WO2019086969A1

WO2019086969A1 - Condition monitoring device and method for secure communication

Info

Publication number: WO2019086969A1
Application number: PCT/IB2018/056899
Authority: WO
Inventors: Apala Ray; Thomas Locher; Aurelien MONOT
Original assignee: Abb Schweiz Ag
Priority date: 2017-11-01
Filing date: 2018-09-11
Publication date: 2019-05-09

Abstract

Techniques for establishing communication between a condition monitoring device of an electrical machine and a portable device for monitoring condition of the electrical machine are described. The condition monitoring device and the portable device are respectively configured to measure at least one of electrical and mechanical parameter of the electrical machine. The condition monitoring device generates a first encryption key using measurement data of the parameter from the first sensor. Further, the condition monitoring device receives a handshake message from the portable device. Subsequently, the condition monitoring device authenticates the handshake message using the first encryption key and establishes communication with the portable device.

Description

CONDITION MONITORING DEVICE AND METHOD FOR SECURE COMMUNICATION

THEREFOR TECHNICAL FIELD

[0001] The present subject matter relates, in general, to industrial systems and, in particular, to monitoring condition of electrical machines used in industrial systems.

BACKGROUND

[0002] An industrial system can be used to monitor and control one or more tasks performed in an industrial plant. Various industries, such as automobile industry, metallurgical industry, chemical industry, petrochemical industry, and power generation industry can utilize industrial systems to reduce human monitoring. One or more electrical machines may be used in the industrial systems. As an example, an electrical motor may be used in an industrial system to operate a pump to supply water to a boiler in a thermal power plant.

[0003] The condition of the electrical machines is typically monitored using condition monitoring devices. A condition monitoring device includes one or more sensors that measure one or more parameters related to the functioning of an electrical machine. These parameters may be shared with a portable device for further processing. The condition monitoring device and the portable device may be paired with each other for ensuring secure and reliable communication.

[0004] For example, the condition monitoring device and the portable device may authenticate each other before beginning the communication to reduce security risks, such as unauthorized data breaches. This authentication generally involves the creation and verification of encryption keys. Typically, industrial systems rely on symmetric key cryptography for authentication. Symmetric key cryptography uses the same key to both encrypt and decrypt digital data. For this, the key is pre-shared between the condition monitoring device and the portable device. As the symmetric key is pre-shared, it is easy for trespassers to acquire the symmetric key from these devices in the industrial system, which could lead to security breaches.

[0005] On the other hand, in some cases, the condition monitoring device may generate a key dynamically for the authentication. However, owing to its low computational capability, the generated key may not be strong, i.e., may be less complex and simple to hack. To use a strong key for authentication, sometimes, the key may be generated on a machine with greater computational capability, such as a laptop. Upon generation, such a key may be transferred to the condition monitoring device to be used for authentication. However, this process is time-consuming and error-prone.

[0006] In some other cases, manual configuration of keys is used for the authentication, which requires a person to manually set up a secure communication. This may not be feasible at all times, and may lead to errors and security breaches.

BRIEF DESCRIPTION OF FIGURES

[0007] The features, aspects, and advantages of the present subject matter will be better understood with regard to the following description, and accompanying figures. The use of the same reference numbers in different figures indicates similar or identical features and components.

[0008] Fig. 1 illustrates an industrial system depicting a condition monitoring device for communicating a condition of an electrical machine with a portable device, in accordance with implementations of the present subject matter.

[0009] Fig. 2 illustrates a block diagram depicting a condition monitoring device of an electrical machine and a portable device, in accordance with implementations of the present subject matter.

[0010] Fig. 3 illustrates a method for an initialization of a condition monitoring device, in accordance with implementations of the present subject matter. [0011] Fig. 4 illustrates a method for an initialization of the portable device, in accordance with implementations of the present subject matter.

DETAILED DESCRIPTION

[0012] The present subject matter relates to monitoring condition of an electrical machine in industrial systems. With the systems and methods of the present subject matter, condition monitoring devices and portable devices can perform authentication securely and quickly to initiate communication of parameters related to an electrical machine.

