TWI804707B - Method and device for preventing a double spend attack and a computer readable memory medium - Google Patents

Abstract

A method for preventing double-spend attacks, including: acquiring transaction information to be traded, the transaction information including a virtual currency type and a transaction quantity; acquiring a currency price according to the virtual currency type; acquiring a transaction value according to the transaction quantity and the currency price; acquiring a unit attack cost of a corresponding blockchain network according to the virtual currency type; adjusting the number of initial confirmations so that the total attack cost is greater than the transaction value, the total attack cost being equal to the initial confirmation times multiplied by the unit attack cost; and submitting a transaction information to the blockchain network. This application also provides a device for preventing double-spend attacks. This application dynamically adjusts the number of confirmations according to the transaction values so that the cost of double-spend attacks is greater than the transaction value, thereby the double-spend attacks can be prevented.

Description

Method, device and computer-readable storage medium for preventing double-spend attack

The invention relates to the technical field of block chains, in particular to a method, device and computer-readable storage medium for preventing double-spending attacks.

The double spending attack (Double Spending) of encrypted currency (such as BTC) transactions in the blockchain field, in simple terms, is that after the attacker realizes the transaction on the exchange, he premeditatedly controls the computing power to rewrite the block, so that the previous The blockchain transaction is invalidated, but the attacker has cash. Specifically, most exchanges determine a fixed number of confirmations based on different currencies. When the transaction amount is large, cyber attackers will add more than 51% of the blockchain computing power in the confirmation process, and they can trade in this relatively large amount. Within a short confirmation period, master the accounting rights of the entire block chain, tamper with the block transaction content, and withdraw the computing power from the block chain after the exchange confirms that the encrypted currency transaction is a trustworthy transaction , so that the transaction of the encrypted currency fails, so that the encrypted currency returns to the attacker, thus completing a double-spend attack. If the double-spend attack cannot be avoided, it will cause losses to the exchange or the recipient of the encrypted currency, and disrupt the transaction order of the encrypted currency.

In view of this, the present invention proposes a method, device, and computer-readable storage medium for preventing double-spend attacks to solve the above-mentioned problems.

The first aspect of the present application provides a method for preventing double-spending attacks, including: obtaining transaction information to be traded, the transaction information including virtual currency type and transaction quantity; obtaining currency price according to the virtual currency type; according to the transaction The quantity and the currency price obtain the transaction value; obtain the unit attack cost of the corresponding blockchain network according to the virtual currency type; adjust the number of initial confirmations so that the total attack cost is greater than the transaction value, wherein the total attack cost It is equal to the number of times of initial confirmation multiplied by the unit attack cost; submitting the transaction information to the blockchain network.

Further, after submitting the transaction information to the blockchain network, it also includes: obtaining the number of completion confirmations; judging whether the number of completion confirmations reaches the initial number of confirmations: if yes, then judging that the transaction is completed.

Further, if it is determined that the number of completed confirmations has not reached the initial number of confirmations, it is determined whether there is error information in the transaction process: if yes, the transaction is terminated and a warning message is issued.

Further, the "obtaining the number of completed confirmations" specifically includes: obtaining the query time period according to the operation time; and sequentially obtaining the confirmation completion times according to the query time period.

Further, the method further includes the steps of: updating the transaction progress according to the confirmed completion times; and displaying the transaction progress in real time.

Further, obtaining the unit attack cost of the corresponding blockchain network according to the virtual currency type specifically includes the steps of: obtaining the total computing power value of the corresponding blockchain network according to the virtual currency type; The unit computing power cost; calculate the computing time of each block of the blockchain network; obtain the unit attack cost according to the computing time and the unit computing power cost; or obtain the corresponding The maximum computing power value of a single blockchain node in the blockchain network; calculate the unit computing power cost of the blockchain network; calculate the computing time of each block of the blockchain network; according to the The maximum computing power value, the unit computing power cost and the computing time are used to obtain the unit attack cost.

