GB2484303A

GB2484303A - Device Identification Using Electrical Consumption Characteristics

Info

Publication number: GB2484303A
Application number: GB1016763.3A
Authority: GB
Inventors: Mahesh Sooriyabandara; Russell John Haines
Original assignee: Toshiba Research Europe Ltd
Current assignee: Toshiba Europe Ltd
Priority date: 2010-10-05
Filing date: 2010-10-05
Publication date: 2012-04-11
Anticipated expiration: 2030-10-05
Also published as: GB2484303B; GB201016763D0

Abstract

The identity of electrical devices is validated based on their consumption characteristics. A first characteristic of a device (101), corresponding to current electrical consumption characteristics associated with the device, is compared with a second characteristic of the device, corresponding to known electrical consumption characteristics associated with the device. The identity of the device is validated based on a result of the comparison. The device may have provided a preliminary identification previously, and the validation affirms this. The consumption characteristics may be measures by an ammeter (106a) and a voltmeter (106b). The characteristics may be consumption fingerprints, and may be produced using a function. The consumption characteristics may be determined using an electrical metric template, which may specify that the characteristics should be sampled over a period of time. The second characteristics may be obtained from a database.

Description

I

Device Identification The present invention relates to characterisation of electrical/electronic devices. More specifically, the present invention relates to determining energy characteristics associated with electrical/electronic devices to uniquely identifying such devices.

Electrical and electronic devices are becoming ever more complex and powerful: Such devices are able to perform many tasks, and provide a means for helping manage both business and personal life. In particular, electronic devices are now the primary means for communications in both business and personal environments. As such, electronic devices are generally arranged to communicate over one or more networks such as the Internet or a cellular mobile phone network. However, when communicating over these networks there is a risk of fraudulent infiltration into the electronic communications between devices. Hence, security of electronic devices, particularly for network communications, is of utmost importance. This problem is becoming more and more challenging with an increasing trend towards machine-to-machine communications where systems of networks that interconnect different devices provide new services to devices, or even administer, regulate or manage them.

There are many ways of reducing the likelihood of fraudulent intervention into electronic communications occurring. For example, encryption of data as well as requiring security keys and passwords are common techniques. For example, authentication of devices, where IDs/passwords is commonly used. However, none of these commonly used techniques are foolproof, for example, there is always a risk that hackers will find a way to overcome such techniques. There is therefore an ongoing need to improve the security of electronic communications.

A verifiable unique device identity allows establishment of the trustworthiness of devices. This facilitates secure device provisioning.

One common technique used is to identify a device using a vendor ID, a model number, a production number and other interoperability information. The device has to manage these attributes so that the combined attributes are unique and will not be valid on another device. Hence, artificially assigned numbers/attributes used in this ID management model which is easy to replicate and misuse.

Another technique used to improve such electronic security is known as "TCP/IP fingerprinting". This technique aims to identify a host operating system by monitoring the behaviour of the IP stack associated with the IP address of the host operating system communicating over the Internet (usually OSI layer 4 fields).

While IP fingerprinting provides an additional layer of protection it is possible for hackers to mimic the behaviour of a particular IP stack. Furthermore, IP fingerprinting is only of use when communications are taking place over the Internet over TCP/IP.

Hence, IP fingerprinting is a limited form of security.

Blueprinting is a technique used for determining a model and firmware version of a Bluetooth device. This information can then be used as a security operation for determining if a device communicating using Bluetooth is the expected model and has an expected firmware version.

RF fingerprinting is a security technique used for RF communications. In RF fingerprinting an RF signal received from a device is analysed and a "fingerprint" of the variation in RF characteristics of the device is determined. During later communications with the device similar analysis and determination is carried out and then this predetermined RF "fingerprint" is compared with the newly determined RF "fingerprint" to determine that they are the same. If the "fingerprints" have a certain level of similarity it is determined that the same device is communicating. However, RF fingerprinting only provides additional security to devices using RF communications, and is therefore somewhat limited in this regard.

