WO2023224592A1

WO2023224592A1 - Secure communication protocol for swarms of unmanned aerial vehicles (uavs)

Info

Publication number: WO2023224592A1
Application number: PCT/TR2023/050451
Authority: WO
Inventors: Orhan DAGDEVIREN; Umut Can CABUK; Gokhan DALKILIC
Original assignee: Ege Üni̇versi̇tesi̇; Dokuz Eylul Universitesi Rektorlugu
Priority date: 2022-05-18
Filing date: 2023-05-17
Publication date: 2023-11-23

Abstract

The present invention relates to an unmanned aerial vehicle system comprising at least one master unmanned aerial vehicle (10), at least one subordinate unmanned aerial vehicle (20), an authorization element (A) configured to generate a password that will enable a subordinate unmanned aerial vehicle (20) to connect to a network based on time-variable data, a communication module (H) configured to transmit said password to a subordinate unmanned aerial vehicle (20), a further communication module (H) configured to receive and return the password from said communication module (H), a memory module (M) associated with the subordinate unmanned aerial vehicle (20), in which the password generated by the authorization element (A) will be stored and a processing module (P) configured to compare the data from the subordinate unmanned aerial vehicle (20) with the password generated by the authorization element (A) and generate an authorization or rejection response based on this comparison.

Description

SECURE COMMUNICATION PROTOCOE FOR SWARMS OF UNMANNED AERIAE VEHICLES (UAVs)

Technical Field of the Invention

The present invention relates to a computer-implemented method that ensures the security of wireless communication in unmanned aerial vehicle (UAV) swarms and an unmanned aerial vehicle system operating according to the said method.

State of the Art

Unmanned aerial vehicles (UAVs) are used in many areas, especially in military applications. While single use of unmanned aerial vehicles is possible, swarms, including multiple unmanned aerial vehicles, are often used for complex missions.

It is of great importance that unmanned aerial vehicles working in swarms communicate with each other and are connected to a common network to disclose their missions synchronously with each other.

Although the mission in the aforementioned swarms starts when all swarm members are connected to a common network, one or a plurality of unmanned aerial vehicles may disconnect from the network due to adverse conditions that occur during the mission. In such cases, it is not desirable for the unmanned aerial vehicle or vehicles that are disconnected from the network to continue their mission without reconnecting to the network, and accordingly, while it is desirable to reconnect the relevant unmanned aerial vehicles to the network at the first available moment, it is also necessary to ensure communication security during the reconnection to the network.

In the state-of-the-art, ground station (base station, control center, etc.) structures are needed to ensure security if new unmanned aerial vehicles are added to an existing unmanned aerial vehicle network or later separated for further inclusion. The main disadvantage of the method with a ground station is the high cost of installation of these structures. On the other hand, if there are no suitable land conditions, it is not possible to install the said ground stations. The unmanned aerial vehicles are registered to the network with their identity information and then synchronized based on a certain geometric form in the ground station system, according to US20160293018A1. Here, during the disconnection or connection of an unmanned aerial vehicle, the system maintains the positions of the unmanned aerial vehicles in a way that preserves the geometric form of the fleet. In this system, the above-mentioned ground station continues its disadvantages.

As an alternative to ground stations, pre-shared encryption methods can also be used to protect the networks of unmanned aerial vehicles. The biggest disadvantage of this method is that if the password is stolen, the entire network becomes vulnerable to threats, which can easily lead to attackers infiltrating said network in military networks.

However, dynamic information generated during the swarm mission (such as the average remaining energy level of all devices in the swarm) cannot be stolen beforehand. Updating this information periodically also minimizes the possibility of theft or prediction.

As a result, all the above-mentioned problems have made it necessary to improve in the relevant technical field.

Objects and Brief Description of the Invention

The main object of the present invention is to increase the efficiency of the unmanned aerial vehicle network security protocols and accordingly prevent the infiltration of the network from the outside.

