KR101912645B1 - Method for encryption of data and sensor node in energy harvest wireless sensor network, recording medium for performing the method - Google Patents

Abstract

The present invention discloses a sensor node, a data encryption method, and a recording medium for performing the same in an energy-collecting wireless sensor network. According to an aspect of the present invention, there is provided a sensor node comprising: a comparison determination unit comparing a residual energy amount with a threshold value; A mode selection unit for selecting an operation mode based on the comparison result; A data encryption unit for encrypting data based on the selected operation mode; And a data communication unit for transmitting the encrypted data to neighboring sensor nodes according to the set path.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a sensor node, a data encryption method, and a recording medium for performing the same in an energy-collecting wireless sensor network. 2. Description of the Related Art [0002]

The present invention relates to a sensor node, a data encryption method, and a recording medium for performing the method. More particularly, the present invention relates to an energy collection type A sensor node in a wireless sensor network, a data encryption method, and a recording medium for performing the method.

Wireless Sensor Networks (WSNs) are used in a wide range of applications from military, medical, disaster detection, ecosystem sensing, and other special applications. These sensor networks are characterized by limited battery capacity due to limited hardware characteristics. Many researches have been carried out to overcome this limited battery capacity, and various studies have been conducted in order to overcome the battery limit of the sensor node. Among them, energy-collecting sensor nodes capable of continuously charging energy are attracting attention. Energy collection In wireless sensor networks, energy-harvesting sensor nodes collect energy on a continuous and periodic basis with resources such as sun, vibration, wind, piezoelectric, and heat. Sensor nodes that collect energy based on dual solar energy are particularly preferred due to the high density of sunlight and relatively stable supply. On the other hand, sensor nodes in wireless sensor networks are vulnerable to attack. That is, the data can be taken out by an external attack, and an external attack (for example, a DoS attack) can accelerate the energy consumption of the sensor node, thereby generating a power failure state. In the existing wireless sensor network, symmetric key based encryption is used to cope with security problems. While this technique has the advantage of consuming an adaptive amount of energy, it maintains a relatively low level of security compared to other cryptographic techniques used in personal devices such as laptops or desktop computers. On the other hand, energy-harvesting sensor nodes that have overcome battery limits can achieve higher security levels using public key cryptography with sufficient energy. However, if energy charge and use are not balanced, a power outage may occur. Also, there is a trade-off between the battery life and the level of data security in the wireless sensor network as shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram illustrating the relationship between battery life and security levels of sensor nodes within a wireless sensor network.

As shown in FIG. 1, the higher the encryption level, the more energy is required in the wireless sensor network. On the contrary, the lower the encryption level, the more energy is required.

Therefore, it is necessary to study the energy saving wireless sensor network more efficiently using the stored energy of the sensor node to reduce the power failure time of the sensor node, and to increase the security level of the data transmitted between the sensor nodes It is true.

Korean Patent Publication No. 2010-0037953 (published on Apr. 12, 2010)

The present invention has been proposed in order to solve the above-mentioned problems, and it is an object of the present invention to provide an energy collecting type wireless communication system for not only enhancing the security level of data but also reducing the power failure time of the sensor node by using energy consumption of the entire network more efficiently. A sensor node in a sensor network, a data encryption method, and a recording medium for performing the method.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by one embodiment of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a sensor node including: a comparator for comparing a residual energy amount with a threshold value; A mode selection unit for selecting an operation mode based on the comparison result; A data encryption unit for encrypting data based on the selected operation mode; And a data communication unit for transmitting the encrypted data to neighboring sensor nodes according to the set path.

Wherein the mode selection unit selects an energy-rich (ER) mode when the residual energy amount is greater than a threshold value as a result of the comparison by the comparison determination unit, and when the residual energy amount is less than a threshold value, Saving mode can be selected.

Wherein the data encryption unit encrypts the sensed data using a symmetric key technique when an ES (energy-saving) mode is selected as a result of the operation mode selection of the mode selection unit, -Rich) mode is selected, the sensed data can be encrypted using the public key technique.