[0013] In an implementation of the present subject matter, a condition monitoring device of an electrical machine for communicating a condition of the electrical machine with a portable device is provided. The condition monitoring device is attached to a body of the electrical machine. The portable device is brought proximal to the condition monitoring device to receive the condition of the electrical machine via wireless means. The condition monitoring device and the portable device are respectively configured to measure at least one of an electrical parameter and a mechanical parameter of the electrical machine.

[0014] The condition monitoring device comprises a plurality of sensors. The plurality of sensors comprises at least one first sensor for measuring the at least one of an electrical parameter and a mechanical parameter of the electrical machine. The condition monitoring device also comprises one or more processors configured to receive measurements from the plurality of sensors, and determine the condition of the electrical machine based on the received measurements. The condition monitoring device further comprises a network interface for communicating the condition of the electrical machine to the portable device.

[0015] The one or more processors are configured to generate a first encryption key based on measurement data of the at least one of an electrical parameter and the mechanical parameter of the electrical machine from the at least one first sensor. The processors also receive a handshake message from the portable device via the network interface and authenticate the handshake message based on the generated first encryption key. After authentication, the processor can establish communication with the portable device via the network interface.

[0016] The present subject matter provides a secure technique for authentication of the condition monitoring device and the portable device. Since the first encryption key is generated based on the electrical parameters and mechanical parameters of the electrical machine, it cannot be replicated without measuring the exact same electrical parameters and mechanical parameters of the electrical machine. Hence, by using the measurement of the electrical parameters and mechanical parameters of the electrical machine to generate an encryption key, the authentication process is made more secure.

[0017] The above and other features, aspects, and advantages of the subject matter will be better explained with regard to the following description, appended claims, and accompanying figures.

[0018] Fig. 1 illustrates an industrial system 100 depicting a condition monitoring device 102 for communicating a condition of an electrical machine 106 with a portable device 104, in accordance with an implementation of the present subject matter.

[0019] The condition monitoring device 102 is attached to a body of the electrical machine 106 for communicating a condition of the electrical machine 106 with the portable device 104. Such a communication may be performed when the portable device 104 is in proximity to the electrical machine 106. The portable device 104 may be, for example, a smartphone, a personal digital assistant (PDA), a laptop, a tablet computer, or the like.

[0020] The condition monitoring device 102 may be implemented as a computing device comprising a plurality of sensors, one or more processors, memories, network interfaces, and the like. [0021] The condition of the electrical machine 106 may refer to at least one of a working state, an electrical parameter, and a mechanical parameter of the electrical machine 106. The working state of the electrical machine 106 may be an on/off/sleep state of the electrical machine 106. The electrical parameter may refer to current, voltage, power, resistivity, permeability, noise and amplitude distortion, magnetic field, among others. The mechanical parameter may be, for example, vibration, temperature, and acoustic signal of the electrical machine 106, and the like.

[0022] The condition monitoring device 102 is configured to measure at least one of an electrical parameter and a mechanical parameter of the electrical machine 106. Hereinafter, the at least one of an electrical parameter and a mechanical parameter of the electrical machine 106 are collectively referred to as parameters of the electrical machine 106.

[0023] The condition monitoring device 102 has two states, an initial state and a second state. In the initial state, the condition monitoring device 102 is not connected to any portable device. In the second state, the condition monitoring device 102 has established a communication session with a portable device 104. The condition monitoring device 102 changes from the initial state to the second state after it authenticates the portable device 104. In one example, the condition monitoring device 102 is attached to the electrical machine 106. For example, the condition monitoring device 102 can be mounted on the body of the electrical machine 106.

[0024] The portable device 104 comprises a plurality of sensors 108 for measuring the parameters of the electrical machine 106. Similar to the portable device 104, the condition monitoring device 102 also includes a plurality of sensors (not shown in Fig. 1 ) to measure the parameters. In operation, to perform the authentication, the condition monitoring device 102 and the portable device 104 may generate their respective encryption keys based on the measured parameters of the electrical machine 108. The condition monitoring device 102 and the portable device 104 may then exchange data encrypted by their respective encryption keys. Since both encryption keys were generated using the same measured parameters, each device would be able to decode the encrypted data received from the other device using its own encryption key and thereby authenticate the other device. Various implementations for authentication are described further with reference to Fig. 2.