A further object of the present invention is to provide authentication during the reconnecting of the disconnected unmanned aerial vehicle to the network if an unmanned aerial vehicle leaves the communication network due to wind, storm, enemy fire, accident, malfunction, or just for the sake of mission, the division into two groups and similar environmental reasons.

Accordingly, the present invention comprises at least one master unmanned aerial vehicle, at least one subordinate unmanned aerial vehicle, an authorization element configured to generate a password that will enable a subordinate unmanned aerial vehicle to connect to a network based on time-variable data, a communication module configured to transmit said password to a subordinate unmanned aerial vehicle, a further communication module configured to receive and return the password from said communication module, a memory module associated with the subordinate unmanned aerial vehicle, in which the password generated by the authorization element will be stored and a processing module configured to compare the data from the subordinate unmanned aerial vehicle with the password generated by the authorization element and generate an authorization or rejection response based on this comparison.

Thus, dynamic encryption is provided for participation in the network by using contextual information specific to the ongoing operation of the devices in the network or environmental conditions or some information showing the status of the network and the devices in the network. Introducing this type of encryption method eliminates the cost of installation in ground stations and is also much more secure than predetermined encryption methods. The process subject to the invention provides high security with the help of its context awareness feature. Context information is embedded in the message traffic and security algorithm for authentication and authorization purposes. This information is requested from devices that were members of the network before but disconnect later and want to reconnect the network.

In a preferred embodiment of the invention, while all unmanned aerial vehicle devices are connected to the swarm wireless network, the master unmanned aerial vehicle periodically sends some private information that external observers cannot distinguish from other subordinate unmanned aerial vehicles in the network. This information can be computational information such as the center of gravity of the locations of the devices in the network or the completion rate of the mission being performed, or any sensor measurement such as the instantly sensed air temperature. This information is announced to all devices on the network, preferably with a time stamp indicating when it was provided and the inventory of all of them is recorded by the master unmanned aerial vehicle in the digital environment, again with the time stamp Then, during the mission, one or more of the subordinate unmanned aerial vehicles in the network may temporarily or permanently lose wireless communication with the above-mentioned network as a result of an accident or environmental factors. If the devices that are separated from the swarm or have fallen apart from the swarm and therefore disconnected from the wireless network find the opportunity to re-join the swarm in the later stages, in this case, a question message is transmitted by the master unmanned aerial vehicle to these subordinate unmanned aerial vehicles, prompting them to provide valid context information. In response to this request message, subordinate unmanned aerial vehicles that want to reconnect to the network transmit the most recent context information in their memory with the relevant time stamp to the master unmanned aerial vehicle in a wireless environment. If the given context information matches the records of the master unmanned aerial vehicle, the records of the requesting unmanned aerial vehicles to join the swarm are approved and included in the network.

If a plurality of subordinate unmanned aerial vehicles has fallen apart from the swarm but has not lost wireless communication with each other, one of them is appointed as a proxy. When this group of unmanned aerial vehicles wants to reconnect to the swarm, only this proxy unmanned aerial vehicle communicates with the master unmanned aerial vehicle, if the verification is successful, the other client unmanned aerial vehicles are considered to have joined the network automatically and the necessary information is given to them by the master unmanned aerial vehicle.

Description of the Figures of the Invention

The figures and related explanations used to better explain the device developed according to the present invention are as follows.

Figure 1. A schematic view of a system in which all unmanned aerial vehicles are connected to the network.

Figure la. A schematic view showing the situation where some unmanned aerial vehicles are disconnected from the network.

Figure lb. A schematic view showing the situation where unmanned aerial vehicles that are disconnected from the network send a request to reconnect to the network.

Figure 2. A schematic view of the master and subordinate unmanned aerial vehicle.

Figure 3. Diagram showing the process for connecting the master and subordinate unmanned aerial vehicles to the network.

Definitions of Elements/Sections/Parts that Constitute the Invention

In order to better explain the device developed according to the present invention, the parts and components in the figures are numbered, and the equivalent of each number is given below.