When the energy saving mode is selected as a result of the operation mode selection of the device mode selection unit and the encrypted data received from the neighboring sensor node is encrypted by the symmetric key technique, (Energy-Rich) mode is selected as a result of the operation mode selection of the mode selection unit. If the encrypted data received from the neighboring sensor node is encrypted by the symmetric key technique, data is encrypted using the public key technique Can be re-encrypted.

Wherein the data encryption unit selects one of the operation mode selection result of the mode selection unit, the Energy Saving (ES) mode or the energy-rich (ER) mode and the encrypted data received from the neighboring sensor node The data communication unit can relay the encrypted data to the neighboring sensor node without re-encrypting the data if it is encrypted by the public key technique.

According to another aspect of the present invention, there is provided a method of encrypting data in an energy-collecting wireless sensor network, the method comprising: comparing a residual energy amount with a threshold value; The sensor node selecting an operation mode based on the comparison result; The sensor node proceeds to encrypt the data based on the selected operation mode; And transmitting the encrypted data to a neighboring sensor node according to the set path.

Energy-saving mode is selected when the residual energy amount is larger than the threshold value as a result of the comparison, and when the remaining energy amount is smaller than the threshold value, energy-saving (ES) Mode can be selected.

Wherein the step of encrypting the data comprises encrypting the sensed data using a symmetric key technique when the energy saving mode is selected as a result of the operation mode selection, Rich mode is selected, the sensed data can be encrypted using the public key technique.

In the step of encrypting the data, when the energy-saving mode is selected as a result of the operation mode selection and the encrypted data received from the neighboring sensor node is encrypted using the symmetric key technique, (Energy-Rich) mode is selected as a result of the operation mode selection. If the encrypted data received from the adjacent sensor node is encrypted by the symmetric key technique, the data is re-encrypted using the public key technique You can encrypt it.

In the step of encrypting the data, an operation mode selected from among the energy-saving (ES) mode or the energy-rich (ER) mode is selected as a result of the operation mode selection, In the step of transmitting the encrypted data to the neighboring sensor node according to the set path without re-encrypting the data when the data is encrypted by the public key technique, the encrypted data can be relayed to the neighboring sensor node.

According to another aspect of the present invention, there is provided a computer readable recording medium storing a computer program for performing a data encryption method.

According to an aspect of the present invention, energy consumption in the entire network can be more efficiently used, thereby minimizing the power failure state of the sensor node and enhancing the security level of data to be transmitted.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the specific details for carrying out the invention, And shall not be construed as limited to the matters described.
1 schematically illustrates the relationship between battery life and security levels of sensor nodes within a wireless sensor network,
FIG. 2 illustrates features of a public key encryption scheme and a symmetric key encryption scheme; FIG.
FIG. 3 is a view schematically showing a configuration of an energy-collecting wireless sensor network according to an embodiment of the present invention;
FIG. 4 schematically illustrates a configuration of a sensor node according to an embodiment of the present invention. FIG.
FIG. 5 is a diagram schematically illustrating operation mode setting based on a threshold value and a residual energy amount in an energy-collecting wireless sensor network according to an embodiment of the present invention; FIG.
6 to 7 are diagrams showing pseudo-code of a data encryption technique according to an embodiment of the present invention,
8 is a flowchart illustrating a data encryption method according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Throughout the specification, when an element is referred to as " comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. In addition, the term "Quot; and " part " refer to a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

2 is a diagram illustrating features of a public key encryption scheme and a symmetric key encryption scheme.

First, prior to describing the present invention, the public key encryption scheme and the symmetric key encryption scheme will be described as follows.

In wireless sensor networks, data encryption schemes can be largely public key cryptography and symmetric key cryptography.

2, in a symmetric key encryption scheme, a transmitting device (a sensor node that transmits data) encrypts a plaintext with an encryption key using a symmetric key, and a receiving device (a sensor node that receives data) The ciphertext is decrypted into a plaintext using the same key as that of the transmitter.