Further, the method also includes the step of periodically obtaining the currency price, the The total computing power value, the unit computing power cost, the computing time and the maximum computing power value of a single blockchain node in the blockchain network; if the currency price, the total computing power value, the When one or more of the unit computing power cost, the computing time, or the maximum computing power value of a single blockchain node in the blockchain network changes, the number of initial confirmations is correspondingly adjusted.

Further, the method further includes the step: if the computing power value of at least one trusted blockchain node in the blockchain network is greater than the computing power value of other blockchain nodes, then adjusting the number of initial confirmations to basic confirmation frequency.

The second aspect of the present application provides a device for preventing double-spending attacks, including: a memory, on which several computer programs are stored; a processor, when the processor is used to execute the computer programs stored in the memory Steps for realizing the method for preventing double-spending attacks.

The third aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for preventing double-spending attacks is implemented.

The present invention dynamically adjusts the number of confirmations based on the transaction value, so that the total attack cost of double-spending attacks is greater than the transaction value, thereby realizing the prevention of double-spending attacks, and by adjusting the number of confirmations together, the security of large-amount transactions and the convenience of small-amount transactions are guaranteed .

100: A device to prevent double-spending attacks

10: Processor

20: memory

30: Display unit

40: Speech unit

50: input unit

200: A system for preventing double-spending attacks

201: Get the module

202: Operation module

203: Adjustment module

204: Trading Module

205:Update module

206: Display module

207: Judgment module

208:Alarm module

FIG. 1 is a schematic diagram of the hardware architecture of a device for preventing double-spending attacks in an embodiment of the present invention.

FIG. 2 is a schematic diagram of functional modules of a system for preventing double-spending attacks in an embodiment of the present invention.

Fig. 3 is a flowchart of a method for preventing double-spending attacks in an embodiment of the present invention.

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

In the following description, many specific details are set forth in order to fully understand the present invention, and the described embodiments are only a part of the embodiments of the present invention, but not all of them. Based on the implementation manners in the present invention, all other implementation manners obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

As used herein, the term "and/or" includes any and all combinations of one or a plurality of the associated listed items.

Please refer to FIG. 1 , which is a schematic diagram of a device for preventing double-spending attacks provided in an implementation of the present invention.

In this embodiment, the device 100 for preventing double-spending attacks includes a processor 10 , a memory 20 , a display unit 30 , a voice unit 40 and an input unit 50 .

The processor 10 can be a central processing unit (CPU, Central Processing Unit), and can also include other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC) , Ready-made programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. General-purpose processor can be microprocessor or this processor also can be any conventional processor etc., described processor 10 is the control center of the device 100 of preventing double-spending attack, utilizes various interfaces and lines to connect the whole preventing double-spending attack various parts of the device 100.

The memory 20 is used to store various data in the device 100 for preventing double-spending attacks, such as image sets, image models, and the like. In this embodiment, the memory 20 may include but not limited to a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a programmable read-only memory (Programmable Read -Only Memory, PROM), Erasable Programmable Read-Only Memory (EPROM), One-time Programmable Read-Only Memory (OTPROM), electronic Erasable rewritable read-only memory (Electrically-Erasable Programmable Read-Only Memory, EEPROM), CD-ROM (Compact Disc Read-Only Memory, CD-ROM) or other optical disk memory, disk memory, tape memory media, or any other computer-readable medium that can be used to carry or store data.

The display unit 30 is used to display various information processed by the processor 10 , such as displaying transaction progress, and the display unit 30 can be a monitor, a touch screen, or the like.

The voice unit 40 is used to play various information processed by the processor 10, such as playing transaction progress and warning prompts. The voice unit 40 is a speaker or other voice equipment.

The input unit 50 is used for inputting various information, and the input unit 50 can be a keyboard, a touch screen, and the like.

In one embodiment, the processor 10 , the memory 20 , the display unit 30 , the voice unit 40 and the input unit 50 can be integrated into a computer device. In other embodiments, the display unit 30 , the voice unit 40 and the input unit 50 can also be omitted.