10. Master unmanned aerial vehicle 20. Subordinate unmanned aerial vehicle

A. Authorization element

H. Communication module

P. Processing module

S. Sensor

M. Memory module

K. Control module

E. Encryption function

K+. Asymmetric public key

K-. Asymmetric secret key

ID. UAV device identity

CR. Parameter specifying information request

C. Context information

N. Randomly generated number

T. Timestamp

L. Identity information list

Ks. Symmetric session key

MID. Number of the ongoing mission

I. Participation request parameter

||. End-to-end splice operator

Detailed Description of the Invention

The present invention is an authentication and authorization method based on the principle that a group of unmanned aerial vehicles, which operate autonomously or using a team, communicate with each other via wireless communication technologies. It essentially consists of a series of flows and private messaging processes. The present invention is a unique messaging flow that aims at the use of asymmetric encryption in distributed swarm unmanned aerial vehicle networks. This flow is run by existing devices in the network when there are one or more devices that want to join the network newly.

Referring to Figures 1 and 2; the system according to the invention comprises at least two unmanned aerial vehicles, at least one being selected as the master unmanned aerial vehicle (10), and at least one being selected as the subordinate unmanned aerial vehicle (20). Preferably, from the system, a master unmanned aerial vehicle (10) comprises a plurality of subordinate unmanned aerial vehicles (20).

Herein, the term unmanned aerial vehicle (10) means aerial vehicles, especially drones, which can be flown remotely or fully automatically with artificial intelligence support.

Said master unmanned aerial vehicle (10) and subordinate unmanned aerial vehicle (20) are wirelessly connected to a common communication network. Said master unmanned aerial vehicle (10) is in a continuous network, and said subordinate unmanned aerial vehicle (20) can enter and exit the wireless communication network.

In the system that hosts multiple unmanned aerial vehicles, the master unmanned aerial vehicle (10) selection can be selected based on, but not limited to the pre-identification and identity number or the remaining battery level.

Said system comprises an authorization element (A) configured to generate a dynamic and context-based password. The authorization element (A) is an electronic element that generates a password, preferably directly from the digitized data or by passing said data through various processes.

While it is advantageous to provide the authorization element (A) on the master unmanned aerial vehicle (10), said authorization element (A) may be provided on the subordinate unmanned aerial vehicles (20) and transmit the obtained password to the master unmanned aerial vehicle (10). Providing the authorization element (A) on the master unmanned aerial vehicle (10) is advantageous since the master unmanned aerial vehicle (10) is constantly connected to the main communication network. The data mentioned here must be a time-variable data, and a dynamic password can only be generated depending on this. The expression of data that can change over time should not be interpreted as data that changes at any time but should be considered as a data that reveals different results at certain points.

Here, many different alternative data can be used, which can change over time. For example, various sensors can be used to provide said data. The above-mentioned sensors (S) can be temperature, pressure, position, and height sensors. The data measured by the sensor (S) mentioned here can change dynamically based on the point where the unmanned aerial vehicles are located or measurement time.

While it is advantageous to provide said sensor (S) on the master unmanned aerial vehicle (10), said sensor (S) may be provided on the subordinate unmanned aerial vehicles (20) and transmit the obtained password to the master unmanned aerial vehicle (10). Providing the sensor (S) on the master unmanned aerial vehicle (10) is advantageous since the master unmanned aerial vehicle (10) is constantly connected to the main communication network.

Alternatively, the password can be generated based on the degree of completion/success specific to the mission being performed or the incident records detected during the mission being performed. For example, various parameters such as the percentage of progress relative to the endpoint to be reached, the success of destruction according to the number of targets to be destroyed, or the number of unmanned aerial vehicles lost during the mission can be used during password generation.

In another alternative, the password can be generated using one of the instant status information of one or more of the unmanned aerial vehicles, especially the master unmanned aerial vehicle (10). For example, it can be generated using battery status, element (engine, propeller, casing, etc.) temperature, the operating speed at a given moment, speed, or the distance traveled in a given time.