Where M is a plaintext, C is a ciphertext, K is a symmetric key, E is a cryptographic function, and D is a decryption function. Since symmetric key cryptography uses the same key (secret key) for encryption and decryption, two sensor nodes exchanging data must maintain their own keys. To relay the data received by the receiving device, the sensor node decrypts the received data and re-encrypts it using a key corresponding to the new destination node. At this time, most symmetric key encryption schemes have faster execution speed and less energy consumption than public key encryption schemes. However, since re-decryption and re-encryption are required at all nodes, the energy consumption of other nodes that need to relay the data is not negligible. In addition, there is a problem that a key (secret key) can be exposed due to a feature that a sensor node in a wireless sensor network can be physically easily taken and attacked. At this time, the public key encryption scheme may be an Elliptic Curve Integrated Encryption Scheme (ECIES) algorithm. In other words, the symmetric key encryption scheme is characterized in that the encryption key used for encryption and the decryption key used for decryption are the same, and the key must be secretly managed so as not to be exposed except the transmitting apparatus and the receiving apparatus. The symmetric key cryptosystem can be used to construct an efficient cryptosystem because the key used is short and the speed is fast. The symmetric key encryption scheme is a combination of simple substitution (substitution) and transposition (shuffling) in the internal structure of the algorithm, so that the algorithm can be easily developed and operated quickly in a computer system.

On the other hand, in the public key cryptosystem, a transmitting apparatus encrypts a plain text with a ciphertext using a public key or a private key. Thereafter, when the received data is encrypted using the public key, the receiving device decrypts the cipher text using the private key. If the received data is encrypted using the private key, the receiving device decrypts the cipher text using the public key can do. This decoding process is shown in Equation 2 below.

Where M is a plaintext, C is a ciphertext, K ⁺ is a public key, K ^- is a private key, E is a cryptographic function, and D is a decryption function. At this time, when all the sensor nodes maintain the same public key and transmit the encrypted data using the public key, the sink node decrypts the data using its own private key. At this point, the relay node receiving the data to be relayed to the sink node can transmit it without re-encrypting it. Most public-key cryptography is CPU-intensive and therefore consumes more energy than symmetric-key cryptography. However, since the data encrypted using the public key cryptosystem is almost impossible to be decrypted by a malicious hacker or a program, and the leakage of the key (private key) is scarcely generated, the data reliability is relatively higher than that of the symmetric key cryptography Can be guaranteed. However, since the amount of encrypted data is relatively large, energy consumption for data transmission is also considerably higher than that of symmetric key cryptography. On the other hand, in the case of receiving encrypted data using public key cryptography, since the relay node transmits data without re-encryption, energy consumption in the entire network is lower than that of symmetric key cryptography in terms of energy consumption . At this time, the symmetric key encryption scheme may be an AES (Advanced Encryption Standard) algorithm. In other words, unlike the secret key cryptography, the public key cryptography can perform secret communication using a different key between the transmitting device and the receiving device. The transmitting apparatus encrypts data using information corresponding to the public key of the receiving apparatus, transmits the encrypted data through the network, and the receiving apparatus decrypts the encrypted data using the secret key corresponding to the public key of the transmitting apparatus to recover the plain text. Public key cryptography has the advantage of secure communication through cryptography even when keys are not shared with other devices. Each device discloses a key to be used for transmission to the user and secretly holds a key capable of decrypting the information encrypted with the disclosed key information so that anyone can encrypt it, but the device having the secret key corresponding to the public key It can be decoded only.

The sensor node according to the present invention transmits data sensed by itself or data received from neighboring sensor nodes to a public key encryption scheme or a symmetric key encryption scheme based on the selected operation mode in consideration of the remaining energy amount of the battery The data can be encrypted through any one of encryption methods. More specifically, the sensor node may select an operation mode according to the amount of remaining energy, and may encrypt the sensed data through any one of a public key encryption scheme and a symmetric key encryption scheme. In addition, the sensor node selects the operation mode according to the amount of energy remaining, confirms the encryption technique of the data received from the neighboring sensor node, encrypts the data with the public key encryption technique, or simply relays the received data without encryption have.

In other words, the sensor node does not encrypt the data using only one of the encryption schemes described above in data encryption, and does not encrypt any of the encryption schemes described above (for example, considering the residual energy amount of the sensor node) By choosing one technique to cope dynamically, it can reduce the energy consumption of the whole network and improve the security level.

 FIG. 3 is a view schematically showing a configuration of an energy-collecting wireless sensor network according to an embodiment of the present invention.

