram for explaining the flow of the conventional atomic swap in detail.
The period from the first transaction Tx1 to the fourth transaction Tx4 shown in FIG. 3 is the execution period of the atomic swap.
In step S1, the terminal device 10 of the user A who first "transfers" the virtual currency generates the electronic signature of the user A (Sigma1 for the first transaction Tx1). This process is performed using the hardware wallet, and the user A connects the hardware wallet HW_A to the terminal device 10. The private key of user A is stored in the hardware wallet. Further, the hardware wallet HW_A has a signature generation processing unit (circuit) for generating an electronic signature using the stored private key.

In step S2, the terminal device 10 creates the first transaction Tx1. This is a transaction for "transferring" the virtual currency X to the user B.
The first transaction Tx1 includes the electronic signature of the user A (SigA1 described above) as the input (ScriptSigma), the hash value H of the secret value R described above as the output (ScriptPubKey), and the user B who is the remittance destination. Includes the public key (PubKeyB) of.
Further, the input of the first transaction Tx1 includes the hash (transaction ID) of the previous transaction.
The terminal device 10 sends the first transaction Tx1 to the blockchain network x of the virtual currency X.
When the first transaction Tx1 is disclosed to the blockchain network x of the virtual currency X, the hash value H is also disclosed.
After this, preferably, the hardware wallet HW_A of the user A is removed from the terminal device 10.

In response to this, in step S3, the electronic signature of the user B (SigmaB1 for the second transaction Tx2) is generated in the terminal device 10b of the user B who later "transfers" the virtual currency. This process is also performed using the hardware wallet, and the user B connects the hardware wallet HW_B to the terminal device 10b. The private key of user B is stored in this hardware wallet HW_B. Similar to the above, the hardware wallet HW_B has a signature generation processing unit (circuit) for generating an electronic signature using the stored private key.

In step S4, the terminal device 10b creates a second transaction Tx2. This is a transaction for "transferring" the virtual currency Y to the user A.
The second transaction Tx2 includes the electronic signature of the user B (SigB2 described above) as the input (ScriptSig), and the hash value H and the remittance published on the blockchain network x of the virtual currency X as the output (ScriptPubKey). It contains the public key (PubKeyA) of the previous user A.
Further, the input of the second transaction Tx2 includes the hash (transaction ID) of the previous transaction.
The terminal device 10b sends the second transaction Tx2 to the blockchain network y of the virtual currency Y.
After this, preferably, the user B's hardware wallet HW_B is removed from the terminal device 10b.

Next, in step S5, the terminal device 10 of the user A generates the electronic signature of the user A (Sigma2 for the third transaction Tx3). This process is also performed using a hardware wallet.
In step S6, the terminal device 10 creates a third transaction Tx3. This is a transaction for unlocking the output (UTXO) of the second transaction Tx2 and "sending" (receiving) the virtual currency Y to the user A himself (the output of the third transaction Tx3 (the output of the third transaction Tx3). Unlock UTXO) and connect the transaction that locked UTXO with the public key (public key hash) of user A).

The third transaction Tx3 includes the electronic signature of the user A himself (the above Sigma2) and the above-mentioned secret value R as the input (ScriptSigma), and the public disclosure of the user A himself who is the remittance destination as the output (ScriptPubKey). Contains the key (PubKeyA).
Further, the input of the third transaction Tx3 includes a hash (transaction ID) of the second transaction Tx2 which is the previous transaction.
The terminal device 10a sends the third transaction Tx3 to the blockchain network y of the virtual currency Y.
When the third transaction Tx3 is published on the blockchain network y of the virtual currency Y, the secret value R is also published on the blockchain network y.
After this, preferably, the hardware wallet HW_A of the user A is removed from the terminal device 10.

In response to this, in step S7, the electronic signature of the user B (SigmaB2 for the fourth transaction Tx4) is generated in the terminal device 10b of the user B who later "transfers" the virtual currency. This process is also performed using the hardware wallet, and the user B connects the hardware wallet HW to the terminal device 10b.

In step S8, the terminal device 10b creates the fourth transaction Tx4. This is a transaction for unlocking the output (UTXO) of the first transaction Tx1 and "sending" (receiving) the virtual currency X to the user B himself (the output (UTXO) of the fourth transaction Tx4). ) Is unlocked, and the transaction that locked UTXO with the public key (public key hash) of user B is connected.
The fourth transaction Tx4 includes the electronic signature of the user B (SignB2 above) and the secret value R disclosed to the blockchain network y of the virtual currency Y as the input (ScriptSig), and as the output (ScriptPubKey). , The public key (PubKeyB) of the user B who is the remittance destination is included.
Further, the input of the fourth transaction Tx4 includes a hash (transaction ID) of the first transaction Tx1 which is the previous transaction.
The terminal device 10b sends the fourth transaction Tx4 to the blockchain network x of the virtual currency X.

The conventionally known atomic swap mechanism described above has a problem that it takes time to exchange virtual currencies.
Especially when Bitcoin transactions are processed on the blockchain, the processing of the first transaction Tx1 and the third transaction Tx3 is averaged until the processing of the first transaction Tx1 and the third transaction Tx3 is incorporated into the block of the blockchain due to the above-mentioned PoW by the minor devices constituting the network. It takes 60 minutes.

Currently, it is known that it takes about 10 minutes for one block of Bitcoin to be approved, and it is said that six blocks need to be connected until the blockchain is almost completely trusted.
Therefore, it takes about 10 minutes × 6 = 60 minutes for the first transaction Tx1 and the second transaction Tx2 to be completely incorporated into the block.

During that time, since the third transaction Tx3 and the fourth transaction Tx4 for receiving the virtual currency "transferred" by each other's users cannot be sent, the virtual currency to be received can be used for the next transaction. No.
Furthermore, the atomic swap mechanism has the advantage that virtual currencies can be exchanged directly between users without going through an exchange, but it is not easy to find a trading partner that meets the trading conditions. The transaction conditions are, for example, the type of virtual currency to be remitted, the type of virtual currency to be deposited, the exchange rate between the virtual passage to be remitted and the virtual passage to be deposited, and the like.
The virtual currency trading system of the present embodiment makes it easy to find a trading partner who meets the trading conditions in atomic swap, and aims to improve the convenience of trading.