The data provided here and/or the password generated from the data can be matched with a time stamp. The time stamp can be exactly when the data is read, or it can be when the password is generated. At least one of the said time-variable data can be used to generate a password, or a more secure encryption can be provided by using the same for password generation in more than one data. Herein, preferably multiple data can be data received simultaneously, as well as data collected at different moments can be used to generate passwords.

For example, said password can be generated based on the air temperature value taken on 07/21/2018, 14:46 and the battery status of the unmanned aerial vehicle taken on 07/21/2018, 14:43, and the altitude information of the unmanned aerial vehicle taken on 07/21/2018, 14:41.

The passwords generated by the authorization element (A) are transmitted to all subordinate unmanned aerial vehicles (20) connected to the communication network, at certain periodic intervals or random moments, by a communication module (H), preferably a communication module (H) provided in the master unmanned aerial vehicle (10). Each said subordinate unmanned aerial vehicle (20) comprises a further communication module (H) that can communicate wirelessly with a said communication module (H) and a memory module (M) that can save the received password.

Due to various environmental conditions or missions, at least one of the subordinate unmanned aerial vehicles (20) can disconnect the communication network in Figure la and reconnect the network at the appropriate moment, as in Figure lb.

For the subordinate unmanned aerial vehicle (20) to be reconnected to the network, the subordinate unmanned aerial vehicle (20) transmits an entry request directly to the master unmanned aerial vehicle (10) or to a further subordinate unmanned aerial vehicle that is already in the network and can communicate with the master unmanned aerial vehicle (10). Herein, along with the request, the subordinate unmanned aerial vehicle (20) can send the password it keeps in the memory unit (M) together with the request, or the password can be transmitted by the subordinate unmanned aerial vehicle (20) after the request of the master unmanned aerial vehicle (10).

At this point, a processing module (P) compares the password transmitted by the subordinate unmanned aircraft (20) that wants to be included in the communication network of a processing module (P), preferably provided on the master unmanned aerial vehicle (10), with the password generated by the authorization element (A) and if the passwords match as a result of the comparison, it generates an authorization response allowing the subordinate unmanned aerial vehicle (20) to connect to the communication network, and a rejection response in the opposite case.

As in Figure 1-lb, there may be a plurality of subordinate unmanned aerial vehicles (20) leaving the communication network. Said subordinate unmanned aerial vehicles (20) may be included in the communication network separately, or they may be included in the network together if said subordinate unmanned aerial vehicles (20) maintain the connection with each other despite disconnecting from the communication network. In order to achieve this, one of the subordinate unmanned aerial vehicles (20) disconnected from the network is selected as a "proxy". Herein, the proxy unmanned aerial vehicle communicates with the master unmanned aerial vehicle (10) and sends the connection request and the password it has stored in the memory module via its communication module.

When the proxy receives an authorization response by confirming the password sent by the unmanned aerial vehicle, said proxy unmanned aerial vehicle ensures that all client unmanned aerial vehicles are included in the communication network by sending the list of client unmanned aerial vehicles to the master unmanned aerial vehicle (10).

In a preferred embodiment of the invention, the subordinate unmanned aerial vehicles (20) comprise an altitude detection element and a control module (K) associated with said altitude detection element. The control module (K) is configured to generate a response to delete at least some of the data stored in the memory module (M). When said subordinate unmanned aerial vehicle (20) descends below a certain altitude or completely lands on the ground, it is anticipated that this is an indication that the subordinate unmanned aerial vehicle (20) may have been captured, and accordingly, the control module (2K) generates a response to at least delete the password in the memory module (M), preferably all data in the memory module (M).

Said system operates in normal operating mode when all unmanned aerial vehicles are connected to the communication network.

The normal operating process is the one in which the swarm of unmanned aerial vehicles is fully performing its predefined mission. In the meantime, no unmanned aerial vehicle has left the swarm intentionally, on a mission, or accidentally. The network connection was not interrupted, and as a result, no unmanned aerial vehicles were separated from the swarm. In this process, all devices in the swarm do their share of predefined missions.