The device 100 for preventing double-spending attacks may be computing devices such as desktop computers, notebooks, palmtop computers, and cloud servers. Those skilled in the art can understand that the schematic diagram is only an example of the device 100 for preventing double-spend attacks, and does not constitute a limitation to the device 100 for preventing double-spend attacks, and may include more or less components than those shown in the illustration, or Combining certain components or different components, for example, the apparatus 100 for preventing double-spending attacks may also include network access devices, bus bars, and the like.

Please refer to FIG. 2 , which is a schematic diagram of functional modules of a system 200 for preventing double-spending attacks in an embodiment of the present invention.

In this embodiment, the system 200 for preventing double-spending attacks includes one or more computer instructions in the form of programs, and the one or more computer instructions in the form of programs are stored in the memory 20 and processed by the 10 to implement the functions provided by the present invention.

In this embodiment, the system 200 for preventing double-spending attacks can be divided into an acquisition module 201, an operation module 202, an adjustment module 203, a transaction module 204, an update module 205, a display module 206, a judgment module Module 207 and alarm module 208. The functions of each functional module will be described in detail in the following embodiments.

The acquiring module 201 is used to acquire transaction information to be traded. The transaction information includes the virtual currency type and transaction quantity.

In one embodiment, the information input by the input unit 50 is acquired by calling the input unit 50 .

The obtaining module 201 is also used to obtain currency prices according to the type of virtual currency.

Among them, the currency price can be the actual price, that is, the transaction price at this moment, or the estimated price, that is, the average value of the transaction price within a period of time.

In one embodiment, the currency prices of multiple trading platforms in a preset period of time are obtained; the average price is calculated to obtain the average price, wherein the average price is the required currency price.

The calculation module 202 is used to obtain the transaction value according to the transaction quantity and currency price. Wherein the transaction value is the actual value of the virtual currency traded, and the transaction value is equal to the transaction quantity multiplied by the currency price.

The obtaining module 201 is also used to obtain the total computing power value of the corresponding blockchain network according to the currency type.

Among them, computing power (also known as hash rate) is the unit of measurement for the processing power of the blockchain network, that is, the speed at which the computer (CPU) calculates the output of the hash function.

The total computing power value of the blockchain network can be the actual computing power value at this moment, the average computing power value in the past period of time, or the estimated power value; the actual computing power value can be obtained directly and The specific acquisition method is not limited. For example, the current computing power value can be estimated according to the time spent in the competition for absenteeism and bookkeeping rights in the blockchain network within the preset time and the difficulty of bookkeeping; it can also detect the computing power of all mining machines on the blockchain network to obtain The current computing power value of the overall blockchain network.

The computing module 202 is also used to calculate the unit computing power cost according to the total computing power value.

Specifically, the unit computing power value is obtained according to the total computing power value, and the unit computing power cost is calculated based on the unit computing power value, hardware cost, electricity cost, etc., where the hardware cost is the purchase cost or lease cost of the mining machine, and the electricity cost The electricity cost for using the mining machine.

Furthermore, the unit cost of computing power also includes technology cost, labor cost, maintenance cost, etc.

The calculation module 202 is also used to calculate the calculation time of each block in the blockchain network.

Among them, taking the Bitcoin blockchain network as an example, the Bitcoin blockchain creates a block in about 10 minutes and broadcasts it to all nodes in the entire network. However, due to the limited computing power of the Bitcoin blockchain network Fluctuations, the creation time of new blocks will be different, for example, 10 minutes and 30 seconds, 9 minutes and 30 seconds.

Wherein, the calculation time may be the establishment time of the latest block, or the average value of the establishment time of multiple blocks in the latest time period.

The computing module 202 is also used to obtain the unit attack cost according to the computing time and the unit computing power cost.

