CN111639124B - Secure time synchronization method, system, storage medium, program, smart device - Google Patents

Abstract

The invention belongs to the technical field of information processing of the Internet of Things, discloses a safe time synchronization method, system, storage medium, program, and intelligent equipment, and uses decentralized blockchain technology to ensure the authenticity of information in distributed ledgers; The consensus mechanism based on the proof of stability ensures that the system can efficiently and safely elect the best and most stable representative node in the entire network; the terminal device only needs to visit the directly connected time node to obtain the connection of the current representative node, and use the existing The NTP protocol can complete the time synchronization work, which is very simple and convenient. The authorization center exists as an identity authentication center, that is, if a node needs to join the blockchain system, the authorization center needs to perform security authentication on the identity information submitted by it, and only nodes that pass the verification of the authorization center can join the blockchain system as a time node. Alliance; guarantees the credibility of the time nodes in the system, can remove malicious nodes in time, and ensures the stability of the system.

Description

Secure time synchronization method, system, storage medium, program, smart device

technical field

The invention belongs to the technical field of Internet of Things information processing, and in particular relates to a secure time synchronization method, system, storage medium, program, and intelligent device.

Background technique

At present, with the rapid development of smart devices and high-speed networks, the concept of the Internet of Things (IoT) developed on the basis of resource-constrained low-power lossy networks (LLNs) has been accepted and welcomed by all walks of life. Smart devices can complete various tasks after being connected to the Internet of Things, and many of these operations (such as smart home management and surgical monitoring) need to meet high reliability and real-time transmission. If there is a problem with clock synchronization, it will affect daily life at least, such as timing cooking and cleaning the room, which will bring many troubles to people, and seriously affect people's life and property safety, such as timing battery charging, real-time tracking of cars, etc. The current time synchronization schemes mainly include: tree-based time synchronization protocols, graph topology clock time synchronization protocols, and clock synchronization schemes based on Byzantine Fault Tolerance (BFT). In the tree-based time synchronization protocol, the time source exists as the root node of the tree, and the time is passed down from the root node layer by layer to achieve the purpose of time synchronization. However, a significant problem in this method is that when a certain When a node makes an error, the error will be passed on, resulting in an exponential increase in the number of wrong nodes, that is, insufficient robustness. The graph topology clock synchronization protocol has better robustness and scalability by connecting each node to each other and transferring time data between adjacent nodes, but it has not yet solved the security problem. The BFT-based clock synchronization scheme mainly focuses on the stability of clock synchronization in distributed systems, and is not suitable for IoT systems. The computing power of most devices in the Internet of Things is limited, and the complete application of the BFT protocol will reduce the efficiency of the entire system.

Through the above analysis, the problems and defects of the existing technology are: each node in the Internet of Things has the requirement of synchronizing time, but because the Internet of Things system itself is an open system, the nodes in the system are unstable and very vulnerable to attacks, affecting The system's clocks are securely synchronized. Existing distributed system clock synchronization solutions cannot adapt to the Internet of Things system, and cannot use the limited device performance in the Internet of Things to complete clock synchronization more efficiently and safely.

The difficulty in solving the above problems and defects is: to prevent unstable nodes or attacked malicious nodes from affecting the time synchronization in the system, and at the same time to complete efficient, safe and stable clock synchronization tasks under the premise of limited performance of IoT infrastructure equipment , which is the main difficulty in existing IoT clock synchronization methods.

The significance of solving the above problems and defects is to improve the stability and security of clock synchronization in the Internet of Things scenario, and to be able to detect problem nodes in time and control the scope of influence. Under the premise of limited performance of IoT basic equipment, a low-consumption, safer and more efficient clock synchronization scheme is proposed, the original stability consensus scheme is improved, and the complexity of consensus communication is reduced under the premise of ensuring safety. An order of magnitude greatly reduces the resource constraints on the synchronization time nodes in the system and reduces the network communication overhead.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a secure time synchronization method, system, storage medium, program, and intelligent device.

The present invention is achieved in this way, a safe time synchronization method, the safe time synchronization method comprising:

In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work;

In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus;

In the third step, the time node sends a consensus start request in the Negotiation state;

In the fourth step, the time node responds to the consensus start request in the WaitingACK state;

The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock;

In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time;

The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus;

In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK.

Further, the secure time synchronization method also includes:

(1)Running

1) In this state, the representative node is responsible for time service, and other nodes are responsible for routing and addressing operations. The synchronization device obtains the representative node connection from the nearest time node, and uses the NTP protocol to synchronize time with the representative node;

2) Each node will update the node information in the network at this time;

3) Each node processes a new node to join the network. The new node first verifies its identity to the authorization center, obtains a network access license and a security certificate, and then sends a network access request to a node in the running state in the network to join the network;

4) Each node synchronizes the block information between each node, etc. At this time, if it receives a consensus message, it will automatically ignore it;

(2) Waiting Negotiation

1) When the time node enters the time period (tp, tc), its state will be transformed into WaitingNegotiation state; the start time point of each consensus cycle is tp, after time P1 reaches time point tc, and then after time P2 reaches time point te;

2) In this state, the node will prepare some resources needed for consensus, such as the update of the total number of nodes, and the test of the connection quality with other nodes;

3) If the node reaches the tc state at this time and does not receive consensus messages from other nodes during this period, it will transfer to the Negotiation state and broadcast a consensus request to all nodes in the network;

4) If a consensus start request is received in this state, it means that other nodes have entered the tc time point, so the node will broadcast ACK to indicate that it agrees to start this round of consensus, and then transfer to the WaitingACK state;

5) If the latest Block is received in this state and the verification is successful, it means that this round of consensus has ended and it will enter the Running state;

(3)Negotiation

1) When the time node enters the time point tc, it enters this state and broadcasts a consensus start request, and then transfers to the WaitingACK state;

2) However, if the latest Block is received before entering the next state, it will directly enter the Running state to end the current round of consensus;

(4)WaitingACK

1) After receiving and verifying the consensus start request, the node will enter this state to broadcast ACK and wait to receive ACK from other nodes;

2) Each node will confirm that it will reply ACK after receiving the start consensus request from the other party, while in other states, the node will consider the received ACK to be invalid and discard it;