5A and 5B are diagrams showing a functional configuration of a virtual currency transaction device (terminal device) according to the present embodiment, FIG. 5A is a diagram showing a functional configuration by hardware, and FIG. 5B is a block showing a functional configuration by software. It is a figure.
The terminal devices 10a, 10b, 10c ... Of the present embodiment are commonly used by a large number of users who use the virtual currency, and will be described as the terminal devices 10 having a common configuration.
In the following description, as an example, the processing performed between the user A, the terminal device 10a, and the terminal device 10b of the user B will be described.
Then, for example, the process performed by the terminal device 10a used by the user A and the process performed by the terminal device 10b used by the user B, which will be described in the present embodiment, can be interchanged with each other.

In the following description, in some cases, user A places a sell order using the terminal device 10a and user B places a buy order using the terminal device 10b, and vice versa, user B places a sell order. In some cases, the user A places a buy order.
That is, in the above description, the terminal device 10a is in a position to determine the secret value R and lead the atomic swap, but of course, when the terminal device 10b determines the secret value R and leads the atomic swap. Can also occur. In this case, the terminal device 10b performs the processing of the terminal device 10a described in the present embodiment, and conversely, the terminal device 10a performs the processing of the terminal device 10b.
The terminal device 10a and the terminal device 10b are essentially the same device and can execute the same process, and can execute different processes depending on the difference in roles.

As shown in FIG. 5A, the terminal device 10 executes a general-purpose operating system that controls the entire device. The terminal device 10 includes a CPU (Central Processing Unit) 11 and a RAM (Random Access Memory) 12. Further, the terminal device 10 includes a drive device 13, a recording medium 14, a ROM (Read Only Memory) (not shown), a network I / F15, and an external IO I / F16.
The CPU 11 executes a program that realizes the functions of the terminal device 10. In the RAM 12, various programs, temporary data, and variables are expanded for processing by the CPU 11.
The drive device 13 is a device that reads or writes information stored in the recording medium 14. The recording medium 14 stores the information written by the drive device 13. The recording medium 14 is at least one of a type of storage medium such as a hard disk, SSD (Solid State Drive), CD (Compact Disc), DVD (Digital Versaille Disc), and Blu-ray Disc. Further, for example, the terminal device 10 includes a drive device 13 corresponding to the type of the recording medium 14 in the terminal device 10.
Programs and data are stored in at least one of the recording medium 14 and the ROM. The network I / F15 connects the terminal device 10 to the network. The external IO I / F 16 connects peripheral devices to the terminal device 10.

A hardware wallet HW that stores a private key and is used for creating a digital signature can be connected to the external IO I / F16.
Further, the terminal device 10 includes an input device 17 such as a mouse and a keyboard and a display device 18 such as a liquid crystal display, and the user can buy and sell virtual currency on the buy and sell order screen displayed on the display device 18. Can be done.

Further, as shown in FIG. 5B, the CPU 11 executes atomic swap with the interface processing unit 21, the sell order processing unit 22, the buy order processing unit 23, the board information display processing unit 24, and the processing unit as processing units. The processing unit 25 and the processing unit 25 are executed.
The atomic swap execution processing unit 25 includes an R value determination processing unit 25a, a hash processing unit 25b, a transaction creation processing unit 25c, a digital signature generation processing unit 25d, a transaction transmission processing unit 25e, and a network search processing unit 25f. ,including.

The interface processing unit 21 is a processing unit for displaying the buy / sell order screen 100 on the display device 18 and accepting an input using the input device 17 for the buy / sell order screen 100.
The items set on the buy / sell order screen 100 are stored in the RAM 12.
The sell order processing unit 22 is a processing unit for placing a sell order of virtual currency based on an input to the buy / sell order screen 100.
The buy order processing unit 23 is a processing unit for placing a buy order of virtual currency based on a selection operation for a buy board (board information) displayed on the buy / sell order screen 100.
The board information display processing unit 24 is a process of displaying the board information received from the transaction server 40 or the board information generated from the sell order collected by searching the blockchain network by the terminal device 10 itself on the interface processing unit 21. It is a department.

FIG. 6 is a diagram illustrating an example of a buy / sell order screen in the terminal device of the present embodiment.
The buy / sell order screen 100 displays a sell order column 101 for placing a sell order of virtual currency and a board information displaying a list of sell orders placed from the sell order column 101 displayed on the own terminal or another terminal. It is provided with a buying board 102 for placing a buy order.
This is just an example, and a screen for placing a sell order and a screen for displaying a buy board may be prepared separately.
In the sell order column 101, for example, it is possible to set how much (how many units) the virtual currency X is to be sold and how many (how many units) the virtual currency Y is to be sold.
In this example, only the case where the reference virtual currency X is sold (exchanged) with the virtual currency Y is described, but it is not limited to this, and it is possible to place a sell order between other virtual currencies. May be good.

In the terminal device 10 of the user on the selling side, the quantity of the virtual currency X to be sold is input in the input field 101a, and the amount of the virtual currency Y to be exchanged (want to buy instead) is input in the input field 101b, and the order is placed. When the button 101c is selected, the sell order processing unit 22 processes the sell order. As will be described later, a sell order is performed by broadcasting a transaction in which the contents of the order are described in an area called OP_RETURN of the output of the contents of the order. OP_RETURN is an area where 80 bytes of free data can be written in the transaction output.

In OP_RETURN, even if the terminal device 10 (wallet) goes offline after placing a sell order, the URL or IP address of the notification destination can be returned to online when there is a buy order for the sell order. Can be described.
As will be described later, when there is a buy order based on the board information, the transaction server 40 notifies the notification destination described in OP_RETURN of the corresponding sell order to ensure the terminal device on the selling side. Control so that transactions can be started smoothly online.
The board information of the sell order acquired or generated by the board information display processing unit 24 is displayed on the buy board 102.
When an arbitrary sell order (which meets the conditions of the buyer's user) is selected from the sell orders displayed on the buy board 102 in the terminal device 10 of the buyer's user, the buy order processing unit 23 processes the buy order.
In the past, it was not easy to find a trading partner with trading conditions when trading with atomic swaps, but by using such board information, it is possible to easily find a trading partner with meeting conditions. ..