[0025] Fig. 2 illustrates a block diagram depicting the condition monitoring device 102 and the portable device 104, in accordance with an implementation of the present subject matter.

[0026] The condition monitoring device 102 includes an energy source 202, a plurality of sensors 204-210, one or more processors 212 and a network interface 214, as depicted.

[0027] The energy source 202 can include batteries. In another example, the condition monitoring device 102 may be powered by an external power supply.

[0028] The plurality of sensors 204-210 are used to measure the parameters of the electrical machine 106. The plurality of sensors 204-210 include a magnetic field sensor 204, a vibration sensor 206, an acoustic sensor 208, and a temperature sensor 210. The magnetic field sensor 204 can measure the magnetic field related to the electrical machine 106. Similarly, the vibration sensor 206 can measure vibrations of the electrical machine 106, the acoustic sensor 208 can measure acoustic signals, such as sound waves, generated by the electrical machine 106, and the temperature sensor 210 can measure a temperature of the electrical machine 106.

[0029] The one or more processors 212, hereinafter referred to as processors 212, are configured to receive one or more measurements of the parameters of the electrical machine 106 from the plurality of sensors 204-210. Based on the received measurements, the processors 212 can determine the condition of the electrical machine 106.

[0030] The network interface 214 is configured for communicating the condition of the electrical machine 106 to the portable device 104. [0031] In an implementation, similar to the condition monitoring device 102, the portable device 104 also includes a second network interface 216, a second energy source 218, a second processor 220, and, a plurality of second sensors 222-228, as depicted.

[0032] Similar to the plurality of sensors 204-210, the plurality of second sensors 222-228 also include one or more of a magnetic field sensor 222, a vibration sensor 224, an acoustic sensor 226, and a temperature sensor 228.

[0033] The second processor 220 can receive measurements from the plurality of second sensors 222-228.

[0034] The plurality of sensors 204-210 of the condition monitoring device 102 and the plurality of second sensors 222-228 of the portable device 104 are used to measure one or more of the parameters of the electrical machine 106, independent of each other within the same accuracy range. This can be achieved by setting one or more appropriate threshold values for the measurement of the parameter by the plurality of sensors 204-210 and the plurality of second sensors 222-228.

[0035] The network interface 214 allows the condition monitoring device 102 to communicate the condition of the electrical machine 106 with the portable device 104 by wireless means.

[0036] In an implementation, the plurality of sensors 204-210 and the plurality of second sensors 222-228 are tuned such that the condition monitoring device 102 and the portable device 104 reliably produce the same bit pattern when they measure the parameter of the electrical machine 106. This can be achieved by setting one or more values related to the parameter such as relative signal strength and frequency change. Further, error correcting codes are used to ensure that the parameters are measured with the same accuracy.

[0037] The portable device 104 and the condition monitoring device 102 must authenticate each other to set up communication between them. For authentication, both the portable device 104 and the condition monitoring device 102 have to generate the same encryption key. For generating the same encryption key, the portable device 104 and the condition monitoring device 102 have to measure the same parameter of the electrical machine 106 about a same instance of time for the similar duration of time.

[0038] To measure the parameter for the same duration of time, the portable device 104 and the condition monitoring device 102 need to know when exactly they need to start measuring the parameter. For this purpose, a trigger event may be used. Hence, when the portable device 104 is brought into proximity with the condition monitoring device 102, a trigger event is generated at a first instance of time. This trigger event indicates to one sensor of sensors 204-210 and one sensor of second sensors 222-228 that they are to measure the parameter of the electrical machine 106. Thereafter, this parameter can be measured by the plurality of sensors 204- 210 and the plurality of second sensors 222-228.

[0039] In some examples, the trigger event may correspond to an occurrence of actuation of a push button on the condition monitoring device 102 and the portable device 104, receipt of a wireless signal by the condition monitoring device 102, a specific pattern parameter, and an increase in the parameter over a threshold, as will be explained in the subsequent paragraphs.