3) If the node does not broadcast ACK but only receives ACK;

4) If the number of ACKs received reaches the threshold, it will enter the WritingVBlock state;

5) If the latest VBlock is received, it means that the competition of the representative node has officially started, and it will directly enter the WaitingVACK state;

6) If the latest Block is received in this state, it means that the consensus is over and it will directly transfer to the Running state;

(5)WritingVBlock

1) After entering this state, the node will obtain and lock the virtual block, pack the received ACK and other information into a virtual block, and broadcast it to other nodes, then it will enter the WaitingVACK state;

2) However, if the latest VBlock of other nodes is received before broadcasting the virtual block, the packaging and sending of its own virtual block will be abandoned, and the status will be transferred to WaitingBlock;

3) If the latest Block is received in this state, the current consensus operation is abandoned and directly enters the Running state;

(6) Waiting VACK

1) In this state, the node will send a VACK response to the nodes in the stability index list, waiting to receive VACK from other nodes;

2) When the received VACK reaches the threshold, enter the WritingBlock state;

3) If the latest Block has been received before, end the current consensus operation and directly enter the Running state;

(7)Writing Block

1) In this state, the node will package the received VACK and its own signature information into a new block Block and broadcast it to the entire blockchain network. When the block is received by other nodes, this node is selected by consensus On behalf of the node, enter the Running state to end the current round of consensus;

2) However, if the latest legal block from other nodes is received before the latest packaged block is sent, then there is no need to package your own block, stop the consensus-related operations, and directly enter the Running state;

(8) Waiting Block

1) In this state, the node will also respond to other nodes VACK;

2) After receiving the latest Block and performing follow-up operations such as verification, it will enter the Running state to complete this round of consensus.

Further, the secure time synchronization method also includes:

Step 1, the authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network;

Step 2, representative node election based on stability proof;

Step 3, publish new blocks on behalf of the node;

Step 4, the time node updates the blockchain;

Step 5, obtain the standard time on behalf of the node;

Step 6: Synchronize device to synchronize time.

Further, said step 1 authorizes the center to authenticate the identity, issue, revoke, and verify the identity, and the node network includes:

1) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy;

2) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of the time node to the certificate revocation list and provide it to the nodes in the network for reference;

3) Verification: When the synchronization device connects to the time node for the first time or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the node at this time is confirmed through the public key in the certificate;

4) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it will broadcast it to all other nodes on the chain so that it can The identity is known by the network. After the connection is successful, the new nodes that join the network will obtain the latest virtual chain data and time chain data from the network, and after verifying and synchronizing the chain information, they can synchronize their own clock information;

The second step, the election of representative nodes based on proof of stability includes:

1) The time node that first enters the _tc time point in the cycle view in the network is ready to start the consensus of this cycle view. It first calculates the total number N of stable nodes that can be connected to it in the current network, and sends its own consensus start request message to the node ;

2) After receiving the node consensus start request message, other nodes first check their own running status. If they are in the (tp, tc) time period in the cycle view, that is, waiting for the consensus start state, they will verify the consensus start request node Whether it is a node in the network, if it is a node in the network, verify its signature identity, if it passes the signature identity verification, query the stability of the node that sent the consensus start request, and reply with its own signature in order from high to low ACK message, no reply message will be given to nodes that are in the bottom 10% of the stability list for more than 5 cycles;

3) After receiving the ACK message, the node that initiates the consensus request first judges its own running status, whether it is waiting for the ACK response stage, if it is in this stage, then verifies the signature identity of the ACK message, if the ACK message passes the signature authentication , are collected and counted. If the node that initiates the consensus request receives legal ACK messages that exceed 2/3 of the total number of network nodes, it will package the ACK messages into VBlocks and broadcast them to other nodes;

4) After receiving the VBlock, other nodes verify its correctness and legitimacy. If it passes the verification, it will write the VBlock into the virtual chain, and send a VACK message with its own signature to the time node that sent the VBlock;

5) The node sending the VBlock verifies the legitimacy and correctness of the VACK after receiving the VACK message. If it passes, it will be collected and counted. If the node receives a number of legal VACK messages exceeding 2/3 of the total number of network nodes, it will be elected as this The representative node of the periodic view consensus;

The step three represents that the node publishes a new block including:

1) The representative node packs the legal VACK messages obtained by more than 2/3 of the total number of network nodes into the new block newBlock;

2) The representative node broadcasts the packaged new block newBlock to the entire network nodes;

The step 4 time node update block chain includes:

1) All time nodes verify the legitimacy and correctness of the newBlock and its contents after receiving the new block newBlock sent by the representative node of the current cycle view consensus;

2) If the newBlock passes the verification, it will be written into the time chain of this node, and the current round of representative election is completed;

The step five represents that the node obtains the standard time including:

1) The representative node sends a time synchronization request to the time source, and the time source verifies the identity of the representative node;

2) If the time source verifies that the identity of the representative node is correct, then use the NTP protocol to output the standard time to the representative node;

3) The representative node obtains the standard time from the time source through the NTP protocol;

The step 6 synchronizing device synchronization time includes:

1) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node;

2) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in the current cycle view to the synchronization device;

3) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol.

Further, the secure time synchronization method also includes:

Step 1, the authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network;

Step 2, the time node sends its own stability table to the group management node;

Step 3, the group management node broadcasts the new block;

Step 4, the time node updates the blockchain and calculates the current round representative node;

Step 5, obtain the standard time on behalf of the node;

Step 6: Synchronize device to synchronize time.

Further, said step 1 authorizes the center to authenticate the identity, issue, revoke, and verify the identity, and the node network includes:

1) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy;

2) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of the time node to the certificate revocation list and provide it to the nodes in the network for reference;

3) Verification: When the synchronization device connects to the time node for the first time or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the node at this time is confirmed through the public key in the certificate;

4) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it broadcasts it to all other nodes on the chain to make its identity Known by the network; after the connection is successful, the new node that joins the network will obtain the latest time chain data from the network, and after verifying and synchronizing the chain information, it can synchronize its own clock information;

In the step 2, the time node sends its own stability table to the group management node including:

1) When the time node enters the t _c time point of each cycle, it is ready to start the consensus of this cycle. It first calculates the degree of stability between each node in the current network and the node, and obtains the stability table of the node;

2) Pack the stability table, the cycle number of this round, and your own node ID into a consensus message, sign it with your own private key, and send the packaged and signed consensus message to the group management node;

The steps of three groups of management nodes broadcasting new blocks include: the group management nodes collect the consensus messages of all nodes in the network and pack all the messages into the block body of the new block, index this block, and the Hash of the previous block value, the current consensus cycle number No, the current timestamp TimeStamp and the Hash value of this block are filled in the block header, and the new block is broadcast to the network.