Along with the existing mission steps, with the use of the invention, the master unmanned aerial vehicle generates up-to-date context (C) information, that is, passwords generated based on the time-variable data, at predetermined or variable periods and transmits this information to all unmanned aerial vehicles in the swarm by any of the wireless messaging methods.

The context information (C) may be generated by any of the devices in the unmanned aerial vehicle swarm, a group, or by the unmanned aerial vehicle that plays the main role (i.e., the master); it can be refreshed periodically. If the generator is not the master unmanned aerial vehicle (10), this information is assumed to be transmitted wirelessly to the master unmanned aerial vehicle (10). The content of the context information (C) may be any geographical route and location information, an environmental or internal magnitude measured by any sensor, the degree of completion/achievement specific to the mission performed, or the event or magnitude records detected during the mission performed.

The master unmanned aerial vehicle (10) can be changed periodically, and each of the available unmanned aerial vehicles can be assigned to the "master" role.

When at least one of the unmanned aerial vehicles in the swarm leaves the communication network and wants to return, the security protocol starts.

The state of emergency begins when one or more unmanned aerial vehicles leave the unmanned aerial vehicle swarm on a planned, mission, or accidental basis. In this process, the fate of the unmanned aerial vehicles leaving the swarm is not known by the swarm, and the swarm is free to continue its mission or perform different actions.

In this process, if the unmanned aerial vehicles that leave the swarm later find the existing swarm and want to reconnect to the communication network of the swarm, they must pass through an authorization check, as they can no longer be assured of their safety. This is the main function of the state of emergency. During the state of emergency, operations in the normal process are continued with the remaining unmanned aerial vehicles.

If the number of unmanned aerial vehicles leaving the swarm is more than one, but they have managed to maintain the wireless network connection among themselves, these are considered as a group of unmanned aerial vehicles, and they choose a proxy among themselves, and non-proxy unmanned aerial vehicles become clients. How this selection will take place is not defined within the scope of the invention. If there is only one unmanned aerial vehicle, then it is treated as a proxy but has no client. If there is a plurality of unmanned aerial vehicles, but if they are not connected to each other, each is treated as a clientless proxy separately.

When the unmanned aerial vehicle leaves the swarm or (in the case of a group) the proxy of the unmanned aerial vehicle reencounters with the original swarm (the definition of it is that they are within range of each other's wireless communication), if they need to re-join the swarm, it sends an authorization request message to the swarm leader. If the swarm leader is not in the coverage area of the proxy unmanned aerial vehicle, but the swarm members are in the coverage area, the member devices that receive the request message transmit the same to the master unmanned aerial vehicle (10). The authorization request message is encrypted with the asymmetric secret key of the proxy unmanned aerial vehicle. The message content is given in the figure.

Following the authorization request message of the proxy, a query message is sent by the leader. The query message is sent to request context information (C) from the proxy. The query message is encrypted with the asymmetric public key of the proxy unmanned aerial vehicle.

In response to the query message from the master unmanned aerial vehicle (10), a query response message is sent by the proxy. This message is to transmit the most recent context information (C) from the proxy unmanned aerial vehicle device to the master unmanned aerial vehicle (10). The Query Response is encrypted with the asymmetric public key of the leader. The message content is given in the figure.

At this stage, the master unmanned aerial vehicle (10) checks the accuracy of the context information (C) from the proxy by comparing the same with the records in its database. If the information is incorrect, the authorization request is denied, and both the proxy unmanned aerial vehicle and the entire group, if any, are prevented from connecting to the network. The process ends. The content of the rejection message is not important, nor does it need to be encrypted. However, if the context information (C) from the proxy is found correct, then a proxy authorization confirmation message is sent from the leader to the proxy. This message indicates to the proxy that the query was successful and gives it the symmetric session key used in routine secure communication within the swarm. If the proxy unmanned aerial vehicle does not have a client (i.e., there is only one unmanned aerial vehicle), the authorization process is completed at this stage. The proxy authorization confirmation message is encrypted with the asymmetric public key of the proxy. The message content is given in the figure. If the proxy has clients, they must also send their identity information to the leader in the next step.