The sell order and the buy order are two sides of the same coin. For example, in the sell order shown on the buy board 102 of FIG. 6, there is a sell order by the user E, "I want to sell 100 units of virtual currency X with 70 units of virtual currency Y".
The buy order placed by selecting this sell order is an order to "buy" 100 units of virtual currency X in exchange for 70 units of virtual currency Y as desired by user E, and at the same time, 70 units of virtual currency. It is nothing but an order to "sell" the currency Y in exchange for 100 units of virtual currency X.

FIG. 7 is a diagram illustrating a sell order placed by a user of the virtual currency in the present embodiment.
As described above, the sell order is performed by broadcasting a transaction in which the contents of the order are described in an area called OP_RETURN of the output of the contents of the order.
The board information in the buying board 102 of FIG. 6 is a collection of sell orders placed by various users under desired conditions and displayed, and the terminal device 10 of each user performs the following processing. It is realized by.

That is, as shown in FIG. 7, the terminal device 10a of the user A broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X in 150 units of virtual currency Y.
The terminal device 10b of the user B broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X for 200 units of virtual currency Y.
The terminal device 10c of the user C broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X for 250 units of virtual currency Y.

The terminal device 10d of the user D broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X for 200 units of virtual currency Y.
The terminal device 10e of the user E broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X for 70 units of virtual currency Y.
The terminal device 10f of the user F broadcasts a transaction in OP_RETURN stating that he / she wants to sell 100 units of virtual currency X in 80 units of virtual currency Y.

In the buy board 102 of FIG. 6, as an example, the sell orders of each user shown in FIG. 7 are displayed in ascending order of the exchange rate for the virtual currency X, for example.
Further, when a single user places a plurality of sell orders, the display may be rearranged for each user.
Further, as will be described later, the sell orders may be rearranged and displayed according to the transaction success probability for each user who has placed a sell order.
In FIG. 6, for convenience, the sell order is displayed with the user attached, but in reality, the wallet address (public key, public key hash) of the user is displayed.
When a buy order is placed for the sell order of the buy plate 102 of FIG. 6 (when the sell order is selected), the user on the selling side who placed the selected sell order and the user on the buying side who selected the sell order are used. Atomic swap is performed by the atomic swap execution processing unit 25 between the person and the person.

Returning to FIG. 5B, each processing unit included in the atomic swap execution processing unit 25 will be described.
In the present embodiment, the R value determination processing unit 25a is a processing unit that determines the random value R in the terminal device 10a on the selling side.
The hash processing unit 25b is a processing unit that calculates a hash value H of a random value R determined by the R value determination processing unit 25a.

The transaction creation processing unit 25c is a processing unit for creating an atomic swap transaction based on the contents of the sell order or the selected buy order in the board information that triggered the atomic swap.
The electronic signature generation processing unit 25d is a processing unit for controlling the hardware wallet HW and generating an electronic signature by using the private key stored in the hardware wallet HW.
The hardware wallet HW connected to the terminal device 10 generates an electronic signature using a private key storage unit (not shown) that stores (stores) the private key and a private key stored in the private key storage unit, respectively. It is provided with a signature generator (circuit) (not shown).

The hardware wallet HW generates an electronic signature in the signature generation unit under the control of the electronic signature generation processing unit 25d.
Alternatively, the hardware wallet HW may have only a function of storing the private key, and the CPU 11 (electronic signature generation processing unit 25d) may create an electronic signature.
The hardware wallet connected to the terminal device 10 is a different hardware wallet that belongs to the user A and the user B, respectively, and stores the private key of each user.

The transaction transmission processing unit 25e is a processing unit for transmitting the created transaction to the blockchain network via the network I / F15.
The network search processing unit 25f is a processing unit that searches the blockchain network and acquires the values (secret value R, hash value H) required for atomic swap from the approved and published transaction.

8A and 8B are diagrams showing a functional configuration of a transaction server according to the present embodiment, FIG. 8A is a diagram showing a functional configuration by hardware, and FIG. 8B is a block diagram showing a functional configuration by software.
As shown in FIG. 8A, the transaction server 40 includes a CPU 41, a RAM 42, an HDD 43, a ROM (not shown), and a network I / F 44. The CPU 41 executes a general-purpose operating system that controls the entire device and realizes the functions of the transaction server 40. Various programs, temporary data, and variables are expanded in the RAM 42 for processing by the CPU 41 that executes the program. Programs and data are stored in the HDD 43 and the ROM. The network I / F44 connects the transaction server 40 to the network.

Further, as shown in FIG. 8B, the CPU 41 includes a sell order acquisition processing unit 51, a board information generation processing unit 52, a board information distribution processing unit 53, and a buy order notification processing unit 54 as processing units. , The transaction evaluation processing unit 55 and the credit / loan processing unit 56 are executed.
Further, the transaction server 40 includes an order information storage unit 61, a board information storage unit 62, and a transaction evaluation storage unit 63 as storage units.
The sell order acquisition processing unit 51 searches the blockchain network x of the virtual currency X, and when a sell order using OP_RETURN is found, the sell order acquisition processing unit 51 collects the contents and stores the contents in the order information storage unit 61. ..

The board information generation processing unit 52 performs a process of generating board information based on the order information stored in the order information storage unit 61 and storing it in the board information storage unit 62.
The board information distribution processing unit 53 performs a process of distributing the board information stored in the board information storage unit 62 to the terminal device 10 in response to a request from the terminal device 10.
The buy order notification processing unit 54 performs a process of notifying the terminal device on the selling side of a buy order for the sell order included in the board information.

The transaction evaluation processing unit 55 searches the blockchain networks x and y of the virtual currencies X and Y, and finds the number of the first transaction Tx1 and the third transaction Tx3 of the atomic swap performed by a specific user in the past. The number of successful transactions and the probability of successful transactions are evaluated from the numbers, and the evaluation results are stored in the transaction evaluation storage unit 63.
The credit / loan processing unit 56 monitors the atomic swap performed on the blockchain network, and during the execution, performs a process of lending a virtual currency in an amount (quantity) corresponding to the transaction amount to the user.
The term "lending" in the present embodiment only means remittance of virtual currency in an amount (quantity) corresponding to the transaction amount to the user. Regarding "refund" after the user acquires virtual currency due to normal termination or cancellation of atomic swap, the remittance transaction to the wallet of the transaction server 40 will be published (broadcast) separately on the user (terminal device) side. It is done by.
The transaction success probability and the number of transaction successes of the atomic swap for each user stored in the transaction evaluation storage unit 63 may be reflected in the board information generated by the board information generation processing unit 52.