[0040] In an example, a physical button on the portable device 104 and a physical button on the condition monitoring device 102 may be simultaneously pressed by a person carrying the portable device 104 when the person is in proximity to the condition monitoring device 102, to initiate the measurement of the parameter of the electrical machine 106. Alternatively, the condition monitoring device 102 can receive a wireless signal from the portable device 104 to indicate that it should begin to measure the parameter of electrical machine 106. In another example, the portable device 104 is made to vibrate in proximity to the condition monitoring device 102, as the trigger event. [0041] After the trigger event, at least one sensor from the sensors

204-210 and at least one sensor from second sensors 222-228 begin to measure the parameter of the electrical machine 106. Subsequently, the condition monitoring device 102 and the portable device 104 respectively convert the measured parameter into a bit string. This is further illustrated using an example below.

[0042] In an exemplary embodiment, the bit string is generated from the measured parameter by using the signal amplitude or the residual signal amplitude after subtracting the expected base signal from the measured parameter signal. The residual signal (or "jitter") is typically unpredictable. Since both devices won't measure exactly the same signal at exactly the same time, thresholds may be used to enable generation of bit strings. In one such scheme all measurements with amplitude values below threshold value TLOW are considered low values (i.e. 0) and all measurements with amplitude values above threshold value THigh are considered as high values (i.e. 1 ), and any value in between is discarded. In another exemplary embodiment, the bit string is generated using error correcting code scheme. For example, each bit in the bit string is generated based on a predetermined number of bits measured. For example, x bits are measured, for some integer x, and the resulting bit is the bit that occurs at least y > x/2+1 times. The larger y, the better the mechanism can mask deviations between the measurements at the two devices. It is to be noted by a person skilled in the art that while two exemplary embodiments are illustrated for generating bit strings from the measurements of the measured parameter, other such techniques commonly known in the state of art may be used for the same.

[0043] A particular sequence of this bit string, called a bit pattern, is used by the condition monitoring device 102 and the portable device 104 to generate encryption keys to establish communication between them. The bit pattern may be a subset of the bit string. The sequence of the measured bit string identified by the condition monitoring device 102 is termed as a first bit pattern, while the sequence of the measured bit string identified by the portable device 104 is termed as second bit pattern. As an example, the sensors 204-210 of the condition monitoring device 102 and the second sensors 222-228 of the portable device 104 begin to measure the parameter of the electrical machine 106 after the trigger event. Subsequently, the condition monitoring device 102 may convert the measured parameter into a first bit string "000 001 001 001 1 1 1 1 10 1 1 1 Similarly, the portable device 104 may convert the measured parameter into a first bit string "000 001 001 001 1 1 1 1 10 1 1 1 ... ".

[0044] To authenticate each other, the condition monitoring device

102 and the portable device 104 need to generate similar encryption keys by processing the same sequence of bit pattern. In other words, the first bit pattern and the second bit pattern are to be the same.

[0045] As mentioned earlier, the first bit pattern and the second bit pattern are the subsets of the bit strings generated by the condition monitoring device 102 and the portable device 104, respectively. Therefore, to identify the start of the first bit pattern and the second bit pattern from the bit strings generated by the condition monitoring device 102 and the portable device 104, the start of the bit pattern is indicated using a predefined bit string called a preamble. This preamble comprises a certain sequence of bits that can be found in the bit pattern of the measured parameter of the electrical machine 106. The bit pattern to be processed begins after the preamble bit string.

[0046] In an example, the preamble may be a particular bit string, such as "001 001 001 ", which is stored in the condition monitoring device 102 and the portable device 104. After identifying the preamble, the condition monitoring device 102 and the portable device 104 need to measure the same number of bits for the first bit pattern and the second bit pattern to be the same. This number of bits may also be stored in the condition monitoring device 102 and the portable device 104. For example, the number of bits may be 1000. Hence, when the electrical machine 106 generates a parameter, the sensor of the condition monitoring device and the sensor of the portable device measure the parameter and convert it into a bit string respectively. Further, the condition monitoring device 102 and the portable device 104 identify the preamble "00 001 001 " in the bit string of the measured parameter to identify the start of the first bit pattern and the second bit pattern, respectively. Thereafter, the condition monitoring device 102 and the portable device 104 detect the number of bits in the bit string after the preamble to identify the end of the first bit pattern and the second bit pattern, respectively.