Following the proxy authorization approval, the proxy sends a client list message to the master unmanned aerial vehicle (10), if any. This message contains the identification information of all other unmanned aerial vehicles in the proxy's group. This message is encrypted with the symmetric session key. The message content is given in the figure.

Finally, a client authorization confirmation message is sent from the leader to each of the clients in the attorney's group separately. These messages have the same purpose as the proxy authorization message, but with different recipients (sent directly to the clients, not the proxy). Thus, the process of device authorization and secure participation in the swarm is completed. Each client authorization confirmation message is encrypted with the recipient's asymmetric public key.

The authorization process, according to one embodiment of the invention, is shown in Figure 3. One of the subordinate unmanned aerial vehicles (20) disconnect from the communication network is selected as a "proxy". Said proxy unmanned aerial vehicle sends an authorization request to the master unmanned aerial vehicle (10). Here, the authorization request is an encryption function that involves adding an asymmetric secret key (K-), proxy identity(ID), number of the ongoing mission(MID), participation request parameter (I), a randomly generated number (N) with the end-to-end splice operator (II).

Against the authorization request, a query request is transmitted to the master unmanned aerial vehicle (10). The query request is an encryption function that involves adding the asymmetric public key (K+), the main device identity (ID), the parameter specifying information request(CR), and the time stamp (T) to each other with the end-to-end splice operator (II). Here, the parameter specifying information request (CR) is used for the password request. In response to the query request, the proxy unmanned aerial vehicle transmits the query response to the master unmanned aerial vehicle (10). The query response is an encryption function that involves adding the asymmetric public key (K+), the proxy device identity (ID), context information (C), and the time stamp (T) to each other with the end-to-end splice operator (II). Here, context information (C) is the password that was previously generated in the authorization module (A) and sent to the subordinate unmanned aerial vehicles (20), and stored in the memory module.

At this point, the password previously generated by a processing module (P) in the authorization module (A) is compared with the context information (C) from the proxy device. If there is no equality as a result of the comparison, a rejection response is generated, and the proxy device and the devices connected to the same are prevented from entering the communication network.

If the context information (C) and the password generated in the authorization module (A) match as a result of the comparison, the master unmanned aerial vehicle (20) transmits a proxy authorization confirmation to the proxy device. The proxy authorization approval is an encryption function that involves adding the asymmetric public key (K+), the main device identity (ID), the symmetric session key (Ks), and the time stamp (T) to each other with the end-to-end operator (II).

The proxy device that receives the symmetric session key (Ks) transmits the client device list to the master unmanned aerial vehicle (10). The client device list is an encryption function that involves adding the symmetric session key (Ks), proxy device identity information (ID), identity information list (L), and the time stamp (T) to each other with the end-to-end splice operator (II).

At this point, the master unmanned aerial vehicle (10) allows each client subordinate unmanned aerial vehicle (20) to connect to the communication network by sending client authorization approval. The client authorization approval is an encryption function that involves adding the asymmetric public key (K+), the main device identity (ID), the symmetric session key (Ks), and the time stamp (T) to each other with the end-to-end splice operator (II).