In the step 4, the time node updates the blockchain, and the calculation of the representative node of this round includes: after the time node receives the new block, it verifies whether the block header is legal, and then takes out the consensus message in the block body to verify whether the message signature and message content are legal , according to the stability table of each node in the legal message content, the node with the highest comprehensive stability in the whole network is summarized, and this node is elected as the representative node elected by this round of consensus;

The step five represents that the node obtains the standard time including:

1) The time node calculates through the new block that it is elected as the representative node elected by this round of consensus;

2) The representative node sends the new block as its own proof of election to the time source, and after passing the verification of the time source, it will synchronize the precise time with the time source and become the timing node of this round;

In step six, the synchronizing device obtains time synchronization from the representative node including:

1) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node;

2) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in this period to the synchronization device;

3) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol.

Another object of the present invention is to provide a computer device, the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following step:

In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work;

In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus;

In the third step, the time node sends a consensus start request in the Negotiation state;

In the fourth step, the time node responds to the consensus start request in the WaitingACK state;

The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock;

In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time;

The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus;

In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK.

Another object of the present invention is to provide a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor performs the following steps:

In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work;

In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus;

In the third step, the time node sends a consensus start request in the Negotiation state;

In the fourth step, the time node responds to the consensus start request in the WaitingACK state;

The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock;

In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time;

The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus;

In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK.

Another object of the present invention is to provide a secure time synchronization system for running the secure time synchronization method, the secure time synchronization system comprising:

The network and synchronous block information adding module are used to realize the time node networking in the Running state, update node information, process new nodes to join the network, and synchronize block information;

Consensus start module, which is used for time nodes to process node connection information updates and connection quality test updates in the WaitingNegotiation state, and prepare to start consensus;

The consensus request sending module is used to realize the time node sending the consensus start request in the Negotiation state;

The consensus request response module is used to realize that the time node responds to the consensus start request in the WaitingACK state;

The state adjustment module is used to collect a sufficient number of response time nodes to enter the WritingVBlock state and broadcast VBlock;

The state collection module is used to realize that the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs sent by other nodes at the same time;

This round of consensus module is used to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus; Nodes in the WaitingBlock state will end the current round of consensus and enter the Running state if they receive the correct Block while responding to VACK.

Another object of the present invention is to provide a smart device equipped with the secure time synchronization system.

Combining all the above-mentioned technical solutions, the advantages and positive effects of the present invention are as follows: the present invention is based on the blockchain data structure and synchronization method to achieve safe and efficient synchronization of time, and utilizes the consensus method based on stability proof to Resist attacks from malicious nodes and prevent unstable nodes from affecting time synchronization. The blockchain is a time-series chain data structure, that is to say, the addition and confirmation of blocks is based on time order. On the other hand, the consensus mechanism based on the proof of stability ensures that the elected stable nodes are recognized by most nodes in the system, and malicious nodes or unstable nodes cannot synchronize the wrong time within the system.

The decentralized blockchain technology used in the present invention ensures the authenticity of the information in the distributed ledger. The hash value on the ledger ensures the integrity and immutability of the election results. If the time node is attacked, if the attacker tampers with the local ledger records to affect the terminal equipment managed by the node, the hash value recorded in the ledger will change, so that the attack launched by the attacker can be identified immediately; The verification feature ensures that any user can freely view the plaintext information of the ledger. If the content of the ledger is damaged, the latest correct distributed ledger can be obtained from the network. Therefore, the present invention can discover the attacked node in time and restore correct data information immediately.

The consensus mechanism based on the proof of stability of the present invention ensures that the representative node with the best and most stable performance in the entire network can be efficiently and safely elected in the system. Each time node in the network maintains the stability between each node device in the network and itself. When the consensus starts, all nodes summarize their respective stability tables, and finally select nodes with higher network performance and high stability as a representative node. Even if malicious nodes do not vote for highly stable nodes according to the consensus rules, as long as malicious nodes and inoperable nodes do not exceed 1/3 of the entire network nodes, they cannot affect the final election results. Therefore, the present invention can effectively resist the attack of malicious nodes on the system, utilize the limited performance of the Internet of Things equipment to efficiently complete the network consensus to select the best quality and most stable representative nodes, and at the same time, because the group management nodes directly complete the summary of the stability table and Electing representative nodes greatly reduces the communication overhead required for consensus in the network.

The terminal device of the present invention only needs to visit the directly connected time node to obtain the connection of the current representative node, and can complete the time synchronization work by using the existing NTP protocol, which is very simple and convenient. The authorization center exists as an identity authentication center, that is, if a node needs to join the blockchain system, the authorization center needs to perform security authentication on the identity information submitted by it, and only nodes that pass the verification of the authorization center can join the blockchain system as a time node. alliance. This ensures the credibility of the time nodes in the system, and at the same time removes malicious nodes in time to ensure the stability of the system.

The design and description of the present invention are based on a finite state machine, which not only makes the system running sequence clearer and more intuitive, but also includes the processing flow of all situations of each node and state, defines the boundary of the system operation, and enhances the stability of the system.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required in the embodiments of the present application. Obviously, the accompanying drawings described below are only some embodiments of the present application. Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is a flowchart of a secure time synchronization method provided by an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a secure time synchronization system provided by an embodiment of the present invention;

In the figure: 1. Network, synchronization block information adding module; 2. Consensus start module; 3. Consensus request sending module; 4. Consensus request response module; 5. Status adjustment module; 6. Status collection module; 7. Current round consensus module.

Fig. 3 is an implementation flow chart of Embodiment 1 provided by the embodiment of the present invention.