That is, in the board information displayed on the buy / sell order screen 100 of the terminal device 10 shown in FIG. 6, the transaction success probability and the number of transaction successes of the user on the selling side are displayed in association with each sell order. By doing so, the user on the buying side can select a sell order with a high probability of successful transaction and place a buy order.
In the board information, the sell orders may be sorted and displayed according to the transaction success probability and the transaction success count.
The order information storage unit 61, the board information storage unit 62, and the transaction evaluation storage unit 63 may be set in any of the RAM 42 and the HDD 43.
That is, the order information acquired from the blockchain network, the generated board information, the transaction success probability evaluation of each user, etc. may be treated only as temporary data held in the RAM 42, or stored as a file in the HDD 43. After that, it may be loaded on the RAM.

In the description of FIG. 8, each processing unit performs a process of acquiring a specific transaction by searching the blockchain data on the network. Further, when the transaction server 40 stores the complete blockchain acquired from the network in the HDD 43, each processing unit acquires a specific transaction by searching the blockchain data stored in the HDD 43. You may.

FIG. 9 is a flowchart illustrating a sell order process executed by the terminal device on the selling side.
In step S101, the CPU 11 (interface processing unit 21) determines whether or not the sell order operation has been performed by using the sell order column 101 of the buy / sell order screen 100.
When it is determined that the sell order operation has been performed (Yes in step S101), the CPU 11 (sell order processing unit 22) executes a transaction in which the contents of the sell order set in the sell order column 101 are described in OP_RETURN in step S102. create.
It is preferable to include the wallet address (public key, public key hash) of the user on the selling side in the content of the sell order.
Then, in step S102, the CPU 11 (sell order processing unit 22) performs sell order processing by sending (broadcasting) the transaction created in step S101 to the blockchain network.
When the selling user sells the virtual currency X, the transaction is sent to, for example, the blockchain network x of the virtual currency X.
At this time, the CPU 11 may broadcast a transaction for remittance of a predetermined fee (for example, virtual currency X) to the wallet address of the transaction server 40 as a fee payment means.
The transaction including the contents of the sell order is approved and incorporated into the blockchain to formally complete the sell order.

FIG. 10 is a flowchart illustrating a board information generation / distribution process executed by the transaction server.
In step S111, the CPU 41 (sell order acquisition processing unit 51) determines whether or not it is the update timing of the board information.
When it is determined that it is the update timing (Yes in step S111), in step S112, the new transaction in which the order information is described in OP_RETURN is the blockchain network x of the virtual currency X in the CPU 41 (sell order acquisition processing unit 51). Judge whether or not it is published in.

If it is open to the public (Yes in step S111), the CPU 41 (sell order acquisition processing unit 51) sets the order information in OP_RETURN in the new transaction OP_RETURN in step S113 to sell order information (orderer's wallet address). , Order details) and store it in the order information storage unit 61.
Then, in step S114, the CPU 41 (board information generation processing unit 52) generates board information in which the order information acquired in step S113 is displayed in a list, stores it in the board information storage unit 62, and ends this processing.
In step S111, when it is determined that it is not the update timing of the board information (No in step S111), or when a new transaction in which the order information is described in OP_RETURN is not published (No in step S112), the CPU 41 (No in step S112). The distribution unit 53) determines in step S115 whether or not there is a request for board information from the terminal device.

When it is determined that the board information has been requested (Yes in step S115), the CPU 41 (board information distribution processing unit 53) requests the latest board information stored in the board information storage unit 62 in step S116. Deliver to the existing terminal device 10.
The process of searching the blockchain, acquiring the sell order information from the transaction including the sell order, and generating the board information can be performed not by the transaction server 40 but by each terminal device 10. In that case, The terminal device 10 monitors the blockchain at any time, acquires a transaction including a sell order when it is published, and reflects it in the board information.

By the way, among the sell orders displayed on the buy board (board information) 102, the digested sell orders need to be hidden from the buy board 102.
When the buy order using the buy board 102 made by the terminal device 10 is published, it may be deleted from the board information stored in the board information storage unit 62, or after the buy order is published, it may be deleted. When the atomic swap is normally completed (when the fourth transaction is published by the terminal device 10b on the buying side), the board information stored in the board information storage unit 62 may be deleted.

FIG. 11 is a flowchart illustrating a buy order process executed by the terminal device on the buying side.
In step S121, the CPU 11 (interface processing unit 21) determines whether or not the buy order operation has been performed by selecting the order content displayed on the buy plate 102 using the input device 17.
When it is determined that the buy order operation has been performed (Yes in step S121), the CPU 11 (buy order processing unit 23) describes the contents of the sell order selected on the buy board 102 as the buy order in OP_RETURN in step S122. Create a transaction for the buy order you made. A buy order transaction can be said to be a transaction that requests an atomic swap from a selling user. In addition, it is preferable to include the wallet address (public key, public key hash) of the user on the buying side as the content.
Then, the CPU 11 (buy order processing unit 23) performs the buy order processing by broadcasting the transaction created in step S122 in step S123.

When the user on the buying side "transfers" the virtual currency Y in exchange for the virtual currency X, the transaction is sent to, for example, the blockchain network y of the virtual currency Y.
At this time, the CPU 11 may broadcast a transaction for remittance of a predetermined fee (for example, virtual currency Y) to the wallet address of the transaction server 40 as a fee payment means.
The transaction including the contents of the buy order is approved and incorporated into the blockchain to formally complete the buy order.
By the above processing, the matching between the selling side and the buying side of the virtual currency is completed, and the preparation for atomic swap is completed.

FIG. 12 is a flowchart illustrating an atomic swap execution process executed by the terminal device on the selling side.
The terminal device on the selling side corresponds to the terminal device 10a here, and the CPU 11 in the description of FIG. 12 is the CPU 11 of the terminal device 10a.
In step S151, the CPU 11 (atomic swap execution processing unit 25) determines whether or not the transaction of the buy order corresponding to the sell order related to the sell order processing has been published.