The energy collecting wireless sensor network according to the present invention may be a solar energy based energy collecting wireless sensor network. The energy-harvesting wireless sensor network may include a plurality of sensor nodes for collecting, encrypting, and transmitting data to the sink node.

As shown in FIG. 3, the sensor node constitutes a solar energy-based energy-harvesting wireless sensor network. The sensor node may be an energy collection sensor node that collects energy. The sensor node can collect energy from the surrounding environment. For example, the sensor node may include a solar panel and may collect energy using solar light. In addition, the sensor nodes can be randomly placed in random numbers ranging from several tens to several thousands in a wide area.

The sensor node senses data through one or more sensors, transmits the sensed data to another node, or transmits data received from another node to another node. In this case, the sensor node that transmits the sensed data to the neighboring node is referred to as a sensing node, the sensor node that transmits data received from the neighboring node to another neighbor node is referred to as a relay node (relay node) The arriving node may be referred to as a sink node. The sink node can collect data sent by neighbor nodes (relay nodes), process the data, and send the data to the server node.

In the meantime, in describing the present embodiment, it is assumed that the sensor node included in the energy collection type sensor network is a sensor node that collects energy based on solar energy. However, the present invention is not limited to this, and the sensor node may be a sensor node that continuously and periodically collects energy from vibration, wind, piezoelectric, heat, and other resources.

According to the present invention, each sensor node selects its own operation mode according to the level of energy remaining in its battery, encrypts data using different encryption algorithms according to the selected operation mode, and transmits the encrypted data . The sensor node can itself select one of two different operation modes. At this time, the different operation modes may be an Energy Saving (ES) mode and / or an Energy-Rich (ER) mode. For example, if the amount of energy remaining in the sensor node is less than a certain threshold value, the sensor node may select the ES mode to concentrate on its own energy saving instead of lowering the security level, and encrypt the data using the symmetric key encryption technique . At this time, the remaining energy amount may be the remaining energy amount of the battery accumulated by the sensor node. In describing the present embodiment, the threshold may be arbitrarily set and used in order to enable the sensor nodes in the wireless sensor network to minimize the power failure state by saving energy and to improve the security level of the transmitted data. . However, the present invention is not limited to this, and the threshold value can be determined on the basis of the result of energy consumption analysis in one sensor node. That is, the threshold value may be arbitrarily determined in consideration of energy consumption in the entire network. At this time, a more detailed description related to the determination of the threshold value will be described later with reference to FIG. Referring to FIG. 3, when the received data is encrypted using the symmetric key encryption scheme, the sensor node in the ES mode decrypts and re-encrypts the corresponding data using the symmetric key encryption scheme. At this time, if the received data is encrypted using the public key encryption method, the received data is simply relayed to the neighboring sensor node without decoding or re-encryption. On the other hand, the sensor node that has selected the ES mode encrypts its sensed data by using a symmetric key encryption scheme for energy saving.

On the other hand, if the amount of energy remaining in the sensor node is greater than a certain threshold value, the sensor node can self-select the operation mode as the ER mode and encrypt the data by using the public key encryption method because the sensor node itself has a sufficient amount of energy. Referring to FIG. 3, the sensor node in the ER mode re-encrypts the received data using the public key encryption scheme when the received data is encrypted using the symmetric key encryption scheme. At this time, if the received data is encrypted using the public key cryptosystem, the received data is simply relayed to the neighboring sensor node without re-encryption. On the other hand, the sensor node that has selected the ER mode encrypts the data that it has sensed by using the public key cryptosystem to improve the security level.

As described above, since the sensor node selected by the ER mode consumes energy and encrypts the data using the public key cryptosystem, it is not necessary to decrypt and re-encrypt the data in all the relay nodes in which the encrypted data is relayed The burden of energy consumption at the relay node is relaxed, and energy consumption in the entire network can be efficiently performed. That is, as the number of sensor nodes increases, the energy consumption of the entire network can be reduced. In addition, the data encrypted with the public key cryptosystem can have a higher security level than the data encrypted with the symmetric key cryptosystem, thereby improving the security level of the data transmitted through the network. On the other hand, the sensor nodes that have selected the ES mode can minimize the power failure of the sensor node because the sensor node encrypts the data using the symmetric key cryptography, which has a relatively high processing speed and relatively low energy consumption compared to the public key cryptography.