Fig. 4 is a system model diagram of Embodiment 1 provided by the embodiment of the present invention.

Fig. 5 is a system flowchart of Embodiment 1 provided by the embodiment of the present invention.

Fig. 6 is a structure diagram of the blockchain ledger in Embodiment 1 provided by the embodiment of the present invention.

FIG. 7 is a scheme architecture diagram of Embodiment 2 provided by the embodiment of the present invention.

Fig. 8 is a flow chart of the solution of Embodiment 2 provided by the embodiment of the present invention.

Fig. 9 is the block ledger structure of the scheme of Embodiment 2 provided by the embodiment of the present invention.

FIG. 10 is a structural diagram of the solution of Embodiment 3 provided by the embodiment of the present invention.

Fig. 11 is a flow chart of the method of the solution of Embodiment 3 provided by the embodiment of the present invention.

Fig. 12 is a block data structure diagram of the solution of Embodiment 3 provided by the embodiment of the present invention.

Fig. 13 is a schematic diagram of Docker provided by the embodiment of the present invention.

Figure 14 is a diagram of the experimental results of the consensus communication complexity provided by the embodiment of the present invention

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Aiming at the problems existing in the prior art, the present invention provides a secure time synchronization method, system, storage medium, program, and intelligent device. The present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the secure time synchronization method provided by the present invention includes the following steps:

S101: The time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work.

S102: The time node processes node connection information update and connection quality test update in the WaitingNegotiation state, and is ready to start consensus.

S103: The time node sends a consensus start request in the Negotiation state.

S104: The time node responds to the consensus start request in the WaitingACK state.

S105: The time node that collects a sufficient number of responses enters the WritingVBlock state and broadcasts the VBlock.

S106: The node enters the WaitingVACK state and sends VACKs to the nodes in the stability index list, and collects VACKs sent by other nodes at the same time.

S107: Nodes that collect a sufficient number of VACKs enter the WritingBlock state to package VACKs and sign, generate Blocks and broadcast them. After other nodes receive the Blocks, this node becomes the representative node of this round, and enters the Running state immediately after the current round of consensus is completed.

S108: The node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK.

As shown in Figure 2, the secure time synchronization system provided by the present invention includes:

Adding module 1 for network and synchronous block information is used to implement time node networking in the Running state, update node information, process new nodes to join the network, and synchronize block information.

Consensus start module 2 is used to process node connection information updates and connection quality test updates when nodes are in the WaitingNegotiation state, and is ready to start consensus.

The consensus request sending module 3 is used to realize that the time node sends a consensus start request in the Negotiation state.

The consensus request response module 4 is used to realize that the time node responds to the consensus start request in the WaitingACK state.

The state adjustment module 5 is used to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock.

The state collection module 6 is used to realize that the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs sent by other nodes at the same time.

This round of consensus module 7 is used to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node will become the representative node of this round. After the end of this round of consensus, it will enter the Running state ; If the node in the WaitingBlock state responds to VACK and receives the correct Block, it will end the current round of consensus and enter the Running state

The technical scheme of the present invention will be further described below in conjunction with the accompanying drawings.

Example 1:

As shown in Figure 3, the main implementation steps of the present invention are as follows:

Step 1: Running

Step 2: Waiting Negotiation

Step 3: Negotiation

Step 4: WaitingACK

Step 5: WritingVBlock

Step 6: WaitingVACK

Step 7: Writing Block

Step 8: Waiting Block

As shown in Figure 5, the specific steps of the present invention are further described as follows:

(1)Running

1a) In this state, the representative node is responsible for time service, and other nodes are responsible for routing and addressing operations. The synchronization device obtains the representative node connection from the nearest time node, and uses the NTP protocol to synchronize time with the representative node.

1b) Each node will update the node information in the network at this time.

1c) Each node handles new nodes joining the network. The new node first verifies its identity to the authorization center, obtains the network access license and security certificate, and then sends a network access request to the node in the running state in the network to join the network.

1d) Each node synchronizes the block information between each node, etc. If it receives a consensus message at this time, it will automatically ignore it.

(2) Waiting Negotiation

2a) When the time node enters the time period (tp, tc), its state will be transformed into WaitingNegotiation state. (Assume that each consensus cycle starts at tp, reaches time point tc after time P1, and reaches time point te after time P2)

2b) In this state, the node will prepare some resources needed for consensus, such as updating the total number of nodes, testing the connection quality with other nodes, etc.

2c) If the node reaches the tc state at this time and does not receive consensus messages from other nodes during this period, it will transfer to the Negotiation state and broadcast a start consensus request to all nodes in the network.

2d) If a consensus start request is received in this state, it means that other nodes have entered the tc time point, so the node will broadcast ACK to agree to start this round of consensus, and then transfer to the WaitingACK state.

2e) If the latest Block is received in this state and the verification is successful, it means that this round of consensus has ended and it will enter the Running state.

(3)Negotiation

3a) When the time node enters the time point tc, it will enter this state and broadcast the consensus start request, and then transfer to the WaitingACK state.

3b) However, if the latest Block is received before entering the next state, it will directly enter the Running state to end the current round of consensus.

(4)WaitingACK

4a) After receiving and verifying the consensus start request, the node will enter this state to broadcast ACK and wait to receive ACK from other nodes.

4b) Each node will confirm that it will reply ACK after receiving the start consensus request from the other party, while in other states, the node will consider the received ACK to be invalid and discard it.

4c) If a node does not broadcast ACK but only receives ACK, because of the existence of the stability index table, its stability index in other nodes must be greatly reduced, resulting in a disadvantage in subsequent competition.

4d) If the number of ACKs received reaches the threshold, it will enter the WritingVBlock state.

4e) If the latest VBlock is received, it means that the competition for the representative node has officially started, and it will directly enter the WaitingVACK state.

4f) If the latest Block is received in this state, it means that the consensus is over and it will go directly to the Running state.

(5)WritingVBlock

5a) After entering this state, the node will obtain and lock the virtual block, then pack the received ACK and other information into a virtual block, broadcast it to other nodes, and then enter the WaitingVACK state.