If it is determined that the remittance has been made public (Yes in step S151), the CPU 11 (atomic swap execution processing unit 25) determines the remittance destination and the remittance amount based on the contents of the sell order and the buy order in step S152.
As the remittance destination, the public key of the other user or the address as the public key hash is input. Public keys are exchanged in advance.
The CPU 11 (atomic swap execution processing unit 25) determines a random value R in step S153, and calculates a hash value H of the value R in step S154.
The random value R may be automatically generated by the atomic swap execution processing unit 25, or may be configured to be determined and input by the selling user himself / herself.

Then, the CPU 11 (atomic swap execution processing unit 25) controls the hardware wallet in step S155, and uses the private key stored in the hardware wallet HW_A to digitally sign the user A for the first transaction Tx1. SigA1 is generated.
Then, the CPU 11 (atomic swap execution processing unit 25) creates the first transaction Tx1 with the electronic signature Sigma1 in step S156, and the CPU 11 (transaction transmission processing unit 64) creates the first transaction Tx1 in step S157. It is sent to the blockchain network y of the virtual currency Y.

After that, the CPU 11 (atomic swap execution processing unit 25) starts the search for the blockchain network x of the virtual currency X in step S158.
Then, in step S159, the CPU 11 (atomic swap execution processing unit 25) has a blockchain network x in which the second transaction Tx2 is the virtual currency X (by being created and approved by the terminal device 10b which is the counterparty of the currency exchange). Determine if it is published in. The second transaction Tx2 includes the hash value H.

The atomic swap execution processing unit 25 searches the data on the blockchain for a transaction including the hash value H and the public key (address) of the user A. As a result, the atomic swap execution processing unit 25 determines whether or not the second transaction Tx2 is open to the public on the blockchain.
Alternatively, the atomic swap execution processing unit 25 may receive the transaction ID of the second transaction Tx2 from the terminal device 10b. Then, the atomic swap execution processing unit 25 searches the data on the blockchain using the transaction ID of the received transaction Tx2. As a result, the atomic swap execution processing unit 25 determines whether or not the second transaction Tx2 is open to the public on the blockchain.

When it is determined that the second transaction Tx2 is not open (No in step S159), the CPU 11 (atomic swap execution processing unit 25) repeats the process of step S159 and waits for the release of the second transaction Tx2.
When it is determined that the second transaction Tx2 is open (Yes in step S159), the CPU 11 (atomic swap execution processing unit 25) controls the hardware wallet in step S160 and stores it in the hardware wallet HW_A. The private key is used to generate the electronic signature Sigma2 of the user A for the third transaction Tx3.
Then, the CPU 11 (atomic swap execution processing unit 25) creates the first transaction Tx1 with an electronic signature in step S161, and the CPU 11 (transaction transmission processing unit 64) virtualizes the third transaction Tx1 in step S162. It is sent to the blockchain network y of the currency Y.

FIG. 13 is a flowchart illustrating an atomic swap execution process executed by the terminal device on the buying side.
The terminal device on the buying side corresponds to the terminal device 10b here, and the CPU 11 in the description of FIG. 13 is the CPU 11 of the terminal device 10b.
The CPU 11 (atomic swap execution processing unit 25) sets the remittance destination and the remittance amount based on the buy order in step S171.
Then, the CPU 11 (atomic swap execution processing unit 25) determines in step S172 whether or not the first transaction Tx1 is open to the blockchain network y of the virtual currency Y.

The atomic swap execution processing unit 25 searches the data on the blockchain for a transaction including the public key (address) of the user A. As a result, the atomic swap execution processing unit 25 determines whether or not the first transaction Tx1 is open to the public on the blockchain.
Alternatively, the atomic swap execution processing unit 25 may receive the transaction ID of the first transaction Tx1 from the terminal device 10a. Then, the atomic swap execution processing unit 25 searches the data on the blockchain using the transaction ID of the received transaction Tx1. As a result, the atomic swap execution processing unit 25 determines whether or not the first transaction Tx1 is open to the public on the blockchain.
When it is determined that the first transaction Tx1 is open to the public (Yes in step S172), the CPU 11 (atomic swap execution processing unit 25) acquires the value of the hash value H included in the first transaction Tx1 in step S173. ..

Next, the CPU 11 (atomic swap execution processing unit 25) controls the hardware wallet HW_B in step S174, and uses the private key stored in the hardware wallet HW to perform a second transaction including the hash value H. The electronic signature Sigma B1 of the user B for Tx2 is generated.

The CPU 11 (atomic swap execution processing unit 25) creates a second transaction Tx2 with the electronic signature Sigma B1 generated in step S174 in step S175, and blocks the created second transaction Tx2 in the virtual currency Y in step S176. Send to the chain network y.

Next, the CPU 11 (atomic swap execution processing unit 25) starts the search for the blockchain network y in step S177.
In step S178, the CPU 11 (atomic swap execution processing unit 25) determines whether or not the third transaction Tx3 is open to the blockchain network y of the virtual currency Y.

The CPU 11 (atomic swap execution processing unit 25) can find the third transaction Tx3 from the blockchain by searching the entire corresponding blockchain and searching the transaction data including the public key (address) of the user B. ..
Alternatively, by receiving the transaction ID of the third transaction Tx3 from the terminal device 10a that created the third transaction Tx3, and searching for the transaction corresponding to the transaction ID, the third transaction Tx3 can be searched from the blockchain. You can.

When it is determined that the third transaction Tx3 is not open (No in step S178), the CPU 11 (atomic swap execution processing unit 25) repeats the process of step S178 and waits for the release of the third transaction Tx3.
When it is determined that the third transaction Tx3 is open to the public (Yes in step S178), the CPU 11 (network search processing unit 65) acquires the secret value R in the input of the third transaction Tx3 in step S179.

Then, the CPU 11 (atomic swap execution processing unit 25) controls the hardware wallet HW_B in step S180, and uses the private key stored in the hardware wallet HW to use the private key stored in the hardware wallet HW to include the value of R in the fourth transaction Tx4. The electronic signature SigmaB2 of the user B for use is generated.

The CPU 11 (atomic swap execution processing unit 25) creates a fourth transaction Tx4 with the electronic signature SigB2 generated in step S180 in step S181, and blocks the created fourth transaction Tx4 in the virtual currency Y in step S182. Send to the chain network y.