For example, if the blockchain network includes 100 total computing power, the attacker initiates a double-spend attack, at least controlling more than 50% of the computing power in the blockchain network, such as 51 computing power, the trader initiates a After the transaction, the trader sends a real transaction ticket to the entire blockchain network, and the attacker generates a fake transaction ticket, and uses the principle of "minority obeys the majority" in the consensus mechanism to replace the real transaction ticket with the fake transaction ticket and write In the block of the main blockchain, the real transaction order will be deleted or tampered with by other target service nodes. The double spend The unit attack cost required for the attack is P0=p1*51*p2, p1 is the time required for successful confirmation of each successful transaction, that is, the time required for each new block to be established, and p2 is the cost per unit of computing power.

The operation module 202 is also used to obtain the maximum computing power value of a single blockchain node in the corresponding blockchain network according to the virtual currency type; calculate the unit computing power cost of the blockchain network; calculate the area The computing time of each block in the block chain network; the unit attack cost is obtained according to the maximum computing power value, the unit computing power cost and the computing time.

Specifically, obtain the maximum computing power value of a single blockchain node in the corresponding blockchain network, the unit computing power cost and the computing time, then the blockchain node with the maximum computing power value has the ability to obtain the The maximum probability of the accounting right in the blockchain network is the highest, and the unit attack cost of the attacker should not be less than the cost of the node with the maximum computing power value, that is, the unit attack cost should not be less than the maximum computing power value multiplied by Unit computing power cost and computing time.

The adjustment module 203 is used to adjust the number of initial confirmations so that the total attack cost is greater than the transaction value.

The total attack cost is equal to the multiplication of the initial confirmation times by the unit attack cost.

The confirmation indicates that the transaction is recorded and confirmed by the blockchain network. If the initial number of confirmations is N, when the transaction occurs, the block recording the transaction will be confirmed for the first time, and the chain after the block will be confirmed for the first time. N-1 confirmations are performed on each block above. All these confirmations and transactions are time-stamped on the blockchain, making them irreversible and immutable. If the number of initial confirmations is reached, it can be judged that the transaction is successful.

Adjust the number of initial confirmations based on the unit attack cost and transaction value, so that the total attack cost is greater than the transaction value. The total cost of the double-spending attack is P, where P=P0*N and P>M, where N is the number of confirmations, and M is the transaction value.

In another embodiment, the adjustment module 203 is also used to obtain the currency price, the total computing power value, the unit computing power cost, the computing time, and the individual computing power in the blockchain network according to the cycle. The maximum computing power value of the blockchain node, if the currency price, the total computing power value, the unit computing power cost, the computing time or the maximum value of a single blockchain node in the blockchain network If one or more of the computing power values change, the number of initial confirmations will be adjusted accordingly.

Due to the relatively long trading time of blockchain virtual currency, there are many factors that affect the transaction value during this trading time period, such as skyrocketing virtual currency prices, fluctuations in mining machine rent, electricity bill adjustments, and surges in total computing power. The virtual currency price is calculated to obtain the transaction value or unit attack cost, and adjust the number of initial confirmations according to the transaction value or unit attack cost, so that the total attack cost is greater than the transaction value. The cycle can be adjusted according to the capability of the equipment and the price fluctuation of the virtual currency within the time period. For example, the cycle can be five minutes.

In another embodiment, if the computing power of at least one trusted blockchain node in the blockchain network is greater than the computing power of other blockchain nodes, the adjustment module 203 is also used to adjust the number of initial confirmations to the basic number of confirmations. The number of basic confirmations is the minimum number of confirmations for the completion of a transaction. For example, if at least six confirmations are required by the blockchain network or an exchange to complete a transaction, then the number of basic confirmations is 6. Among them, trusted blockchain nodes can be traders Its own blockchain node can also be other blockchain nodes trusted by traders.

Further, the number of initial confirmations is not less than the number of basic confirmations.

The transaction module 204 is used to submit transaction information to the blockchain network.

Specifically, the transaction information is broadcast to the blockchain network, so that a new block records the transaction information.