[0047] In an implementation, instead of the number of bits, the end of the bit pattern is identified based on a timer included in the condition monitoring device 102 and the portable device 104 respectively. The condition monitoring device 102 and the portable device 104 may identify the start of the bit pattern and continue to record the bit pattern for a period of time or a particular number of pulses.

[0048] In a further implementation, the end of the bit pattern is identified based on the preamble bit string.

[0049] The parameter of the electrical machine 106 has sufficient entropy or randomness to generate a unique cryptographic key. Further, the parameter is generated in real-time and can be measured by the portable device 104 only if it is in proximity with the electrical machine 106. The abovementioned reasons hinder security breaches, as a trespasser must be located close to the electrical machine 106 to measure the generated parameter. Additionally, a trespasser must record the parameter simultaneously as the portable device 104. Furthermore, the trespasser must know the beginning and the end of the particular bit pattern in the measured bit sequence, to be able to duplicate the encryption key. Since the trespasser cannot achieve all the steps necessary to duplicate the encryption key, the system achieves additional security against data breaches and data theft by trespassers. [0050] Additionally, in some examples, the identified bit pattern is combined with a bit string from a second parameter to generate an encryption key. The second parameter further adds to the entropy or randomness to the generated encryption key.

[0051] In an implementation, the second parameter is displayed, encoded or hardcoded into the condition monitoring device 102 such that it is directly accessible to a person in the proximity of the condition monitoring device 102. Hence, the portable device 104 can access the second parameter when the portable device 104 is in the proximity of the condition monitoring device 102. Thus, it is difficult for a trespasser to acquire the second parameter used to generate the encryption key without being in proximity to the condition monitoring device 102. Thus, the overall system provides security during authentication of the condition monitoring device 102 and the portable device 104.

[0052] In an implementation, the second parameter may be a static parameter, a dynamic parameter, a physical parameter, or a timestamp, as will be explained below.

[0053] In an example, the second parameter includes one or more static values which do not vary with time. These static values may be referred to as static second parameters. In an implementation, the static second parameter is an arbitrary predetermined information encoded on a Quick Response (QR) code which is attached to the condition monitoring device 102 or displayed on the screen of the condition monitoring device 102. In an implementation, the static second parameter is a Media Access Control address (MAC address or ID) of the condition monitoring device 102, or an Unique Identifier (UID) of the condition monitoring device 102 itself, which is accessible through a specification tag present on the body of the condition monitoring device 102.

[0054] In an embodiment, the second parameter changes with respect to one or more factors such as time and location. Such a second parameter may be referred to as a dynamic second parameter. In one such implementation, the second parameter is a noise associated with the measured parameter of the electrical machine 106.

[0055] In another implementation, a location of the electrical machine

106 is used as the dynamic second parameter. This location is available through a Global Positioning System (GPS) unit included in the condition monitoring device 102 or in form of a location data stored in the condition monitoring device 102. In an implementation, the portable device 104 utilizes one or more data received from the Global Positioning System (GPS) unit as a dynamic second parameter while generating the second encryption key. In another implementation, in case the condition monitoring device 102 does not include a Global Positioning System unit, the location at which the electrical machine 106 is to be commissioned, is stored in the condition monitoring device 102 before the condition monitoring device 102 and the electrical machine 106 is shipped from its place of manufacture. Accordingly, in this example, the portable device 104 utilizes the stored location data as a dynamic second parameter while generating the second encryption key.

[0056] In another embodiment, the second parameter is another physical parameter of the electrical machine 106. Such a second parameter may be referred to as a second physical parameter. Considering the electrical machine 106 is a motor, as an example, the physical second parameter could be for example, current, speed, or load of the motor. In this example, the physical second parameter of the motor can also be the ambient temperature about the motor or the magnetic field about the motor, as explained above. In case the magnetic field is selected to be the physical second parameter, the plurality of magnetic field sensor 204 of the condition monitoring device 102 and the magnetic field sensor 222 of the portable device 104 will use the value of the measured magnetic field of the motor as the physical second parameter.