Atomic swaps such as those mentioned above have the disadvantage that it takes time to complete a transaction. The conclusion of a transaction is the completion of the process in which each user finally receives the virtual currency to be traded.
Therefore, even if the user wants to use the virtual currency obtained (planned to be obtained) by atomic swap for another transaction (perform a revolving transaction), the virtual currency will not be immediately available. ..
Therefore, in the system of the present embodiment, the transaction server 40 can provide credit using the virtual currency exchanged by the atomic swap as collateral, and can lend the virtual currency to both users.
More specifically, it monitors atomic swap transactions and lends cryptocurrencies for unapproved transactions as if they were canceled or remitted in equivalent consideration. Cancellation is the process of returning the virtual currency to its original owner after the expiration date of the withdrawal.
It is also possible to calculate the past transaction success probability of the user who has placed a sell order from the blockchain and determine the type and quantity of virtual currency to be credited.

FIG. 14 is a flowchart illustrating a transaction evaluation process executed by the transaction server.
In step S301, the CPU 41 (transaction evaluation processing unit 55) of the transaction server 40 determines whether or not it is the evaluation timing of the success probability of the atomic swap.
When it is determined that the evaluation timing is reached (Yes in step S301), the CPU 41 (transaction evaluation processing unit 55) searches the blockchain network in step S302 and all transactions of the atomic swap started by a specific user. Tx1 (including the hash value H) is collected, and in step S303, the found transaction Tx1 is counted for each user.

Next, in step S304, the CPU 41 (transaction evaluation processing unit 55) searches the blockchain network and collects all transactions Tx3 (including disclosure of the value R) of the atomic swap initiated by a specific user. In step S305, the found transaction Tx3 is counted for each user.
If all atomic swaps initiated by a particular user are successfully initiated, the number of first transaction Tx1 published by that user and the number of third transaction Tx3 should match.
If they do not match, the user suspends the atomic swap without disclosing the random value R, and as a result, the trading partner has not received the virtual currency either.

In step S306, the CPU 41 (transaction evaluation processing unit 55) determines the ratio of the number of third transactions Tx3 counted in step S305 to the number of first transactions Tx1 counted in step S303 as the "success probability" of the user. Calculate as.
Then, in step S307, the CPU 41 associates the success probability calculated in step S306, the number of successes counted in step S305, and the number of trials (parameter) counted in step S303 with each user in the transaction evaluation storage unit 63. Store.
In the flowchart of FIG. 14, all past atomic swap transactions are collected for a specific user, but this is a process required only for the first evaluation, and the transaction evaluation timing after the next time. , It is possible to acquire only the transactions of atomic swaps newly generated after the first time and add them to the past transactions to calculate the transaction success probability.

The process of FIG. 14 calculates (evaluates) the transaction success probability of all users who have performed (started) atomic swap on the blockchain network.
Depending on this method, a specific user first places a sell order using the mechanism of the present embodiment, and from the time when the sell order is displayed on the buy board of the present embodiment, the user's past transaction success You can display all the probabilities and the number of successes.
On the other hand, tracking transaction history for all users can be said to be problematic in terms of processing load and amount of information to be managed. This is because the information of the user who does not use the mechanism of this embodiment is considered to be useless.
Therefore, in the post-trading matching process shown below, only the transaction success probability of the selling side user appearing on the buying board 102 is evaluated based on the success or failure of the atomic swap started from the buying board 102. good.
As a result, the load of searching the blockchain and the amount of information on the transaction success probability for each user can be significantly reduced.

FIG. 15 is a flowchart illustrating a process executed by the transaction server after the establishment of trading matching.
The CPU 41 (buy order notification processing unit 54) searches the blockchain network in step S401 and determines whether or not the transaction of the buy order corresponding to the sell order included in the board information has been published.
If it is determined that such a transaction has been published (Yes in step S401), the CPU 41 (buy order notification processing unit 54) has described the notification destination (IP address, URL) in OP_RETURN of the sell order in step S402. Judge whether or not.
If it is determined that there is no description of the notification destination (No in step S402), the CPU 41 proceeds to the process in step S404.

When it is determined that the notification destination is described (Yes in step S402), the CPU 41 (buy order notification processing unit 54) notifies the described notification destination that there is a buy order in step S403.
When a sell order is placed on the selling side terminal device 10a and then a buy order is placed on the buying side terminal device 10b, atomic swap may be started if the selling side terminal device is offline. Can not.
Therefore, in the transaction server 40 of the present embodiment, when a buy order is placed from the board information, the notification destination (IP address, URL) described in OP_RETUN of the corresponding sell order is notified. Encourage the seller's device to go online.
By controlling in this way, when a buy order is placed using the board information, the terminal device (wallet) for which the sell order is placed can be reliably brought online and a transaction can be started smoothly.

After that, the CPU 41 (credit / loan processing unit 56) determines in step S404 whether or not the first transaction Tx1 of the atomic swap is disclosed by the terminal device 10a on the selling side.
When it is determined that the first transaction Tx1 has been published (Yes in step S404), the CPU 41 (credit / loan processing unit 56) determines whether or not the second transaction Tx2 has been published by the terminal device 10b on the buying side in step 405. To judge.
When it is determined that the second transaction Tx2 has been published (Yes in step S405), the CPU 41 (credit / loan processing unit 56) determines whether or not the third transaction Tx has already been published by the terminal device 10a on the selling side in step S406. To judge.

If it is determined that the third transaction Tx3 has already been published (Yes in step S406), the process ends as it is.
When it is determined that the third transaction Tx3 has not been published yet (No in step S405), it is considered that the fourth transaction Tx4 has not been published as a matter of course.
In this state, the virtual currency "sent" by both users due to atomic swap is retained, and neither user has received it.

In such a state, the CPU 41 (credit / loan processing unit 56) lends the virtual currency to be loaned and the loan based on the success probability of the atomic swap of the selling user evaluated in the process of FIG. 14 in step S407. Determine the amount. Lending virtual currency is the process of remittance of virtual currency to users on the selling side and users on the buying side according to the loan amount.
The standard for determining the virtual currency to lend and the loan amount is the success probability of the user who is the "seller" in this transaction. In this embodiment, it is the selling user who determines the random value R and has the initiative in the transaction. Since the success or failure of the atomic swap depends on whether or not the selling user publishes the third transaction Tx3 including the value of R, the transaction is evaluated based on the success probability of the selling user.