The obtaining module 201 is also used to obtain the confirmation completion times.

Specifically, obtain the newly created block information of the blockchain network after the broadcast information is released, and then obtain the corresponding confirmation completion times.

In an embodiment, the query time period is obtained according to the operation time, and the confirmation completion times are sequentially obtained according to the query time period.

Specifically, the Bitcoin blockchain takes about 10 minutes to create a block, so the first confirmation can be queried in the first 10 minutes, and the second confirmation can be queried in the second 10 minutes. Update time, reduce waiting time, save server computing resources, and reduce costs.

The updating module 205 is used for updating the transaction progress according to the confirmation completion times.

For example, the transaction progress is calculated by the completed number of confirmations. For example, if the number of confirmations is 5 and the number of completed confirmations is 1, then the transaction progress is 20%.

The display module 206 is used for real-time display of transaction progress.

In one embodiment, the transaction progress is displayed by a progress bar or a progress value.

The judging module 207 is used for judging whether the number of confirmation completions reaches the initial number of confirmations.

Specifically, it is judged whether the number of newly added blocks in the blockchain network is equal to the number of initial confirmation times.

The judging module 207 is also used for judging whether there is error information in the transaction process.

In one embodiment, the wrong information is that the malicious node tampers with the transaction information recorded in the block. For example, the transaction information issued by the trader is "A transfers the virtual currency to B", and the malicious node modifies the transaction information in the block as "A transfers the virtual currency to A".

The transaction module 204 is also used to terminate transactions.

In one embodiment, when the number of completed confirmations reaches the initial number of confirmations, the blocks in the block chain generate error information, such as malicious nodes tampering with transaction information, the transaction module 204 terminates the ongoing transaction to avoid property loss, that is, the block If the transaction fails in the chain network, the offline transaction or the transaction associated with the virtual currency will be terminated. For example, if the virtual currency is not received, the transfer to the trader will be stopped.

The alarm module 208 is used for sending alarm information.

In one embodiment, the alarm module 208 plays the alarm information by invoking the voice unit 40 .

Please refer to FIG. 3 , which is a flow chart of preventing double-spending attacks provided by an embodiment of the present invention. According to different requirements, the order of the steps in the flowchart can be changed, and some steps can be omitted. For ease of description, only parts related to the embodiments of the present invention are shown.

As shown in Fig. 3, the method for preventing double-spending attack includes the following steps.

Step S1: Obtain transaction information.

The transaction information is information to be traded, and the transaction information includes virtual currency type and transaction quantity.

Wherein said virtual currency is Bitcoin, Ether, etc., but not limited thereto.

In one embodiment, the transaction information also includes a transaction price, which is the price proposed by the buyer or seller of the virtual currency for the virtual currency. It can be understood that the price may not match the price set by each trading platform.

Step S2: Obtain the currency price according to the virtual currency type.

Among them, the currency price can be the actual price, that is, the transaction price at this moment, or the estimated price, that is, the average value of the transaction price within a period of time.

In one embodiment, step S2 specifically includes the steps of: obtaining currency prices of multiple trading platforms in a preset time period; calculating multiple currency prices to obtain an average price, wherein the average price is the required currency price.

Step S3: Obtain a transaction value according to the transaction quantity and the currency price.

Wherein the transaction value is the actual value of the virtual currency traded, which is equal to the transaction quantity multiplied by the currency price.

Step S4: Obtain the total computing power value of the corresponding blockchain network according to the currency type.

Among them, computing power is the unit of measurement for the processing power of the Bitcoin network, that is, the speed at which the computer calculates the output of the hash function.

The total computing power value of the blockchain network can be the actual computing power value at this moment, the average computing power value in the past period of time, or the estimated power value; the actual computing power value can be obtained directly and The specific acquisition method is not limited. For example, the current computing power value can be estimated according to the time spent in the competition for absenteeism and bookkeeping rights in the blockchain network within the preset time and the difficulty of bookkeeping; it can also detect the computing power of all mining machines on the blockchain network to obtain The current computing power value of the overall blockchain network.