5b) However, if the latest VBlock of other nodes is received before broadcasting the virtual block, the packaging and sending of its own virtual block is abandoned, and the status is transferred to WaitingBlock.

5c) If the latest Block is received in this state, the current consensus operation is abandoned and directly enters the Running state.

(6) Waiting VACK

6a) In this state, the node will send a VACK response to the nodes in the stability index list, and then wait to receive VACK from other nodes.

6b) When the received VACK reaches the threshold, it will enter the WritingBlock state.

6c) If the latest Block has been received before, end the current consensus operation and enter the Running state directly.

(7)Writing Block

7a) In this state, the node will package the received VACK and its own signature into a new block Block and broadcast it to the entire blockchain network. When the block is received by other nodes, the node is selected by consensus. The representative node that has been selected can enter the Running state to end the current round of consensus.

7b) However, if the latest legal block from other nodes is received before the latest packaged block is sent, then there is no need to package your own block, so stop the consensus-related operations and directly enter the Running state.

(8) Waiting Block

8a) In this state, the node will also respond to other nodes with VACK, but since the competition for VBlock has already failed, no new Block will be packaged, so as to reduce the amount of messages sent in the network and the resource consumption of nodes.

8b) After receiving the latest Block and performing follow-up operations such as verification, it will enter the Running state to complete this round of consensus.

Example 2:

The secure time synchronization method provided by the present invention comprises the following steps:

Step 1: The authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network;

Step 2: Representative node election based on proof of stability;

Step 3: Publish a new block on behalf of the node;

Step 4: The time node updates the blockchain;

Step 5: Obtain the standard time on behalf of the node;

Step 6: Synchronize device to synchronize time.

Concrete steps of the present invention are further described as follows:

(1) The authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network

1a) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy.

1b) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of this time node to the certificate revocation list and provide it to the nodes in the network for reference.

1c) Verification: When the synchronization device first connects to the time node or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the time node can be confirmed through the public key in the certificate.

1d) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it will broadcast it to all other nodes on the chain to make it The identity is known by the network. After the connection is successful, the new node that joins the network will obtain the latest virtual chain data and time chain data from the network. After verifying and synchronizing the chain information, it can synchronize its own clock information.

(2) Representative node election based on proof of stability

2a) The time node that first enters the _tc time point in the cycle view in the network is ready to start the consensus of this cycle view. It first calculates the total number N of stable nodes that can be connected to it in the current network, and sends its own consensus start request to these nodes information.

2b) After receiving the node consensus start request message, other nodes first check their own running status. If they are within the time period (t _p , t _c ) in the cycle view, that is, waiting for the consensus start state, they will verify the consensus start request Whether the node is a node in the network, if it is a node in the network, verify its signature identity, if it passes the signature identity verification, query the stability of the node that sent the consensus start request, and then reply with For the ACK message with its own signature, it will not reply to the nodes that are in the bottom 10% of the stability list for more than 5 cycles.

2c) After receiving the ACK message, the node that initiates the consensus request first judges its own running status, whether it is waiting for the ACK response stage, if it is in this stage, then verify the signature identity of the ACK message, if the ACK message passes the signature authentication , are collected and counted. If the node that initiates the consensus request receives legal ACK messages that exceed 2/3 of the total number of network nodes, these ACK messages will be packaged into VBlocks and broadcast to other nodes.

2d) After receiving the VBlock, other nodes verify its correctness and legitimacy. If it passes the verification, it will write the VBlock into the virtual chain, and send a VACK message with its own signature to the time node that sent the VBlock.

2e) The node that sends the VBlock verifies the legitimacy and correctness of the VACK after receiving the VACK message. If it passes, it collects and counts it. If the node receives a legal VACK message that exceeds 2/3 of the total number of network nodes, it is elected as this The representative node of the cycle view consensus.

(3) Release a new block on behalf of the node

3a) The representative node packs the obtained legal VACK messages exceeding the threshold (2/3 of the total number of network nodes) into a new block newBlock.

3b) The representative node broadcasts the packaged new block newBlock to the entire network nodes.

(4) The time node updates the blockchain

4a) All time nodes verify the legitimacy and correctness of the newBlock and its contents after receiving the new block newBlock sent by the representative node of the current cycle view consensus.

4b) If the newBlock passes the verification, it will be written into the time chain of this node, and the current round of representative election is completed.

(5) Obtain the standard time on behalf of the node

5a) The representative node sends a time synchronization request to the time source, and the time source verifies the identity of the representative node.

5b) If the time source verifies that the identity of the representative node is correct, then use the NTP protocol to output the standard time to the representative node.

5c) represents that the node obtains the standard time from the time source through the NTP protocol.

(6) Synchronization device synchronization time

6a) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node.

6b) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in the current cycle view to the synchronization device.

6c) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol.

Example 3:

The secure time synchronization method provided by the present invention comprises the following steps:

Step 1: The authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network;

Step 2: The time node sends its own stability table to the group management node;

Step 3: The group management node broadcasts the new block;

Step 4: The time node updates the blockchain and calculates the representative node for this round;

Step 5: Obtain the standard time on behalf of the node;

Step 6: Synchronize device to synchronize time.

Concrete steps of the present invention are further described as follows:

(1) The authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network

1a) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy.

1b) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of this time node to the certificate revocation list and provide it to the nodes in the network for reference.

1c) Verification: When the synchronization device first connects to the time node or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the time node can be confirmed through the public key in the certificate.

1d) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it will broadcast it to all other nodes on the chain to make it The identity is known by the network. After the connection is successful, the node that newly joins the network will obtain the latest time chain data from the network, and after verifying and synchronizing the chain information, it can synchronize its own clock information.

(2) The time node sends its own stability table to the group management node

2a) When the time node enters the t _c time point of each cycle, it is ready to start the consensus of this cycle. It first calculates the degree of stability between each node in the current network and the node, and obtains the stability table of the node.

2b) Pack the stability table, the current cycle number, and your own node ID into a consensus message, sign it with your own private key, and send the packaged and signed consensus message to the group management node.

(3) Group management nodes broadcast new blocks

3a) The group management node collects the consensus messages of all nodes in the network and packs all the messages into the block body of the new block, indexes the block with Index, the hash value of the previous block, the current consensus cycle number No, and the current time Stamp the TimeStamp and the Hash value of this block into the block header, and broadcast the new block to the network.