There are various other RF based security procedures. For example, other known RF-based techniques involve sending out predetermined signals and analysing their response to such known query signals. In a similar way to described above, with respect to RF fingerprinting it is possible to determine if the device communicating is the device it claims to be.

None of the techniques discussed above provide an additional level of security, which is universally applicable to different devices and different types of communication.

However, there have been some attempts to provide more universally applicable device specific security procedures, as set-out below.

One known method involves analysing a "local" clock signal along with a clock signal provided in accordance with the "universal" network time. A skew between the local clock signal and universal clock signal is then determined. The skew can then be used to provide a detailed picture as to the location of the device. From the device location it can be determined whether the device is the device it says it is.

While this clock skew based procedure is more universally applicable, it suffers from the problem that it relies on devices being fixed because the determination of whether the device is the device it states it is relies on the local clock signal, i.e. a fixed location device. Consequently, this technique may not be applicable to many electronic devices

that are portable.

There is, therefore, a need for a security procedure, which can be applied to more types of electronic devices and more types of communications protocols.

Embodiments of the present invention aim to at least partly overcome some of the aforementioned problems.

In accordance with a first aspect of the present invention there is provided a method for validating the identity of electrical devices, comprising: comparing a first characterisation of a device, corresponding to current electrical consumption characteristics associated with the device, with a second characterisation of the device, corresponding to known electrical consumption characteristics associated with the device; and validating the identity of the device based on a result of the comparison.

The method may further comprise characterising the device based on the current electrical consumption characteristics to obtain the first characterisation of the device.

The electrical consumption fingerprint may be produced using a function, which is arranged to convert the electrical consumption characteristics of the device into an electrical consumption fingerprint format.

The method may further comprise determinftig the electrical consumption characteristics associated with the device.

The current electrical consumption characteristics may be determined using an electrical metric template which defines the parameters used in the determination.

The electrical metric template may be selected in accordance with known characteristics of the device.

The method may further comprise obtaining the second characterisation of the device from a database.

The device may be successfully validated if there is a sufficient correlation between the first and second characteristics of the device.

There may be sufficient correlation between the first and second characteristics of the device when the first and second characteristics of the device are identical.

In accordance with a second aspect of the present invention there is provided an apparatus for validating the identity of electrical devices, comprising a processor arranged to: compare a first characterisation of a device, corresponding to current electrical consumption characteristics associated with the device, with a second characterisation of the device, corresponding to known electrical consumption characteristics associated with the device; and validate the identity of the device based on a result of the comparison.

The processor may be further arranged to characterise the device based on the current electrical consumption characteristics to obtain the first characterisation of the device.

The first and second characterisations of the device may be electrical consumption fingerprints derived from the electrical consumption characteristics associated with the device, the electrical consumption fingerprints providing a representation of the electrical consumption characteristics associated with the device.

The processor may be arranged to produce the electrical consumption fingerprint using a function, the function being arranged to convert the electrical consumption characteristics of the device into an electrical consumption fingerprint format.

The electrical consumption fingerprint may be unique.

The processor may be further arranged to determine the current electrical consumption characteristics associated with the device.

The processor may be arranged to determine the current electrical consumption characteristics using an electrical consumption metric template which defines the parameters used in the determination.

The electrical consumption metric template may specify that electrical consumption characteristics of the device should be sampled over a period of time.

The processor may be arranged to select the electrical consumption metric template in accordance with known characteristics of the device.

The processor may be arranged to obtain the second characterisation of the device from a database.

The second characterisation of the device may be produced when registering the device.

The processor may be arranged to successfully validate the device if there is a sufficient correlation between the first and second characteristics of the device.

The processor may be arranged to determine that there is sufficient correlation between the first and second characteristics of the device when the first and second characteristics of the device are identical.

In accordance with another aspect of the present invention there is provided a carrier medium carrying computer readable code for controlling a suitable computer to carry out the method discussed above.