Step S5: Calculate the unit computing power cost according to the total computing power value.

Specifically, the unit computing power value is obtained according to the total computing power value, and the unit computing power cost is calculated based on the unit computing power value, hardware cost, electricity cost, etc., where the hardware cost is the purchase cost or lease cost of the mining machine, and the electricity cost The electricity cost for using the mining machine.

Furthermore, the unit cost of computing power also includes technology cost, labor cost, maintenance cost, etc.

Step S6: Calculate the operation time of each block in the blockchain network.

Among them, taking the Bitcoin blockchain network as an example, the Bitcoin blockchain creates a block in about 10 minutes and broadcasts it to all nodes in the entire network. However, due to the limited computing power of the Bitcoin blockchain network Fluctuations, the creation time of new blocks will also fluctuate, for example, 10 minutes and 30 seconds, 9 minutes and 30 seconds.

Wherein, the calculation time may be the establishment time of the latest block, or the average value of the establishment time of multiple blocks in the latest time period.

Step S7: According to the operation time and the unit computing power cost, the unit attack cost is obtained.

For example, if the blockchain network includes 100 total computing power, the attacker initiates a double-spend attack, at least controlling more than 50% of the computing power in the blockchain network, such as 51 computing power, the trader initiates a After the transaction, the trader sends a real transaction ticket to the entire blockchain network, and the attacker generates a fake transaction ticket, and uses the principle of "minority obeys the majority" in the consensus mechanism to replace the real transaction ticket with the fake transaction ticket and write In the block of the main blockchain, the real transaction order will be deleted by other target service nodes.

The unit attack cost required for this double-spending attack is P0=p1*51*p2, p1 is the time required for each successful transaction to be confirmed successfully, that is, the time required for each new block to be established, and p2 is the unit computing power the cost of.

In another embodiment, the specific steps of the unit attack cost include: obtaining the maximum computing power value of a single blockchain node in the corresponding blockchain network according to the virtual currency type; calculating the unit of the blockchain network computing power cost; calculating the computing time of each block in the blockchain network; obtaining the unit attack cost according to the maximum computing power value, the unit computing power cost and the computing time.

Specifically, obtain the maximum computing power value of a single blockchain node in the corresponding blockchain network, the unit computing power cost and the computing time, then the blockchain node with the maximum computing power value has the right to obtain the area The maximum probability of accounting rights in the block chain network, the unit attack cost of the attacker is not less than the cost of the node with the maximum computing power value, that is, the unit attack cost is not less than the maximum computing power value multiplied by the unit computing power cost and calculation time.

Step S8: Adjust the number of initial confirmations so that the total attack cost is greater than the transaction value.

The total attack cost is equal to the multiplication of the initial confirmation times by the unit attack cost.

The confirmation indicates that the transaction is recorded and confirmed by the blockchain network. If the number of confirmations is N, when the transaction occurs, the block recording the transaction will be confirmed for the first time, and will be confirmed on the chain after the block. N-1 confirmations are performed for each block of . All these confirmations and transactions are time-stamped on the blockchain, making them irreversible and immutable. If the number of initial confirmations is reached, it can be judged that the transaction is successful.

Adjust the number of initial confirmations based on the unit attack cost and transaction value, so that the total attack cost is greater than the transaction value. The total cost of the double-spending attack is P, where P=P0*N and P>M, where N is the number of confirmations, and M is the transaction value.

In another embodiment, after step S8, a step is also included: if the computing power value of at least one trusted blockchain node in the blockchain network is greater than the computing power value of other blockchain nodes, then adjusting the number of initial confirmations is Basic number of confirmations.

Among them, the number of basic confirmations is the minimum number of confirmations for transaction completion. For example, if at least six confirmations required by the blockchain network or the exchange are completed as one transaction, then the number of basic confirmations is 6 times, and the computing power to ensure safe transactions is trustworthy Blockchain nodes have more than 50% computing power. The trusted blockchain node can be the blockchain node of the trader itself, or a blockchain node trusted by the trader.