As described above, the sensor nodes included in the energy-collecting wireless sensor network according to the present embodiment do not encrypt data using only one of the encryption schemes described above in the data encryption, The energy consumption of the entire network can be reduced and the level of security can be further improved since any one of the above encryption schemes is selected and dynamically coped with.

4 is a diagram schematically showing a configuration of a sensor node according to an embodiment of the present invention.

4, the sensor node 400 in the energy-collecting wireless sensor network according to the present invention includes a comparison determination unit 410, a mode selection unit 430, a data encryption unit 450, and a data communication unit 470 ). In the description of this embodiment, it is assumed that the sensor node 400 measures the amount of remaining energy of the battery through the battery amount measuring sensor and stores it in a separate memory.

The comparison determination unit 410 may compare the residual energy amount with a threshold value. At this time, the residual energy amount may mean the amount of energy remaining in the battery of the sensor node 400. [ The threshold may be set and used arbitrarily to enable the sensor nodes 400 in the wireless sensor network to save energy to minimize the outage and to increase the level of security of the data being transmitted. However, the present invention is not limited to this, and the threshold value can be determined based on the result of the energy consumption analysis in one sensor node 400. That is, the threshold value may be arbitrarily determined in consideration of energy consumption in the entire network.

The mode selection unit 430 can select the operation mode based on the comparison result of the residual energy amount and the threshold value. The mode selection unit 430 can select the operation mode according to the comparison result of the comparison determination unit 410. If the remaining energy amount is larger than the threshold value as a result of the comparison by the comparison determination unit 410, the mode selection unit 430 can select the ER (energy-rich) mode. The mode selection unit 430 can select the energy saving mode when the residual energy amount is smaller than the threshold value as a result of the comparison by the comparison determination unit 410. [

The data encryption unit 450 can proceed to encrypt data based on the selected operation mode. The data encryption unit 450 can encrypt the sensed data using the symmetric key technique when the energy saving mode is selected as a result of the operation mode selection of the mode selection unit 430. [ The data encryption unit 450 can encrypt the sensed data using the public key technique when the ER (energy-rich) mode is selected as a result of the operation mode selection of the mode selection unit 430. [ The data encryption unit 450 selects the energy saving mode as a result of the operation mode selection of the mode selection unit 430 and transmits the encrypted data received from the neighboring sensor node 400 to the encryption / , The data can be re-encrypted using the symmetric key technique. Also, the data encryption unit 450 selects an energy-rich (ER) mode as a result of the operation mode selection of the mode selection unit 430. When the encrypted data received from the neighboring sensor node 400 is a symmetric key technique It is possible to re-encrypt the data using the public key technique.

Meanwhile, the data encryption unit 450 selects one of the operation modes of the mode selection unit 430, the Energy Saving (ES) mode or the Energy-Rich (ER) And does not re-encrypt the data if the encrypted data received from the node 400 is encrypted with the public key technique. At this time, the data communication unit 470 simply relays the encrypted data to the neighboring sensor node 400 through the data encryption unit 450.

The data communication unit 470 can transmit the encrypted data to the neighboring sensor node 400 according to the set path.

FIG. 5 is a diagram schematically illustrating operation mode setting based on a threshold value and a residual energy amount in an energy-collecting wireless sensor network according to an embodiment of the present invention. FIGS. FIG. 4 is a diagram illustrating a data encryption technique according to an embodiment in pseudo-code. FIG.

All sensor nodes in the wireless sensor network detect events, perform data processing, and transmit data. Therefore, energy consumption can be divided into three parts: event detection, data processing, and communication (data transmission and reception). At this time, the energy consumed for event detection can be determined according to the application type of the sensor, the complexity of sensing, and the like. The energy consumed for event detection is mostly consumed in the analog-to-digital converter and can be determined according to Equation (3) below.

Where F _s is the sampling rate and ENOB is the number of valid bits.

The energy consumption according to the data processing can be determined according to the clock speed, the average electric capacity, the supply voltage, the thermal voltage and the like.