The process of determining the type and quantity of virtual currency to be lent will be described by taking as an example the process of exchanging Bitcoin on the selling side and Litecoin on the buying side.
<First example>
If the past transaction success probability of the selling side user who has placed a Bitcoin selling order is, for example, 60%, the transaction server 40 (credit / loan processing unit 56) will give the selling side user a Litecoin. Lend Litecoin up to the transaction volume. This is because there is a relatively high probability (60%) that the atomic swap will be successful and the seller will receive Litecoin in exchange for Bitcoin. The Litecoin transaction quantity is the quantity of Litecoin exchanged for Bitcoin specified in the sell order and the corresponding buy order.

Then, the transaction server 40 (credit / loan processing unit 56) lends bitcoins to the buying side up to the transaction quantity of bitcoins. This is because the atomic swap is successful and the buyer is likely to receive Bitcoin in exchange for Litecoin (60%). The Bitcoin transaction quantity is the quantity of Bitcoin exchanged for Litecoin specified in the sell order and the corresponding buy order.
In the credit / loan processing of this example, if the past transaction success probability of the selling user exceeds 50%, it is relatively likely that an atomic swap will be established and each other will receive the desired virtual currency, so the order will be placed. The virtual currency to be received in the transaction is remitted in advance (before the transaction is completed) up to the quantity made.
On the contrary, if the past transaction success probability of the selling user is 50% or less (less than), there is a relatively high possibility that the atomic swap will not be established. In that case, the virtual currency loan (remittance) itself may not be performed. Alternatively, assuming that the transaction is canceled, the virtual currency (in this example, Bitcoin on the selling side and Litecoin on the buying side) that is the source of the transaction on the selling side and the buying side is traded. It may be lent to each user on the selling side and the buying side up to the quantity.

<Second example>
Further, the conditions may be set more finely than in the above <first example>.
That is, when the past transaction success probability of the selling side user who has placed a Bitcoin sell order is 60%, the transaction server 40 (credit / loan processing unit 56) sells to the selling side user. Litecoin is lent up to 60% of the transaction volume of Litecoin specified in the order and the corresponding buy order, and Bitcoin is lent up to 40% of the transaction volume of Bitcoin.
On the other hand, the transaction server 40 (credit / loan processing unit 56) lends bitcoin to the buyer side up to 60% of the transaction volume of Bitcoin and 40% of the transaction volume of Litecoin. Lend Litecoin to the upper limit.
According to the past performance of the selling user, the selling user has a 60% chance of successfully trading and getting Litecoin, and a 40% chance of regaining the original Bitcoin. It is considered that the user on the selling side has a 60% probability of successfully trading and obtaining Bitcoin, and a 40% probability of regaining the original Litecoin.
Based on this probability, the virtual currency and quantity to be lent to both the selling side and the buying side users are determined.

In <1st example> and <2nd example>, when the transaction fee is taken, the upper limit of the lending quantity of virtual currency is set as the above transaction quantity by subtracting the quantity corresponding to the transaction fee from the transaction quantity. You may calculate and lend the virtual currency.
Returning to the description of the flowchart, in step S408, the CPU 41 broadcasts a transaction for remittance of the amount of virtual currency determined in step S407 to the selling user.
Then, in step S409, the CPU 41 of the transaction server 40 broadcasts a transaction for remittance of the amount of virtual currency determined in step S407 to the user on the selling side.

With the above configuration, in the virtual currency trading device of the present embodiment, in the atomic swap where the transaction speed is slow, before the atomic swap succeeds and receives the virtual currency, the virtual currency is borrowed in advance and another It can be used for transactions.
In addition, even if the atomic swap is canceled, the virtual currency can be received quickly and used for another transaction without wasting the time until the transaction actually times out and the original can be regained.
By making such a thing possible, the usability and convenience of virtual currency can be dramatically improved.

FIG. 16 is a diagram showing board information reflecting the transaction success probability of the user who placed the sell order.
Regarding users A to F shown in FIGS. 6 and 7, it is assumed that the past transactions of each user are evaluated as follows in the process of FIG.
That is, the user A succeeds in the atomic swap that has been tried 100 times 50 times, and the success probability is 50%.
In addition, the user B has succeeded in the atomic swap that has been tried 40 times 12 times, and the success probability is 30%.
In addition, the user C succeeds in the atomic swap tried 5 times 5 times, and the success probability is 100%.
In addition, the user D succeeds in the atomic swap tried 30 times 15 times, and the success probability is 50%.
In addition, the user E succeeds in the atomic swap 30 times, and the success probability is 100%.
In addition, the user F has succeeded in atomic swaps that have been tried 70 times 42 times, and the success probability is 60%.

Then, as shown in FIG. 16, the success probability, the number of successes, and the number of trials are additionally displayed on the sell order included in the board information displayed on the buy board 102.
In this case, in the board information generated by the distribution server 40, for example, as shown in FIG. 16, the sell orders are ordered in descending order of success probability, from user E → user C → user F → user A → use. It may be displayed in the order of person D → user B. If the success rates are the same, the sell orders of the users with the highest number of successes are displayed above.
Further, instead of the success probability, the sell order of the user who has a large number of successes may be displayed above.
As described above, not only the transaction conditions (exchange rate) but also the probability that the atomic swap will succeed can be visually recognized on the buying board 102, so that it is possible to judge a preferable transaction and greatly enhance the convenience of the transaction. ..

10 Terminal device, 11 CPU, 12 RAM, 13 Drive device, 14 Recording medium, 15 Network I / F, 16 External IO I / F, 17 Input device, 18 Display device, 21 Interface processing unit, 22 Order processing unit, 23 Order processing unit, 24 board information display processing unit, 25 atomic swap execution processing unit, 25a R value determination processing unit, 25b hash processing unit, 25c transaction creation processing unit, 25d electronic signature generation processing unit, 25e transaction transmission processing unit, 25f Network search processing unit, 30 minor equipment, 30x minor equipment, 30y minor equipment, 40 transaction server, 41 CPU, 42 RAM, 43 HDD, 50 blockchain monitoring processing unit, 51 order acquisition processing unit, 52 board information generation processing unit, 53 board information distribution processing unit, 54 order notification processing unit, 55 transaction evaluation processing unit, 56 credit / loan processing unit, 61 order information storage unit, 62 board information storage unit, 63 transaction evaluation storage unit, 64 transaction transmission processing unit, 65 Network search processing unit, 100 buy / sell order screen, 101 order column, 102 buy board