(4) The time node updates the blockchain and calculates the current round representative node

4a) After the time node receives the new block, it verifies whether the block header is legal, and then takes out the consensus message in the block body to verify whether the message signature and message content are legal, and summarizes the entire network according to the stability table of each node in the legal message content. The node with the highest comprehensive stability among the nodes will be elected as the representative node elected by this round of consensus.

(5) Obtain the standard time on behalf of the node

5a) The time node calculates through the new block that it is elected as the representative node elected by this round of consensus.

5b) The representative node sends the new block as its own proof of election to the time source, and after passing the verification of the time source, it synchronizes the precise time with the time source and becomes the timing node of this round.

(6) The synchronization device obtains time synchronization from the representative node

6a) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node.

6b) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in this period to the synchronization device.

6c) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol.

In the original scheme, after all nodes in the network have tested their stability with other nodes in the network, each node still needs to maintain connection and communication with all nodes in the entire network during the consensus phase, and the communication complexity is O(n ² ). Because of the introduction of the group management node, in the improved scheme, after the synchronization node has tested the stability with other nodes in the network, each node only needs to maintain a connection with the group management node during the consensus stage, and the entire consensus process only needs to The consensus can be completed by sending two messages back and forth with the group management node, and the overall network communication complexity is reduced to O(n), which greatly reduces the communication overhead and stability of the consensus.

The technical effects of the present invention will be described in detail below in conjunction with experiments.

The main simulation test of the present invention is implemented using the programming language Java, developed and implemented by using the intellij idea integrated development environment, and uses Maven to ensure dependent version control. In order to deploy and run this system, the hardware operating environment of this experiment is:

i5-8500 3.0GHz CPU;

32GB RAM;

1TB hard drive;

The operating system is Ubuntu 14.04 Trusty.

The principle of Docker is shown in Figure 13.

The software operating environment is docker version2.0.0.0. In the actual test process, the minimum number of running nodes is 5, and the maximum number is 25. Docker is a virtualized application container that can use less system resources to provide independent running sandbox environments for different applications, and can better simulate a large number of physical device node scenarios under the Internet of Things. The principle diagram of docker is shown in the figure. Each container does not create a virtual OS kernel independently, but an independent Bins/Libs environment to improve the utilization of resources.

The system is generally divided into 9 modules: timer, state machine, P2P module, API module, Block module, tool set, Peer module, MessageHelper module, NTP module, and the core module is the P2P module.

It can be seen from the figure that the timer of the system drives the state machine to run, and the state machine and the P2P module interact with each other. The state change of the state machine will lead to the change of the P2P operation state, and the operation of P2P will also cause the state transition event of the state machine . The API exposes the interface to the outside, which can be connected with other programs and devices. The Block module manages the blockchain data part. The tool set integrates the basic methods required for system operation, such as encryption, signature and other basic algorithms. The Peer module manages the P2P network The specific implementation part of the connection, MessageHelper is the encapsulation of message transmission and processing methods between nodes, and the NTP module is an independently running module that can provide NTP services, and it can also be called to implement this node and other nodes when needed Or the device performs clock synchronization.

The invention compares the communication complexity test between the improved time security synchronization scheme and the original stability consensus scheme. The present invention judges the communication complexity of the two schemes by changing the number of nodes participating in the consensus and observing the average message flow in each consensus network, as shown in FIG. 14 . The number of nodes ranges from 5 to 25, increasing by 5 nodes each time. It can be seen from Figure 14 that as the number of nodes increases, the consensus traffic of the original stability consensus increases exponentially, which reflects the original stability consensus Communication overhead increases rapidly as the number of participating nodes increases. However, although the consensus traffic of the improved stability consensus of the present invention changes linearly without increasing too much, the relationship between the traffic and participating nodes is stable at 2 times.

It should be noted that the embodiments of the present invention can be realized by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in memory and executed by a suitable instruction execution system such as a microprocessor or specially designed hardware. Those of ordinary skill in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and/or contained in processor control code, for example, on a carrier medium such as a magnetic disk, CD or DVD-ROM, such as a read-only memory Such code is provided on a programmable memory (firmware) or on a data carrier such as an optical or electronic signal carrier. The device and its modules of the present invention may be implemented by hardware circuits such as VLSI or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., It can also be realized by software executed by various types of processors, or by a combination of the above-mentioned hardware circuits and software such as firmware.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope disclosed in the present invention, whoever is within the spirit and principles of the present invention Any modifications, equivalent replacements and improvements made within shall fall within the protection scope of the present invention.

Claims (10)