In accordance with another aspect of the present invention there is provided a carrier medium carrying computer readable code for configuring a suitable computer as the apparatus discussed above.

Embodiments of the present invention aim to provide a security procedure for determining the identity of a device. The technique of the present invention shalt hereinafter be referred to as "energy fingerprinting". In general, energy fingerprinting involves determining energy characteristics of a device. More particularly, the variation in energy consumption over time is determined in order to record a unique energy fingerprint associated with the device. This unique energy fingerprint can then be used for various procedures such as checking whether a device taking part in a communication session is the device it claims to be.

Embodiments of the present invention provide a means for uniquely identifying devices based on their energy usage characteristics. These energy usage characteristics could be collected by passive or active means, could be power specific (i.e. relate to characteristics such as voltage and/or current), be device specific (i.e. relate to resistance, capacitance and/or inductance), or could be transient attributes (i.e. relate to impulse or frequency characteristics). In some embodiments of the invention, the device characteristics are determined locally with respect to the device under test, or remotely, for example at a server related to the device.

Embodiments of the present invention involve sampling devices power consumption patterns over time.

Embodiments of the present invention can be used in identity management andlor security applications. For example, embodiments of the present invention are applicable to smart grid applications, in addition to M2M applications. While some embodiments of the present invention relate to providing a primary or sole security procedure, other embodiments of the invention relate to providing a secondary or back-up security procedure.

Embodiments of the present invention shall now by described with reference to the accompanying drawings, in which: Figure 1 illustrates a system in accordance with a first embodiment of the present invention; and Figure 2 illustrates the energy fingerprint determination device of Figure 1.

Throughout this specification like reference numerals refer to like parts.

A first embodiment of the invention shall now be described with reference to Figure 1, which shows a system utilising an embodiment of the present invention.

A first device 101 attempts to set up a communication with a second device 102 via a network 103. In this embodiment of the invention the first device 101 is a computer.

The computer may be operated by a user or could be operating in a machine to machine communication. The computer 101 attempts to access information stored on the second device 102, which is a server. In this embodiment of the invention the network 103 is the Internet. It will be appreciated that the first and second devices could be any form of electrical or electronic device, while the network could be any communications network.

In order to access the information on the server 102 the computer 101 has to provide various security codes or passwords, which are sent through the network 103 to the server 102. If the computer is being operated by a user, the user may have to provide such security codes or passwords. These security provisions are provided in order to check that the user is who the user claims to be. However, in order to provide an additional level of security the server 102 also validates the identity of the computer 101 by determining the computer's energy fingerprint (EFP).

The server 102 checks the EFP because there is a risk that the security details have in some way been fraudulently obtained. That is, an unauthorised device is trying to access the server using a fake identity. The server 102 is then able to determine if these details are from the computer associated with the account. Hence, use of the EFP can provide an additional level of security to a network communication.

After the server 102 receives an information access request from the computer 101, the server 102 firstly sends an energy fingerprint request to the computer 101. The computer 101 then obtains a current EFP from an energy fingerprint determination device 106, which is connected between the computer 101 and the power supply 104 of the computer 102. The computer 101 is then able to relay the determined EFP onto the server 102.

The server also obtains a predetermined, or stored, EFP associated with the computer 101 from an energy fingerprint management system 105.

The energy fingerprint management system 105 is a system arranged to collect and store EFPs that can be used to verify the identify of electronic devices. In particular, in this case, computer 101 has a unique identification number, which is supplied upon manufacture. However, for old devices this number can be provided when registering the device with the energy fingerprint management system 105. Upon registration with the energy fingerprint management system 105 an energy characterisation of the device is carried out, from this energy characterisation an EFP is created. The process of obtaining an EFP is discussed in more detail below with reference to Figure 2. The EFP is then stored in the database of the energy fingerprint management system 105 and associated with the corresponding identification number.

In the case of this first embodiment of the invention, a request for the EFP corresponding to the identification number of the computer 101 is made by the server 102. The energy fingerprint management server 105 then sends the stored EFP back to the server 102.