[0057] Thus, the generation of the encryption key uses a shared bit string derived from the combination of the parameter of the electrical machine 106 and the high-entropy second parameter accessible to a person near the condition monitoring device 102 while the device is in the initial state. The encryption key may be generated by using combining the bit strings from the first parameter of the electrical machine 106 and the high- entropy second parameter using a plurality of techniques known in the art. For example XOR operation may be used for the same.

[0058] Hence, using the parameter of the electrical machine 106 as measured at a particular time instance can also prevent attacks from a person with physical access to the electrical machine 106 as the attacker must measure the parameter of the electrical machine 106 simultaneously along with the condition monitoring device 102 and the portable device 104. Further, the attacker must derive the exact same bit pattern from the measured parameter as compared to the condition monitoring device 102 and the portable device 104. This is not possible as the attacker must become aware of the trigger signal and identify the start and ending of the bit pattern, which cannot be accomplished by the attacker. Additionally, the attacker must extract the second parameter, which is unique, to generate the encryption key. Since the second parameter is available only in the proximity of the electrical machine 106, an attacker cannot duplicate the encryption key by eavesdropping from afar. Moreover, the attacker cannot easily swap out the key because the condition monitoring device 102 only executes the key generation mechanism when it is in the initial state. Thus, an attacker would have to first reset the condition monitoring device 102, which may be detected through some monitoring mechanism.

[0059] Thus, the condition monitoring device 102 combines the first bit pattern and the second parameter to generate the first encryption key; and the portable device 104 combines the second bit pattern with the second parameter to generate the second encryption key.

[0060] Further, predetermined data is stored on the condition monitoring device 102 and the portable device 104. The same predetermined data is stored on both the condition monitoring device 102 and the portable device 104 in order to compare and thus verify the encryption keys generated by the condition monitoring device 102 and the portable device 104. The portable device 104 encrypts the predetermined data using the second encryption key to generate another encrypted data.

[0061] For the authentication, the portable device 104 can send the predetermined data encrypted by the second encryption key as a handshake message to the condition monitoring device 102. The condition monitoring device 102, upon receiving the handshake message, decrypts the handshake message using the first encryption key and compares it with the predetermined data to verify the authenticity of the portable device 104. Similarly, for the authentication, the condition monitoring device 102 can send the predetermined data encrypted by the second encryption key as a handshake message to the portable device 104. The portable device 104, upon receiving the handshake message, compares the handshake message with the predetermined data encrypted by the second encryption key to verify the authenticity of the condition monitoring device 102. In case the authentication fails, the condition monitoring device 102 and the portable device 104 reject the encryption keys and proceed to measure the parameter of the electrical machine 106 again.

[0062] The abovementioned means of verifying the authenticity of the condition monitoring device 102 and the portable device 104 using the encryption keys and the predetermined data is referred to as an authentication of the handshake message. Further, in case the handshake message is authenticated, the condition monitoring device 102 accepts the encryption key and authenticates the portable device 104. Subsequently, the condition monitoring device 102 and the portable device 104 begin communicating securely through the network interfaces 214 and 216. Additionally, the state of the condition monitoring device 102 changes from the initial state to the second state.

[0063] Figs. 3 and 4 illustrate methods for establishing communication between a condition monitoring device 102 and a portable device 104 to communicate a condition of an electrical machine 106 with the portable device 104.

[0064] The order in which the methods 300 and 400 are described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the methods 300 and 400, or an alternative method. Furthermore, the methods 300 and 400 may be implemented by processor(s) or computing device(s) through any suitable hardware, non-transitory machine-readable instructions, or a combination thereof.

[0065] It may be understood that steps of the methods 300 and 400 may be performed by programmed computing devices and may be executed based on instructions stored in a non-transitory computer readable medium. Although the methods 300 and 400 may be implemented in a variety of systems, the methods 300 and 400 are described in relation to the industrial system 100, for ease of explanation.

[0066] Fig. 3 illustrates a method 300 for an initialization of the condition monitoring device of the example system, in accordance with principles of the present subject matter.