1. A secure time synchronization method, characterized in that, the secure time synchronization method comprises: In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work; In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus; In the third step, the time node sends a consensus start request in the Negotiation state; In the fourth step, the time node responds to the consensus start request in the WaitingACK state; The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock; In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time; The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus; In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK. 2. The secure time synchronization method according to claim 1, wherein the secure time synchronization method further comprises: (1)Running 1) In this state, the representative node is responsible for time service, and other nodes are responsible for routing and addressing operations. The synchronization device obtains the representative node connection from the nearest time node, and uses the NTP protocol to synchronize time with the representative node; 2) Each node will update the node information in the network at this time; 3) Each node processes a new node to join the network. The new node first verifies its identity to the authorization center, obtains a network access license and a security certificate, and then sends a network access request to a node in the running state in the network to join the network; 4) Each node synchronizes the block information between each node, etc. At this time, if it receives a consensus message, it will automatically ignore it; (2) Waiting Negotiation 1) When the time node enters the time period (t _p , t _c ), its state will transform into WaitingNegotiation state; the start time point of each consensus cycle is t _p , after time P ₁ reaches the time point t _c , and then Time point t _e is reached after time P ₂ ; 2) In this state, the node will prepare some resources needed for consensus, such as the update of the total number of nodes, and the test of the connection quality with other nodes; 3) If the node reaches the _tc state at this time and does not receive consensus messages from other nodes during the period, it will transfer to the Negotiation state and broadcast a consensus request to all nodes in the network; 4) If a consensus start request is received in this state, it means that other nodes have entered the t _c time point, so the node will broadcast ACK to indicate that it agrees to start this round of consensus, and then transfer to the WaitingACK state; 5) If the latest Block is received in this state and the verification is successful, it means that this round of consensus has ended and it will enter the Running state; (3)Negotiation 1) When the time node enters the time point t _c , it enters this state and broadcasts the consensus start request, and then transfers to the WaitingACK state; 2) However, if the latest Block is received before entering the next state, it will directly enter the Running state to end the current round of consensus; (4)WaitingACK 1) After receiving and verifying the consensus start request, the node will enter this state to broadcast ACK and wait to receive ACK from other nodes; 2) Each node will confirm that it will reply ACK after receiving the start consensus request from the other party, while in other states, the node will consider the received ACK to be invalid and discard it; 3) If the node does not broadcast ACK but only receives ACK; 4) If the number of ACKs received reaches the threshold, it will enter the WritingVBlock state; 5) If the latest VBlock is received, it means that the competition of the representative node has officially started, and it will directly enter the WaitingVACK state; 6) If the latest Block is received in this state, it means that the consensus is over and it will directly transfer to the Running state; (5)WritingVBlock 1) After entering this state, the node will obtain and lock the virtual block, pack the received ACK and other information into a virtual block, and broadcast it to other nodes, then it will enter the WaitingVACK state; 2) However, if the latest VBlock of other nodes is received before broadcasting the virtual block, the packaging and sending of its own virtual block will be abandoned, and the status will be transferred to WaitingBlock; 3) If the latest Block is received in this state, the current consensus operation is abandoned and directly enters the Running state; (6) Waiting VACK 1) In this state, the node will send a VACK response to the nodes in the stability index list, waiting to receive VACK from other nodes; 2) When the received VACK reaches the threshold, enter the WritingBlock state; 3) If the latest Block has been received before, end the current consensus operation and directly enter the Running state; (7)Writing Block 1) In this state, the node will package the received VACK and its own signature information into a new block Block and broadcast it to the entire blockchain network. When the block is received by other nodes, this node is selected by consensus On behalf of the node, enter the Running state to end the current round of consensus; 2) However, if the latest legal block from other nodes is received before the latest packaged block is sent, then there is no need to package your own block, stop the consensus-related operations, and directly enter the Running state; (8) Waiting Block 1) In this state, the node will also respond to other nodes VACK; 2) After receiving the latest Block and performing follow-up operations such as verification, it will enter the Running state to complete this round of consensus. 3. The secure time synchronization method according to claim 1, wherein the secure time synchronization method further comprises: Step 1, the authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network; Step 2, representative node election based on stability proof; Step 3, publish new blocks on behalf of the node; Step 4, the time node updates the blockchain; Step 5, obtain the standard time on behalf of the node; Step 6: Synchronize device to synchronize time. 4. The safe time synchronization method according to claim 3, wherein said step 1 authorizes the center to authenticate identity, issue, revoke, and verify identity, and node network access includes: 1) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy; 2) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of the time node to the certificate revocation list and provide it to the nodes in the network for reference; 3) Verification: When the synchronization device connects to the time node for the first time or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the node at this time is confirmed through the public key in the certificate; 4) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it will broadcast it to all other nodes on the chain so that it can The identity is known by the network; after the connection is successful, the newly joined network node will obtain the latest virtual chain data and time chain data from the network, and after verifying and synchronizing the chain information, it can synchronize its own clock information; The second step, the election of representative nodes based on proof of stability includes: 1) The time node that first enters the _tc time point in the cycle view in the network is ready to start the consensus of this cycle view. It first calculates the total number N of stable nodes that can be connected to it in the current network, and sends its own consensus start request message to the node ; 2) After receiving the node consensus start request message, other nodes first check their own running status. If they are within the time period (t _p , t _c ) in the cycle view, that is, waiting for the consensus start state, they will verify the consensus start request Whether the node is a node in the network, if it is a node in the network, verify its signature identity, if it passes the signature identity verification, query the stability of the node that sent the consensus start request, and reply with The self-signed ACK message will not reply to the nodes that are in the bottom 10% of the stability list for more than 5 cycles; 3) After receiving the ACK message, the node that initiates the consensus request first judges its own running status, whether it is waiting for the ACK response stage, if it is in this stage, then verifies the signature identity of the ACK message, if the ACK message passes the signature authentication , then collect and count them; if the node that initiates the consensus request receives legal ACK messages that exceed 2/3 of the total number of network nodes, it will pack the ACK messages into VBlocks and broadcast them to other nodes; 4) After receiving the VBlock, other nodes verify its correctness and legitimacy. If it passes the verification, it will write the VBlock into the virtual chain, and send a VACK message with its own signature to the time node that sent the VBlock; 5) The node sending the VBlock verifies the legitimacy and correctness of the VACK after receiving the VACK message. If it passes, it will be collected and counted. If the node receives a number of legal VACK messages exceeding 2/3 of the total number of network nodes, it will be elected as this The representative node of the periodic view consensus; The step three represents that the node publishes a new block including: 1) The representative node packs the legal VACK messages obtained by more than 2/3 of the total number of network nodes into the new block newBlock; 2) The representative node broadcasts the packaged new block newBlock to the entire network nodes; The step 4 time node update block chain includes: 1) All time nodes verify the legitimacy and correctness of the newBlock and its contents after receiving the new block newBlock sent by the representative node of the current cycle view consensus; 2) If the newBlock passes the verification, it will be written into the time chain of this node, and the current round of representative election is completed; The step five represents that the node obtains the standard time including: 1) The representative node sends a time synchronization request to the time source, and the time source verifies the identity of the representative node; 2) If the time source verifies that the identity of the