Claims

CLAIMS An unmanned aerial vehicle system, characterized in that, it comprises; at least one master unmanned aerial vehicle (10), at least one subordinate unmanned aerial vehicle (20), an authorization element (A) configured to generate a password that will enable a subordinate unmanned aerial vehicle (20) to connect to a network based on timevariable data, a communication module (H) configured to transmit said password to a subordinate unmanned aerial vehicle (20), a further communication module (H), configured to receive and return the password from said communication module (H), a memory module (M) associated with the subordinate unmanned aerial vehicle (20), in which the password generated by the authorization element (A) will be stored and a processing module (P) configured to compare the data from the subordinate unmanned aerial vehicle (20) with the password generated by the authorization element (A) and generate an authorization or rejection response based on this comparison. An unmanned aerial vehicle system, according to claim 1, characterized in that, it comprises at least one sensor (S) that provides instant data from the environment to generate time-variable data. An unmanned aerial vehicle system, according to claim 2, characterized in that, said sensor (S) is one of the temperature, pressure, position, and height sensors. An unmanned aerial vehicle system, according to claim 1, characterized in that, said authorization element (A) is configured to generate the password based on the degree of completion/success specific to the mission being performed or the incident records detected during the mission being performed. An unmanned aerial vehicle system, according to claim 1, characterized in that, said authorization element (A) is configured to generate the password based on the instant status of one of the unmanned aerial vehicles. An unmanned aerial vehicle system, according to claim 5, characterized in that, said instant status is at least one of the unmanned aerial vehicle's battery status, element temperature, the operating speed at a given moment, speed, or distance traveled in a given time. An unmanned aerial vehicle system, according to any of the preceding claims, characterized in that, said subordinate unmanned aerial vehicle (20) has an altitude detection element and a control module (K) configured to erase the memory unit completely or the password received from the master unmanned aerial vehicle upon descending below a certain altitude. An unmanned aerial vehicle system, according to any of the preceding claims, characterized in that, said authorization module (A) is configured to match a timevariable data and/or password with a time stamp. A computer-implemented method for the communication security of unmanned aerial vehicle systems, characterized in that, it comprises the following method steps; an authorization module (A) generating a password that will enable a subordinate unmanned aerial vehicle (20) to connect to a network, based on time-variable data and transmitting the password to the subordinate unmanned aerial vehicles (20) connected to the network by a master unmanned aerial vehicle (10), in case the subordinate unmanned aerial vehicles (20) want to exit the network and reconnect to the network, transmitting the password previously transmitted to the same by the master unmanned aerial vehicle (10) to a processing module (P) to be compared with the password generated by the authorization module (A) based on a time-variable data, generating an authorization response enabling the subordinate unmanned aerial vehicle (20) to connect to said network, if the passwords match, generating a rejection response that prevents the subordinate unmanned aerial vehicle (20) from connecting to said network if the passwords do not match. A method according to claim 9, characterized in that, said password is generated based on a sensor (S) data received from the medium.

11. A method according to claim 10, characterized in that, said data is one of temperature, pressure, position, and height data.

12. A method according to claim 9, characterized in that, said password is generated based on the degree of completion/success specific to the mission being performed or the incident records detected during the mission being performed.

13. A method according to claim 9, characterized in that, said password is generated based on the instant status of one of the unmanned aerial vehicles.

14. A method according to claim 13, characterized in that, said instant status is at least one of the unmanned aerial vehicle's battery status, element temperature, the operating speed at a given moment, speed, or the distance traveled in a given time.

15. A method according to any of claims 9-14, characterized in that, the altitude of said subordinate unmanned aerial vehicle (20) is measured and the memory unit (M) is deleted completely, or the password received from the master unmanned aerial vehicle (10) is deleted upon descending below a certain altitude.

16. A method according to any of claims 9-15, characterized in that, said time-variable data and/or password is matched with the time stamp.

17. A method according to claim 9, characterized in that, the subordinate unmanned aerial vehicle (20) that wants to connect to the network directly transmits said password to the master unmanned aerial vehicle (10).

18. A method according to claim 9, characterized in that, the subordinate unmanned aerial vehicle (20) that wants to connect to the network transmits said password to a further subordinate unmanned aerial vehicle (20) connected to the same network as the master unmanned aerial vehicle (10). A method according to claim 9, characterized in that, one of the multiple subunmanned aerial vehicles that have exited the network where the master unmanned aerial vehicle (10) is located, and yet can communicate with each other, is selected as a proxy to transmit the password to the master unmanned aerial vehicle (10). A method according to claim 19, characterized in that, if the request of the proxy subordinate unmanned aerial vehicle (20) to connect to the network is accepted, all the client subordinate unmanned aerial vehicles (20) join the network.