One sensor node consumes most of its energy for communication. At this time, the power consumption of the communication E _c can be determined according to Equation (4) below.

Where E _o is the output transmit power and E _tx and E _rx are the power consumption of the transmitting and receiving devices, respectively. In order to accurately analyze the energy consumption, all three parts should be considered. However, in the embodiment according to the present invention, communication energy consumption and data processing will be more specifically focused on data encryption and decryption.

The threshold according to this embodiment may be related to the energy consumption of the entire network. That is, when the threshold value is high, many sensor nodes are operated in the ES mode, the security level is reduced, and the charged energy may be wasted exceeding the battery maximum capacity. Conversely, when the threshold is low, many sensor nodes operate in the ER mode, and the security level increases, but the energy consumption of the sensor node increases, so that the power failure time of some sensor nodes may increase.

Therefore, in the solar energy-based wireless sensor network according to the present embodiment, both the energy absorption rate of the solar battery and the energy consumption rate of the network as the energy output model should be considered as the energy input model. The energy absorption rate of a solar battery as an energy input model may vary depending on the location where the sensor node is deployed, the weather, and the season. As an energy output model, the energy consumption rate of a network can be determined according to data detection rate, data transmission rate, and duty cycle. However, most of these factors can not be accurately predicted. Therefore, a more effective threshold value can be determined through the following process.

First, the power P _solar (i) the solar energy based sensor node n _i the average charging rate of, when the P _sys (i) that the average power consumption rate of the same sensor nodes, P _solar (i) and P _sys (i) is It can be estimated using moving averages when the network is in operation. I know the current sensor node n _i the amount of energy (e. G., _Residual E _(i)) available to the elapsed time until the battery is fully charged can be calculated by equation 5 below.

Here, C (i) is the battery capacity of the node n _i . The battery can only be charged if P _solar (i)> P _sys (i). However, P _solar (i)> P _sys (i) means that the average energy consumption rate of the sensor node must be less than its average solar energy charge rate, otherwise the node must be hibernated. Even if P _solar (i) can not be controlled, P _sys (i) can be roughly controlled by adjusting duty cycle DC (i) of sensor node n _i . This is because P _sys (i) is an inverse function of DC (i). Therefore, P _solar (i)> P _sys (i) can be satisfied by determining the upper limit of DC (i).

Although the solar energy is not available at night and is different each time, any outage time may not be expected if the current battery remaining amount meets the condition of Equation 6 below.

를 충족시킬 수 있다. 이것은 만약, 배터리량이 최소한

인 에너지를 지니고 있는 경우에 네트워크는 어떠한 패턴의 기상 또는 에너지 사용에 대해서도 예기치 않은 정전 상태를 겪지 않고 동작할 수 있다. 이때, 상술한

는 임계치(E_residual(i))로 결정되어 사용될 수 있다. This can be true even in situations where the solar energy charge reaches its final moment, T _Full (E _residual (i)). By solving Equations 5 and 6 above,

Can be satisfied. This means that if the battery

, The network can operate without experiencing unexpected power outages for any pattern of weather or energy use. At this time,

Can be determined and used as a threshold value (E _residual (i)).

Referring to FIG. 5, the sensor node can not guarantee that if E _{residual (i)} is less than E _{threshold (i)} , the wireless sensor network operates without unexpected power outage time. Thus, the sensor node can operate in the ES mode to save energy. On the other hand, since the sensor node has sufficient energy to perform additional tasks when E _{residual (i)} is larger than E _{threshold (i)} , the sensor node operates in the ER mode, Additional benefits of energy-harvesting wireless sensor networks can be sought.

는 동작 모드의 잦은 변경을 방지하기 위한 에너지 윈도우, AES는 대칭키 암호화 기법의 알고리즘, ECIES는 공개키 암호화 기법의 알고리즘, period는 정기 호출 주기를 의미할 수 있다.Once the sensor node is in a solar energy based energy-harvesting wireless sensor network, the node n _i may execute the pseudo code as shown in FIG. 6 to determine its original mode of operation by itself. After executing the pseudo code as shown in FIG. 6, the sensor node can periodically activate the pseudo code as shown in FIG. 6 to 7, E _{residual (i)} is the residual energy amount of the sensor node n _i , E _{threshold (i)} is the threshold value (P _sys (i) / P _solar ), M _i is the numerical value according to the operation mode change (that is, when the sensor node is operating in the ER mode in case of 1 and the sensor node is operating as the ES node in case of 0)

AES is the symmetric key encryption algorithm, ECIES is the public key encryption algorithm, and period is the periodic paging cycle.