representative node is correct, then use the NTP protocol to output the standard time to the representative node; 3) The representative node obtains the standard time from the time source through the NTP protocol; The step 6 synchronizing device synchronization time includes: 1) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node; 2) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in the current cycle view to the synchronization device; 3) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol. 5. The secure time synchronization method according to claim 1, wherein the secure time synchronization method further comprises: Step 1, the authorization center authenticates the identity, issues, revokes, and verifies the identity, and the node enters the network; Step 2, the time node sends its own stability table to the group management node; Step 3, the group management node broadcasts the new block; Step 4, the time node updates the blockchain and calculates the current round representative node; Step 5, obtain the standard time on behalf of the node; Step 6: Synchronize device to synchronize time. 6. The secure time synchronization method according to claim 5, wherein said step one authorizes the center to authenticate identity, issue, revoke, and verify identity, and node network access includes: 1) Authentication and distribution: If the time node wants to join the alliance chain system and participate in the consensus, it needs to send its real identity information to the authorization center for authentication. If the authentication passes, the authorization center will record the identity information of the node and issue it to it. A security certificate, the security certificate includes a unique serial number, the public key of the authentication node and the signature of the authorization center, where the serial number represents the real identity of the authentication node, the public key is used to verify the signature to confirm the identity, and the signature of the authorization center is used as the security certificate proof of legitimacy; 2) Revocation: The authorization center maintains a certificate revocation list. If there is a malicious behavior at a certain time node and the network consensus decides to expel it, or the private key of a certain time node is leaked and a certain time node needs to withdraw from the network, the authorization center Add the security certificate number of the time node to the certificate revocation list and provide it to the nodes in the network for reference; 3) Verification: When the synchronization device connects to the time node for the first time or confirms the identity between time nodes, first check the security certificate of the node to be verified, verify the validity of the security certificate, that is, whether the signature of the authorization center is correct, and then check the authorization center Check the certificate revocation list to check whether the security certificate has been revoked. If the security certificate is legal and has not been revoked, the node has passed the identity verification, and the identity of the node at this time is confirmed through the public key in the certificate; 4) Network access: If a time node wants to join the network, it applies to a certain time node in the network to join the network. After the connected time node passes its identity verification, it broadcasts it to all other nodes on the chain to make its identity Known by the network; after the connection is successful, the new node that joins the network will obtain the latest time chain data from the network, and after verifying and synchronizing the chain information, it can synchronize its own clock information; In the step 2, the time node sends its own stability table to the group management node including: 1) When the time node enters the t _c time point of each cycle, it is ready to start the consensus of this cycle. It first calculates the degree of stability between each node in the current network and the node, and obtains the stability table of the node; 2) Pack the stability table, the cycle number of this round, and your own node ID into a consensus message, sign it with your own private key, and send the packaged and signed consensus message to the group management node; The steps of three groups of management nodes broadcasting new blocks include: the group management nodes collect the consensus messages of all nodes in the network and pack all the messages into the block body of the new block, index this block, and the Hash of the previous block value, the current consensus cycle number No, the current timestamp TimeStamp and the Hash value of this block are filled in the block header, and the new block is broadcast to the network; In the step 4, the time node updates the blockchain, and the calculation of the representative node of this round includes: after the time node receives the new block, it verifies whether the block header is legal, and then takes out the consensus message in the block body to verify whether the message signature and message content are legal , according to the stability table of each node in the legal message content, the node with the highest comprehensive stability in the whole network is summarized, and this node is elected as the representative node elected by this round of consensus; The step five represents that the node obtains the standard time including: 1) The time node calculates through the new block that it is elected as the representative node elected by this round of consensus; 2) The representative node sends the new block as its own proof of election to the time source, and after passing the verification of the time source, it will synchronize the precise time with the time source and become the timing node of this round; In step six, the synchronizing device obtains time synchronization from the representative node including: 1) A synchronization device that needs to synchronize time sends a time synchronization request to its connected time node; 2) After receiving the synchronization request sent by the synchronization device, the time node sends the current representative node connection in this period to the synchronization device; 3) The synchronization device applies to the representative node for time synchronization, and the synchronization device obtains the standard time from the representative node through the NTP protocol. 7. A computer device, characterized in that the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor is made to perform the following steps: In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work; In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus; In the third step, the time node sends a consensus start request in the Negotiation state; In the fourth step, the time node responds to the consensus start request in the WaitingACK state; The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock; In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time; The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus; In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK. 8. A computer-readable storage medium, storing a computer program, when the computer program is executed by a processor, the processor is made to perform the following steps: In the first step, the time node forms a network in the Running state, updates node information, processes new nodes to join the network, and synchronizes block information. The representative node is responsible for the timing work, and other nodes are responsible for the routing and addressing work; In the second step, the time node processes node connection information updates and connection quality test updates in the WaitingNegotiation state, and is ready to start consensus; In the third step, the time node sends a consensus start request in the Negotiation state; In the fourth step, the time node responds to the consensus start request in the WaitingACK state; The fifth step is to collect a sufficient number of time nodes to enter the WritingVBlock state and broadcast VBlock; In the sixth step, the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs from other nodes at the same time; The seventh step is to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus; In the eighth step, the node in the WaitingBlock state will end the current round of consensus and enter the Running state if it receives the correct Block while responding to the VACK. 9. A secure time synchronization system running the secure time synchronization method according to any one of claims 1 to 6, wherein the secure time synchronization system comprises: The network and synchronous block information adding module are used to realize the time node networking in the Running state, update node information, process new nodes to join the network, and synchronize block information; Consensus start module, which is used for time nodes to process node connection information updates and connection quality test updates in the WaitingNegotiation state, and prepare to start consensus; The consensus request sending module is used to realize the time node sending the consensus start request in the Negotiation state; The consensus request response module is used to realize that the time node responds to the consensus start request in the WaitingACK state; The state adjustment module is used to collect a sufficient number of response time nodes to enter the WritingVBlock state and broadcast VBlock; The state collection module is used to realize that the node enters the WaitingVACK state and sends VACK to the nodes in the stability index list, and collects VACKs sent by other nodes at the same time; This round of consensus module is used to collect a sufficient number of VACK nodes to enter the WritingBlock state to package VACK and sign, generate a Block and broadcast it. After other nodes receive the Block, this node becomes the representative node of this round, and enters the Running state after the end of this round of consensus; Nodes in the WaitingBlock state will end the current round of consensus and enter the Running state if they receive the correct Block while responding to VACK. 10. An intelligent device, characterized in that the intelligent device is equipped with the secure time synchronization system according to claim 9.

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