[0067] As depicted in step 302, at least one of an electrical and a mechanical parameter generated by an electrical machine is measured on a condition monitoring device and a portable device. The condition monitoring device can be, for example, a device comprising one or more sensors to measure the at least one of an electrical and a mechanical parameter generated by the electrical machine. The portable device can be, for example, a smart phone that is used by a person to collect information related to the condition of the electrical machine. Hereinafter, the at least one of an electrical parameter and a mechanical parameter of the electrical machine are collectively referred to as parameters of the electrical machine.

[0068] Further, the parameters of the electrical machine are converted into a bit string by the condition monitoring device. A preamble in the converted bit string is identified by the condition monitoring device to locate the start of the first bit pattern. Subsequently, the end of the first bit pattern is identified by the condition monitoring device after measuring a number of bits in the bit pattern.

[0069] As depicted in step 304, a first encryption key is generated by the condition monitoring device using the measurement data.

[0070] In an implementation, the first encryption key is generated by the condition monitoring device by combining the first bit pattern with a second parameter.

[0071] As depicted in step 306, a handshake message is received by the condition monitoring device from the portable device. The encrypted data which is received by the condition monitoring device is called the handshake message.

[0072] As depicted in step 308, the handshake message is authenticated by the condition monitoring device by using the first encryption key.

[0073] In an implementation, the authenticity of the condition monitoring device 102 and the portable device 104 may be verified by comparing the first encryption key with the second encryption key or by comparing the decrypted predetermined data with the stored predetermined data, as explained above. The abovementioned means of verifying the authentication is referred to as authentication of the handshake message.

[0074] As depicted at step 310, a secure communication is established by the condition monitoring device with the portable device through the network interfaces. Additionally, the state of the condition monitoring device shifts from an initial state to a second state.

[0075] Fig. 4 illustrates a method 400 for the initialization of the portable device of the example system, in accordance with principles of the present subject matter.

[0076] As depicted at step 402, the method 400 comprises measuring at least one of an electrical or a mechanical parameter of the electrical machine, on a condition monitoring device and a portable device. Hereinafter, the at least one of an electrical parameter and a mechanical parameter of the electrical machine are collectively referred to as parameters of the electrical machine.

[0077] Further, the measured parameter is converted by the portable device into a bit string. The start of a second bit pattern in the measured bit string is identified by the portable device by using a preamble. Subsequently, the end of the second bit pattern is identified by the portable device by measuring the bit string for a predefined number of bits.

[0078] As depicted at step 404, a second encryption key is generated by the portable device by using the measurement data. Specifically, the second bit pattern is combined with a second parameter by the portable device to generate the second encryption key.

[0079] As depicted at step 406, a handshake message is generated by the portable device by using the second encryption key to encrypt a predetermined data. This handshake message comprises a second encrypted data which was generated by the portable device by encrypting the predetermined data using the second encryption key.

[0080] As depicted at step 408, the handshake message is sent by the portable device to the condition monitoring device to establish communication.

[0081] Thus, the present subject matter enables a secure and reliable authentication method for establishing communication between portable devices and condition monitoring devices that measure data related to electrical machines in industrial systems. The encryption keys are generated from a particular bit pattern of a real-time parameter. Additionally, a second parameter present on or generated by the condition monitoring device is used to generate the encryption key. Hence, using two real-time parameters to generate an encryption key adds to the entropy and encryption strength of the system. This improves the overall security of the condition monitoring device and the industrial machines. [0082] Although the present subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter.

Claims

I/We claim:

A condition monitoring device of an electrical machine for communicating a condition of the electrical machine with a portable device, wherein the condition monitoring device is attached to a body of the electrical machine and the portable device is proximal to the electrical machine, and wherein the condition monitoring device and the portable device are respectively configured to measure at least one of an electrical parameter and a mechanical parameter of the electrical machine, the condition monitoring device comprising:

a. a plurality of sensors comprising at least one first sensor for measuring the at least one of an electrical parameter and a mechanical parameter of the electrical machine;

b. one or more processors configured to receive measurements from the plurality of sensors, and determine the condition of the electrical machine based on the received measurements; and

c. a network interface for communicating the condition of the electrical machine to the portable device; and

wherein the one or more processors are further configured to:

generate a first encryption key based on measurement data of the at least one of an electrical parameter and a mechanical parameter of the electrical machine from the at least one first sensor;

receive a handshake message via the network interface from the portable device; and

authenticate the handshake message from the portable device based on the generated first encryption key and establish communication with the portable device via the network interface.