In another embodiment, it also includes the step of periodically obtaining the currency price, the total computing power value, the unit computing power cost, the computing time and the maximum value of a single blockchain node in the blockchain network. computing power value; if one of the currency price, the total computing power value, the unit computing power cost, the computing time or the maximum computing power value of a single blockchain node in the blockchain network or more changes, the initial number of confirmations will be adjusted accordingly.

Due to the relatively long trading time of blockchain virtual currency, there are many factors that affect the transaction value during this trading time period, such as skyrocketing virtual currency prices, fluctuations in mining machine rent, electricity bill adjustments, and surges in total computing power, etc., which need to be adjusted based on factors Calculate to obtain the transaction value or unit attack cost, and adjust the number of initial confirmations according to the transaction value or unit attack cost, so that the total attack cost is greater than the transaction value. Further, the number of initial confirmations is not less than the number of basic confirmations.

Step S9: Submit transaction information to the blockchain network.

Specifically, the transaction information is broadcast to the blockchain network, so that a new block records the transaction information.

Step S10: Obtain the confirmation completion times.

Specifically, obtain the newly created block information of the blockchain network after the broadcast information is released, and then obtain the corresponding confirmation completion times.

In an embodiment, step S10 specifically includes the following steps: acquiring a query time period according to the operation time; and sequentially acquiring confirmation completion times according to the query time period.

Specifically, the Bitcoin blockchain creates a block in 10 minutes, then the first confirmation can be queried in the first 10 minutes, and the second confirmation can be queried in the second 10 minutes, and the query is based on the order of the time period to reduce system updates Time, reduce waiting time, save server computing resources, and reduce costs.

Further, the method further includes the steps of: updating the transaction progress according to the confirmed completion times; and displaying the transaction progress in real time.

For example, the transaction progress is calculated by the completed number of confirmations. For example, if the number of confirmations is 5 and the number of completed confirmations is 1, then the transaction progress is 20%.

The transaction progress is displayed in real time through the display unit.

Step S11: Judging whether the number of confirmation completions has reached the initial number of confirmations.

Specifically, it is judged whether the number of newly added blocks in the blockchain network is equal to the number of initial confirmation times.

If yes, go to step S12; if no, go to step S13.

Step S12: It is determined that the transaction is completed.

Further, step S12 also includes the step of: checking the transaction information, and judging whether the transaction is normal: if it is normal, prompting that the transaction is completed; if not, sending an alarm indication.

Step S13: Determine whether there is error information in the transaction process.

In one embodiment, malicious nodes in the blockchain network use accounting rights to modify the transaction content in the block, for example, in the transaction content, "A remits money to B" is changed to "A remits money to C".

In another embodiment, the malicious node in the blockchain network acts as a transaction node and broadcasts two transactions to the network, and one transaction is sent to itself (in order to improve the attack success rate, this transaction adds enough handling fee ), a transaction is issued to a buyer or seller. Since the transaction sent to itself contains a higher handling fee, the probability of being packaged into a block by miners is relatively high.

If not, go to step S11.

If yes, execute step S14: terminate the transaction.

For example, if the online transaction in the blockchain network fails, the offline transaction or the transaction associated with the virtual currency will be terminated. For example, if the virtual currency is not received, the transfer to the trader will be stopped.

Step S15: sending out warning information.

Send alarm information in the form of sound and light, voice, human-machine interface, etc., to notify the relevant person in charge to deal with the abnormal situation.

The above-mentioned method and device for preventing double-spending attacks adjusts the number of confirmations according to the transaction value and the total attack cost, so that the total attack cost is greater than the transaction value, thereby preventing the occurrence of double-spend attacks, ensuring the security of large-amount transactions, and reducing small-amount transactions. The number of transaction confirmations to reduce the transaction time of small transactions, thereby increasing the convenience of small transactions.