The server 102 is then able to perform a comparison of the EFP sent by the computer 101 and the EFP associated with the device stored in the energy fingerprint management server 105. If there is a sufficient correlation between the EFPs then it is determined that the computer is the device it claims to be, and communications can continue. If the correlation is not sufficiently close then the communication may be terminated. In such a case it may be necessary for the computer 101 to pass through further security in order to allow the computer 101 to obtain information from the server 102.

The operation and functionality of the energy fingerprint determination device 106 shall now be explained with reference to Figure 2, which shows the energy fingerprint determination device 106 connected between the power supply 104 and the computer 101. As it is the computer that is being characterised it shall also be referred to as the device under test (DUT).

An Energy Metric Template (EMT) or Profile (EMP) is used to collect the information about the electrical/electronic characteristics of the device. In this embodiment of the invention the EMT is a template that provides a system for obtaining the voltage and current characteristics of the device over time. However, it will be appreciated that in different embodiments and for different devices alternative electrical characteristics could be collected as part of the EMT. For example, active power, reactive power collected during transient and/or steady state could also be used.

As mentioned above, in this embodiment of the invention the EFP of the DUT is determined by the energy fingerprint determination device 106 using the EMT which 16 specifies that a variation in the current drawn by the device and the variation in the voltage across the device will be determined over time. In particular, the energy fingerprint determination device 106 includes an ammeter 106a to monitor the current, a voltmeter 106b to monitor the voltage, and a processor 106c arranged to, amongst other functionalities, take periodic samples of the current and voltage from the ammeter and voltmeter respectively. The processor 106c takes a predetermined number of samples, each sample separated by a pre-determined period.

Once a sufficient number of samples have been taken the processor 106c is able to convert the variation in current and voltage over time into a unique representation of this information in the form of the EFP.

The EFP is generated using a suitable algorithm, referred to as the Energy Finger-Print Generator Function (EFPGF). The complexity and uniqueness of the EFP will depend upon the complexity of the EFPGF. Different EFPGFs may use different techniques to create the EFP, each technique having a varying level of accuracy. For example, the final EFP could be described using a hash value or a vector. However, the complexity of the EFP will depend upon a balance of the need for a unique EFP compared to the processing requirements associated with the device creating the EFP.

Once the EFP is generated it can then be gent from the energy fingerprint determination device 106 to the computer 101 and then onto the server 102, as discussed above with respect to Figure 1.

A first embodiment of the invention has now been described in detail. Various alternative embodiments of the invention are discussed below. Those features of the above embodiment of the invention equally applicable to the embodiments described below shall not be repeated. Furthermore, it will be appreciated that each of the embodiments described herein can be combined with one another, where appropriate, provided the embodiments stay within the scope of the appended claims.

It will be appreciated that new electronic devices can be characterised for their electrical properties and their EFP at the point of manufacture. Those devices that have already been manufactured and not characterised can then be characterised when they first use a system utilising an energy fingerprinting security procedure.

Alternatively, characterisation could be carried out upon registration with a management system.

While a device, such as the server, making the request to the database for the EFP is described as being the device that compares the fingerprints, it will be appreciated that in alternative embodiments the management system could perform this functionality. In particular, the server 102 or computer 101 could send the energy fingerprint to the management system 105, and the management system could then compare the received EFP with the stored EFP and provide a response indicating that the EFP is or is not sufficiently close to the stored EFP. This procedure increases security because the stored EFP is never sent out, and this makes it harder for anyone to fraudulently obtain or copy the EFP.

In addition, it will be appreciated that while the first embodiment of the invention described above discloses that the energy fingerprint determination device 106 performs the functions of: determining the energy characteristics of the device; determining a suitable function for producing an energy fingerprint from the energy characteristics; producing the energy fingerprint; and comparing the energy fingerprint with a predetermined or known energy fingerprint, each of these functions could be performed by a separate device.