)를 사용하여 반복되는 동작 모드 변화의 효과를 완화시킬 수 있다. On the other hand, it may be necessary to prevent all sensor nodes in the wireless sensor network from frequently and repeatedly fluctuating. In Figure 6-7, and 1 when operating in a m _i sensor node ER mode, If it is not, when said zero mode of operation of the sensor node n _i is, the above-mentioned mode m _i is E _{residual (i)} And E _{threshold (i)} . However, comparing E _{residual (i)} with the correct value of E _{threshold (i)} may lead to frequent changes of m _i . Because any sensor node n _i is assuming that the start operation immediately ER mode, the E _{residual (i)} is larger than E _{threshold (i),} the sensor node n _i is a very rare case having sufficient energy, E _{residual (i)} May fall below the threshold within a very short period of time. A similar situation may occur when the sensor node initiates operation in ES mode as soon as E _{residual (i)} is less than E _{threshold (i)} . Changes in the repetitive mode of operation such as this can degrade the reliability and performance of the network,

) Can be used to mitigate the effect of repeated operation mode changes.

8 is a flowchart illustrating a data encryption method according to an embodiment of the present invention.

As shown in FIG. 8, a data encryption method in a solar energy-based collective wireless sensor network is as follows.

First, the sensor node 400 compares the residual energy amount with a threshold value (810). At this time, the residual energy amount may mean the amount of energy remaining in the battery of the sensor node 400. [ The threshold may be set and used arbitrarily to enable the sensor nodes 400 in the wireless sensor network to save energy to minimize the outage and to increase the level of security of the data being transmitted. However, the present invention is not limited to this, and the threshold value can be determined based on the result of the energy consumption analysis in one sensor node 400. That is, the threshold value may be arbitrarily determined in consideration of energy consumption in the entire network.

The sensor node 400 may select the operation mode based on the comparison result of the residual energy amount and the threshold value (830). The sensor node 400 can select the operation mode according to the result of the comparison of the residual energy amount and the threshold value. The sensor node 400 can select the ER (energy-rich) mode when the remaining energy amount is greater than the threshold value as a result of comparing the remaining energy amount and the threshold value. The sensor node 400 can select the energy saving mode (ES) when the residual energy amount is less than the threshold value as a result of comparison between the residual energy amount and the threshold value.

The sensor node 400 may proceed with encryption of data based on the selected mode of operation (850). As a result of the selection of the operation mode, the sensor node 400 can encrypt the sensed data using the symmetric key technique when the ES (energy-saving) mode is selected. As a result of the selection of the operation mode, the sensor node 400 can encrypt the sensed data using the public key technique when the energy-rich (ER) mode is selected. When the energy-saving mode is selected as the result of the operation mode selection and the encrypted data received from the neighboring sensor node 400 is encrypted using the symmetric key technique, the sensor node 400 transmits the data Can be re-encrypted. When the energy-rich mode is selected as a result of the operation mode selection and the encrypted data received from the neighboring sensor node 400 is encrypted using the symmetric key technique, the sensor node 400 transmits the data using the public key technique Can be re-encrypted.

As a result of the selection of the operation mode, the sensor node 400 selects one of the energy-saving (ES) mode and the energy-rich (ER) mode, If the data is encrypted using the public key technique, the received data can be simply relayed to the neighboring sensor node 400 without re-encrypting the data.

The sensor node 400 transmits the encrypted data to the neighboring sensor node 400 according to the set path (870).

As described above, there is an effect that both the encryption level and the energy consumption efficiency of the data transmitted in the energy-based wireless sensor network based on the solar energy can be improved.

The methods according to embodiments of the present invention may be implemented in an application or implemented in the form of program instructions that may be executed through various computer components and recorded on a computer readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer-readable recording medium may be ones that are specially designed and configured for the present invention and are known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules for performing the processing according to the present invention, and vice versa.