Further, the above-mentioned method and device for preventing double-spend attacks use real-time display or voice broadcast of the transaction progress to enable traders to know the transaction status in real time, and detect whether there is any wrong information in the transaction information by detecting the transaction information in real time. And the error information is reminded by the alarm information, so as to realize the timely termination of the transaction and reduce or avoid the transaction loss.

The method provided by the present invention does not need to change the architecture and calculation process of the block chain, and is easy to implement.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, no matter from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, so it is intended to All changes within the meaning and range of equivalents of the elements are included in the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates. Furthermore, it is obvious that the word "comprising" does not exclude other means or steps, and the singular does not exclude the plural.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included within the scope of protection claimed by the present invention.

S1-S15: Steps

Claims (7)

A method for preventing double-spending attacks, the improvement of which is that the method includes: obtaining transaction information to be traded, the transaction information including virtual currency type and transaction quantity; obtaining currency prices according to the virtual currency type; according to the transaction The quantity and the currency price obtain the transaction value; obtain the unit attack cost of the corresponding blockchain network according to the virtual currency type; adjust the number of initial confirmations so that the total attack cost is greater than the transaction value, wherein the total attack cost Equal to the number of times of initial confirmation multiplied by the unit attack cost; and submit the transaction information to the blockchain network; wherein, "obtain the unit attack cost of the corresponding blockchain network according to the virtual currency type" It specifically includes: obtaining the total computing power value of the corresponding blockchain network according to the virtual currency type; calculating the unit computing power cost of the blockchain network; calculating the operation of each block of the blockchain network time; obtain the unit attack cost based on the operation time and the unit computing power cost; or obtain the maximum computing power value of a single blockchain node in the corresponding blockchain network according to the virtual currency type; calculate the area The unit computing power cost of the blockchain network; calculate the computing time of each block of the blockchain network; obtain the unit attack cost according to the maximum computing power value, the unit computing power cost and the computing time ; Wherein, the method also includes the step of periodically obtaining the currency price, the total computing power value, the unit computing power cost, the computing time and the single blockchain node in the blockchain network Maximum computing power value; If one or more of the currency price, the total computing power value, the unit computing power cost, the computing time or the maximum computing power value of a single blockchain node in the blockchain network occurs change, then correspondingly adjust the number of initial confirmations; wherein, the method also includes a step: if the computing power value of at least one trusted blockchain node in the blockchain network is greater than the computing power of other blockchain nodes value, adjust the initial number of confirmations to the basic number of confirmations, and the number of basic confirmations is the minimum number of confirmations for transaction completion. The method for preventing double-spend attacks as described in claim 1, wherein, after submitting the transaction information to the blockchain network, it further includes: obtaining the number of completion confirmations; judging whether the number of completion confirmations reaches the initial number of confirmations: If yes, it is determined that the transaction is completed. The method for preventing double-spending attacks as described in Claim 2, wherein, if the number of completion confirmations does not reach the number of initial confirmations, it is judged whether there is error information in the transaction process: if yes, the transaction is terminated and an alarm message is issued . The method for preventing double-spending attacks as described in Claim 2, wherein "obtaining the number of completed confirmations" specifically includes: obtaining the query time period according to the operation time; and sequentially obtaining the number of confirmation completions according to the query time period. The method for preventing double-spending attacks as described in Claim 4, wherein the method further includes the steps of: updating the transaction progress according to the number of confirmed completions; and displaying the transaction progress in real time. A device for preventing double-spending attacks, which is improved in that it includes: a memory, on which several computer programs are stored; a processor, which is used to execute the computer programs stored in the memory to implement The steps of the method for preventing double-spending attacks described in any one of items 1 to 5. A computer-readable storage medium, the improvement of which is that a computer program is stored thereon, and when the computer program is executed by a processor, the method for preventing double-spending attacks as described in any one of claims 1 to 5 is implemented.

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