Furthermore, both the EMT and the EFPGF used to create the EFP could be selected on a case-by-case basis. For example, if the EFPGF functionality could be performed by a central system rather than by a each separate device, and as such it may be necessary to select an EFPGF dependent upon the device being characterised. The same applies to the selection of the EMT.

While the above embodiment only describes storing the EFP in the database, it may also be possible to store the electrical characteristics that are determined, and the EFPGF used to generate the EFP. However, how much information is stored will depend upon parameters such as the storage allowancefrequirements of the database.

Further, it may be required that the central system periodically monitors and registers from time to time the electrical characteristics and the associated EFP to accommodate for any physical changes happens in a device over time.

In the first embodiment of the invention described above, the processor 106c communicates through the DUT or computer 101 in order to relay the EFP. However, in alternative embodiments of the invention the energy fingerprint determination device 106 could be provided with the capabilities to communicate over the network 103.

While the DUT has primarily been described as a computer, it will be appreciated that the present invention applies to any suitable electronic device.

While the energy fingerprint determination device 106 has been described as a stand-alone device, in other embodiments of the invention the energy fingerprint determination device 106 is incorporated into a device capable of using the security procedure of the present invention. Furthermore, in yet further alternate embodiments of the invention the energy fingerprint determination device 106 could be positioned across the network from the DUT and characterise the OUT remotely.

While the above embodiments describe a globally accessible database for checking the correct EFP for a device, it will be appreciated that one or more non-globally accessible databases could be provided. For example, a particular communications supplier or organisation could provide a database of registered devices, which is then used by other registered devices when communicating with one another. In such a case, the EFP for the database could be collected when setting up a first communication or when registering with the server. Hence, the database could be built in the server system; a separate database or management system is, therefore, not necessarily required.

The previously described embodiments of the invention involve use of a device specific number to identify the device. However, it will be appreciated that such a specific serial number may not be required. The database can instead store one or more of information relating to the make, model, serial number, or IP address associated with the device. When a request is sent to the database for the stored EFP one or more of these identifiers could be sent with the request.

While the first embodiment of the invention describes the device energy characterisation as being a secondary security procedure, it will be appreciated that this procedure could be the primary anda'or only security procedure provided.

The present invention need not only apply to security within communications between devices, but could equally apply to device management applications.

The present invention can be implemented in dedicated hardware, using a programmable digital controller suitably programmed, or using a cprnbination of hardware and software.

Alternatively, the present invention can be implemented by software or programmable computing apparatus. This includes any computer, or such like. The code for each process in the methods according to the invention may be modular, or may be arranged in an alternative way to perform the same function.

While the term "energy fingerprint" has been used throughout this application to refer to the result of the electrical consumption determination, it will be appreciated that alternative terminology such as "electrical consumption fingerprint", or "electrical consumption ID" could be used.

Each of the function alities of the invention can in whole, or in part, be implemented by the combination of a processor and associated memory, or by a standard computer system. Furthermore, functions described herein is being implemented as part of a single unit may be provided separately, communicatively coupled across a network.

The present invention can encompass a carrier medium carrying machine readable instructions or computer code for controlling a programmable controller, computer or number of computers as the apparatus of the invention. The carrier medium can comprise any storage medium such as a floppy disk, CD ROM, DVD ROM, hard disk, magnetic tape, or programmable memory device, or a transient medium such as an electrical, optical, microwave, RF, electromagnetic, magnetic or acoustical signal. An example of such a signal is an encoded signal carrying a computer code over a communications network, e.g. a Tcp/IP signal carrying computer code over an IP network such as the Internet, or an intranet, or a local area network.

It is appreciated that various features of the invention which are, for clarity, described in the contexts of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable subcombination.

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the invention is defined only by the claims.