The condition monitoring device as claimed in claim 1 , wherein the handshake message is encrypted by the portable device using a second encryption key generated by the portable device by measuring the at least one of an electrical parameter and a mechanical parameter of the electrical machine.

The condition monitoring device as claimed in claim 1 , wherein the one or more processors are further configured to obtain a second parameter and generate the first encryption key based on a combination of the second parameter and the at least one of an electrical parameter and a mechanical parameter; wherein the second parameter comprises one or more of a preconfigured random bit string stored in a memory of the condition monitoring device, a noise associated with the at least one of an electrical parameter and a mechanical parameter, another physical parameter associated with the electrical machine and measured by a sensor other than the at least one first sensor, a timestamp, and a location information of the electrical machine stored in the memory of the condition monitoring device, ,.

The condition monitoring device as claimed in claim 1 , wherein the at least one first sensor is configured to measure the at least one of an electrical parameter and a mechanical parameter based on a trigger event, wherein the trigger event corresponds to one or more of a push button being actuated on the condition monitoring device, receipt of a wireless signal by the condition monitoring device.

The condition monitoring device as claimed in claim 1 , wherein the at least one of an electrical parameter and a mechanical parameter is one of vibration, temperature, magnetic field, and acoustic signal.

The condition monitoring device as claimed in claim 1 , wherein, to generate the first encryption key from the at least one of an electrical parameter and a mechanical parameter, the one or more processors are configured to:

convert the at least one of an electrical parameter and a mechanical parameter into a bit string; identify a preamble in the bit string to identify a start of a first bit pattern for generation of the first encryption key; and

determine an end of the first bit pattern after a predefined number of bits from the start of the bit pattern.

A method for establishing communication between a condition monitoring device and a portable device to communicate a condition of an electrical machine with the portable device, wherein the condition monitoring device is attached to a body of the electrical machine and the portable device is proximal to the electrical machine, and wherein the condition monitoring device and the portable device are respectively configured to measure at least one of an electrical parameter and a mechanical parameter of the electrical machine at a first instance of time, the method comprising, at the condition monitoring device,:

generating a first encryption key based on measurement data of the at least one of an electrical parameter and a mechanical parameter of the electrical machine;

receiving a handshake message from the portable device, wherein the handshake message is encrypted by a second encryption key; and

authenticating the handshake message based on the generated first encryption key and establishing communication with the portable device via the network interface.

The method as claimed in claim 7, wherein the method further comprises, at the condition monitoring device, obtaining a second parameter and generating the first encryption key based on a combination of the second parameter and the at least one of an electrical parameter and a mechanical parameter; wherein the second parameter comprises one or more of a preconfigured random bit string stored in a memory of the condition monitoring device, a location information of the electrical machine stored in the memory of the condition monitoring device, a physical parameter associated with the electrical machine and measured by a sensor other than the at least one first sensor, a timestamp, and a noise associated with the at least one of an electrical parameter and a mechanical parameter. 9. The method as claimed in claim 7, wherein the method further comprises, at the portable device:

measuring the at least one of an electrical parameter and a mechanical parameter at the first instance of time; wherein at least one of the electrical parameter and a mechanical parameter is generated; wherein the at least one of the electrical parameter and a mechanical parameter comprises one of vibration, temperature, magnetic field, and acoustics;

generating the second encryption key based on measurement data of the at least one of an electrical parameter and a mechanical parameter;

encrypting a predetermined data using the second encryption key to generate the handshake message; and

sending the handshake message to the condition monitoring device. 10. The method as claimed in claim 7, wherein the first instance of time corresponds to an occurrence of one or more of a push button being actuated on the condition monitoring device, receipt of a wireless signal by the condition monitoring device, a specific pattern in the at least one of an electrical parameter and a mechanical parameter, and an increase in the at least one of an electrical parameter and a mechanical parameter over a threshold.