While the specification contains many features, such features should not be construed as limiting the scope of the invention or the scope of the claims. In addition, the features described in the individual embodiments herein may be combined and implemented in a single embodiment. On the contrary, the various features described in the singular embodiments may be individually implemented in various embodiments or properly combined.

Although the operations are described in a particular order in the figures, it should be understood that such operations are performed in a particular order as shown, or that all described operations are performed in a series of sequential orders, or to obtain the desired result. In certain circumstances, multitasking and parallel processing may be advantageous. It should also be understood that the division of various system components in the above embodiments does not require such distinction in all embodiments. The above-described application components and systems can generally be packaged into a single software product or multiple software products.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

400: sensor node
410:
430:
450: Data encryption unit
470: Data communication section

Claims (11)

A comparison judging unit for comparing the residual energy amount with a threshold value;
A mode selection unit for selecting an operation mode based on the comparison result;
A data encryption unit for encrypting data based on the selected operation mode; And
And a data communication unit for transmitting the encrypted data to neighboring sensor nodes according to a set path,
Wherein the mode selector comprises:
If the remaining energy amount is smaller than the threshold value as a result of the comparison, the energy saving mode is selected,
When the remaining energy amount is larger than the threshold value as a result of the comparison, the ER (energy-rich) mode is selected,
The data encryption unit includes:
As a result of the operation mode selection of the mode selection unit, when the energy saving mode is selected, the sensed data is encrypted using the symmetric key technique,
If the Energy-Rich (ER) mode is selected as a result of the operation mode selection of the mode selection unit, the sensed data is encrypted using a public key technique,
When the ES (energy-saving) mode is selected and the encrypted data received from the neighboring sensor node is encrypted by the symmetric key technique, the data is re-encrypted using the symmetric key technique,
When the ER (energy-rich) mode is selected and the encrypted data received from the neighboring sensor node is encrypted using the symmetric key technique, the sensor node re-encrypts the data using the public key technique. delete delete delete The method according to claim 1,
The data encryption unit includes:
As a result of the operation mode selection result of the mode selection unit, any one of the operation modes of the Energy Saving (ES) mode or the Energy-Rich (ER) mode is selected and the encrypted data received from the neighboring sensor node is encrypted It does not re-encrypt the data,
And the data communication unit relays the encrypted data to neighboring sensor nodes. A method of data encryption in an energy-harvesting wireless sensor network,
Comparing the residual energy amount with a threshold value of the sensor node;
The sensor node selecting an operation mode based on the comparison result;
The sensor node proceeds to encrypt the data based on the selected operation mode; And
And transmitting, by the sensor node, the encrypted data to the neighboring sensor node according to the set path,
In the step of selecting the operation mode,
As a result of the comparison, when the remaining energy amount is smaller than the threshold value, the energy saving mode is selected,
If the residual energy amount is greater than the threshold value as a result of the comparison, the ER (energy-rich) mode is selected,
In the step of encrypting the data,
As a result of the selection of the operation mode, when the ES (energy-saving) mode is selected, the sensed data is encrypted using the symmetric key technique,
As a result of the selection of the operation mode, when the energy-rich (ER) mode is selected, the sensed data is encrypted using a public key technique,
When the ES (energy-saving) mode is selected and the encrypted data received from the neighboring sensor node is encrypted by the symmetric key technique, the data is re-encrypted using the symmetric key technique,
Wherein the ER (Energy-Rich) mode is selected and the encrypted data received from the neighboring sensor node is encrypted by the symmetric key technique, the data is re-encrypted using the public key technique. delete delete delete The method according to claim 6,
In the step of encrypting the data,
As a result of the operation mode selection, when one of the operation modes of the Energy Saving (ES) mode or Energy-Rich (ER) mode is selected and the encrypted data received from the neighboring sensor node is encrypted by the public key technique Without re-encryption,
In the step of transmitting the encrypted data to a neighboring sensor node according to a set path,
And relaying the encrypted data to a neighboring sensor node. A computer-readable recording medium on which a computer program is recorded, for performing the data encryption method according to any one of claims 6 to 10.

Images