Claims

CLAIMS: 1. A method for validating the identity of electrical devices, comprising: comparing a first characterisation of a device, corresponding to current electrical consumption characteristics associated with the device, with a second characterisation of the device, corresponding to known electrical consumption characteristics associated with the device; and validating the identity of the device based on a result of the comparison.
2. The method according to claim 1, further comprising: characterising the device based on the current electrical consumption characteristics to obtain the first characterisation of the device.
3. The method according to claim I or 2, wherein: the first and second characterisations of the device are electrical consumption fingerprints derived from the electrical consumption characteristics associated with the device, the electrical consumption fingerprints providing a representation of the electrical consumption characteristics associated with the device.
4. The method according to claim 3, wherein the electrical consumption fingerprint is produced using a function, which is arranged to convert the electrical consumption characteristics of the device into an electrical consumption fingerprint format.
5. The method according to claim 3 or 4, wherein the electrical consumption fingerprint is unique.
6. The method according to any preceding claim, further comprising determining the electrical consumption characteristics associated with the device.
7. The method according to claim 6, wherein the current electrical consumption characteristics are determined using an electrical metric template which defines the parameters used in the determination.
8. The method according to claim 7, wherein the electrical consumption metric template specifies that electrical consumption characteristics of the device should be sampled over a period of time.
9. The method according to any one of claims 7 orB, wherein the electrical metric template is selected in accordance with known characteristics of the device.
10. The method according to any preceding claim, further comprising: obtaining the second characterisation of the device from a database.
11. The method according to any preceding claim, wherein the second characterisation of the device is produced when registering the device.
12. The method according to any preceding claim, wherein the device is successfully validated if there is a sufficient correlation between the first and second characteristics of the device.
13. The method according to claim 12, wherein there is sufficient correlation between the first and second characteristics of the device when the first and second characteristics of the device are identical.
14. An apparatus for validating the identity of electrical devices, comprising a processor arranged to: compare a first characterisation of a device, corresponding to current electrical consumption characteristics associated with the device, with a second characterisation of the device, corresponding to known electrical consumption characteristics associated with the device; and validate the identity of the device based on a result of the comparison.
15. The apparatus according to claim 14, wherein the processor is further arranged to characterise the device based on the current electrical consumption characteristics to obtain the first characterisation of the device.
16. The apparatus according to claim 14 or 15, wherein: the first and second characterisations of th& device are electrical consumption fingerprints derived from the electrical consumption characteristics associated with the device, the electrical consumption fingerprints providing a representation of the electrical consumption characteristics associated with the device.
17. The apparatus according to claim 16, wherein the processor is arranged to produce the electrical consumption fingerprint using a function, the function being arranged to convert the electrical consumption characteristics of the device into an electrical consumption fingerprint format.
18. The apparatus according to claim 16 or 17, wherein the electrical consumption fingerprint is unique.
19. The apparatus according to any one of claims 14 to 18, wherein the processor is further arranged to determine the current electrical consumption characteristics associated with the device.
20. The apparatus according to claim 19, wherein the processor is arranged to determine the current electrical consumption characteristics using an electrical consumption metric template which defines the parameters used in the determination.
21. The apparatus according to claim 20, wherein the electrical consumption metric template specifies that electrical consumption characteristics of the device should be sampled over a period of time.
22. The apparatus according to any one of claims 20 or 21, wherein the processor is arranged to select the electrical consumption metric template in accordance with known characteristics of the device.
23. The apparatus according to any one of claims 14 to 22, wherein the processor is arranged to obtain the second characterisation of the device from a database.
24. The apparatus according to any one of claims 14 to 23, wherein the second characterisation of the device is produced when registering the device.
25. The apparatus according to any one of clains 14 to 24, wherein the processor is arranged to successfully validate the device if there is a sufficient correlation between the first and second characteristics of the device.
26. The apparatus according to claim 25, wherein the processor is arranged to determine that there is sufficient correlation between the first and second characteristics of the device when the first and second characteristics of the device are identical.
27. A carrier medium carrying computer readable code for controlling a suitable computer to carry out the method of any one of claims I to 13.
28. A carrier medium carrying computer readable code for configuring a suitable computer as the apparatus of any of claims 14 to 26.