Claims (11)

A virtual currency trading device that conducts transactions for exchanging a first virtual currency and a second virtual currency.
An input means for inputting an order content specifying the quantity of the second virtual currency to be exchanged with the first virtual currency in the quantity desired by the user of the virtual currency trading device.
A sell order sending means for sending a sell order of the first virtual currency to the network, including the order contents input by the input means, and a sell order sending means.
A board information display means for displaying board information including sell orders sent to the network,
With
In the transaction, the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the second virtual currency remittance to the one user are received. The first remittance information including the first receipt information indicating the above, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the first remittance sent to the other user. The second receipt information, which indicates the receipt of one virtual currency, is published on the network.
The board information display means
The board that gives the possibility of success of the transaction related to the user based on the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. Display information,
A virtual currency trading device characterized by that. In the virtual currency trading device according to claim 1,
A selection means for selecting a desired sell order from the sell orders displayed by the board information display means, and
A buy order sending means for sending a buy order of the first virtual currency to be exchanged for the second virtual currency to the network, including information related to selection of a sell order by the selection means, and a buy order sending means.
When a buy order corresponding to the sell order is published on the network by another virtual currency trading device, a transaction execution means for disclosing the first remittance information and starting the transaction with the other virtual currency trading device. When,
A virtual currency trading device characterized by being equipped with. In the virtual currency trading device according to any one of claims 1 or 2.
When the sell order is sent by the sell order sending means,
A virtual currency trading device comprising a fee payment means for sending remittance information to a predetermined remittance destination and indicating remittance of virtual currency corresponding to the fee to a network. In the virtual currency trading device according to any one of claims 1 to 3,
The sell order sending means is a virtual currency trading device, characterized in that, when sending the sell order, the notification destination information related to the virtual currency trading device that placed the sell order is included in the order content and sent. A transaction server device that mediates virtual currency transactions between multiple virtual currency trading devices.
Each virtual currency trading device sends a sell order and a buy order specifying the exchange quantity of virtual currency to the network, and sends them to the network.
The transaction shows the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the receipt of the second remittance of the second virtual currency sent to the one user. The first remittance information, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the first remittance sent to the other user. The second receipt information, which indicates the receipt of virtual currency, is made public on the network.
A board information generating means that generates board information according to a sell order sent to the network,
A board information distribution means for distributing the board information to the virtual currency trading device,
A lending means for lending the second virtual currency to the one user during the execution of the transaction according to the quantity of the second virtual currency related to the second remittance information.
Evaluation that evaluates the possibility of success of the transaction related to the user according to the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. With means,
The lending means is a transaction server device characterized in that the quantity of virtual currency to be lent is determined according to the evaluation result by the valuation means. In the transaction server device according to claim 5.
The lending means
A transaction server device characterized in that the first virtual currency is lent to the other user according to the quantity of the first virtual currency related to the first remittance information. A transaction server device that mediates virtual currency transactions between multiple virtual currency trading devices.
Each virtual currency trading device sends a sell order specifying the exchange quantity of the second virtual currency for the first virtual currency to the network, and sends a buy order corresponding to the sell order to the network.
In the transaction, the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the second virtual currency remittance to the one user are received. The first remittance information including the first receipt information indicating the above, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the first remittance sent to the other user. The second receipt information, which indicates the receipt of one virtual currency, is published on the network.
A board information generating means that generates board information according to a sell order sent to the network,
A board information distribution means for distributing the board information to the virtual currency trading device,
Evaluation that evaluates the possibility of success of the transaction related to the user according to the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. Means and
With
The board information generating means is a transaction server device characterized in that the evaluation result of a user related to the sell order is added to the board information according to the evaluation result by the evaluation means. In the transaction server device according to claim 7.
The sell order includes notification destination information related to the virtual currency trading device that placed the sell order.
The transaction server device is characterized by comprising a notification means for notifying a notification destination indicated by the notification destination information when a buy order corresponding to a sell order published on the network is placed. A plurality of virtual currency trading devices that perform transactions for exchanging a first virtual currency and a second virtual currency,
A virtual currency trading system equipped with a trading server device.
In the transaction, the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the second virtual currency remittance to the one user are received. The first remittance information including the first receipt information indicating the above, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the first remittance sent to the other user. The second receipt information, which indicates the receipt of one virtual currency, is published on the network.
The virtual currency trading device is
An input means for inputting an order content specifying the quantity of the second virtual currency to be exchanged with the first virtual currency in the quantity desired by the user of the virtual currency trading device.
A sell order sending means for sending a sell order of the first virtual currency to the network, including the order contents input by the input means, and a sell order sending means.
A board information display means for displaying board information including sell orders sent to the network,
With
The transaction server device is
A board information generating means for generating board information according to a sell order sent to the network, and
The possibility of success of the transaction related to the user is evaluated according to the number of the first received information with respect to the number of the first remittance information related to the specific user published on the network. Evaluation means and
According to the evaluation result by the evaluation means, the board information distribution means that adds the evaluation result of the user related to the sell order to the board information and distributes the board information to the virtual currency trading device.
With
Said plate information display means of the virtual currency transaction apparatus displays the board information delivered by said plate information distribution means,
A virtual currency trading system characterized by that. It is a virtual currency trading method of a virtual currency trading device provided with an input means, a sell order sending means, and a board information display means, and performing a transaction for exchanging a first virtual currency and a second virtual currency.
In the transaction, the first remittance information including specific information indicating the remittance of the first virtual currency from one user and the second virtual currency remittance to the one user are received. The first remittance information including the first receipt information indicating the above, the second remittance information including the specific information indicating the remittance of the second virtual currency from another user, and the first remittance sent to the other user. The second receipt information, which indicates the receipt of one virtual currency, is published on the network.
The step of causing the input means to input the order contents specifying the quantity of the second virtual currency to be exchanged with the first virtual currency in the quantity desired by the user of the virtual currency trading device.
A step in which the sell order sending means sends a sell order of the first virtual currency to the network including the order contents input by the input means.
The board information display means succeeds in the transaction relating to the user based on the number of the first received information relative to the number of the first remittance information relating to the specific user published on the network. The step of displaying the board information including the sell order sent to the network, which is the board information to which the possibility is given, and
A cryptocurrency trading method characterized by including. A program that causes a computer to execute the virtual currency transaction method according to claim 10.

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