Patent Description:
Automatic meter reading (AMR) systems and advanced meter infrastructure (AMI) systems, in the following commonly referred to as meter reading systems, are generally known in the art. Utility companies uses such meter reading systems to read and monitor customer meters remotely, typically using radio frequency (RF) communication. Meter reading systems increase the efficiency and accuracy of collecting readings and managing customer billing. AMR systems generally uses a mobile RF communication network for collecting meter readings and data, whereas AMI system uses a fixed RF communication network, such as a Low Power Wide Area Network (LPWAN). Especially in AMI systems there may be multiple intermediate collectors located throughout a larger geographic area, each collector in turn communicating with a head end system. Establishing such meter reading systems requires large investments in communication infrastructure and/or man power for the utilities. Further these meter reading systems does not provide a direct access to the meter reading data for the consumer, since data is send to the utility head end system and not directly to the consumer. Thus, the consumer needs to access data through a utility portal or utility connected application, with the result that the data available to the consumer are old e.g. relating to the consumption of the previous day.

As an alternative to the above mentioned dedicated meter reading infrastructures are general purpose Internet of Things (IoT) infrastructures, such as cellular infrastructures supporting LTE cat. M1 or LTE cat. Such IoT infrastructures are provide by telecommunication companies and requires payment of subscription fees and the use cellular communication technologies which is associated with license fees, whereby the cost associated with the use of these technologies raises significantly. Further, the power consumption in the utility meter for transmission of data via e.g. cellular communication network is very high, especially for battery operated meters this is problematic and reduces lifetime of the utility meter significantly. Thus, the data latency in such system data is normally very high since data is only transmitted a few times each day to save energy.

An important design criterion for meter reading systems is to protect the consumption data from unauthorized access whereby the privacy of the consumer would be compromised. Further, the integrity and authenticity of the consumption data send to the utility for billing purposes must be protected to avoid fraud e.g. by manipulation of the data. To ensure this, data security mechanisms is required to protect the consumption data during transmission from the utility meter to the head end system. This includes the use of data encryption and safe handling of data encryption keys, which complicates the process of granting consumer access directly to the utility meter and the risk of compromising data security in the process is high.

<CIT> discloses an apparatus for managing transfer of a utility usage meter reading from a utility meter to a utility provider. Information identifying a smart meter is received from a user device and a utility usage associated is received from the smart meter. The information received is stored when the information is successfully verified. Verifying comprises determining if there is an association between the smart meter and the user device.

<CIT> discloses a method for providing a mobile meter reader with an authorization that may be used to establish a secure session with a meter. The method includes issuing a request for authorization to access the meter from the mobile meter reader. If the mobile meter reader maintains sufficient rights, an authorization having an encoded digital signature is generated at a host computer system and provided to the mobile meter reader. Then the method formulates and transmits an authorization command to the meter having the encoded digital signature that was generated by the host computing system.

<CIT> discloses a method for polling of meter data measured by a plurality of utility measuring devices and transmitted over a wireless local area network. The method comprises encryption and decryption of the meter data and storing the data in an encrypted or decrypted format. Further, the method discloses transfer of encryption keys.

It is an object of the present invention to provide a simple, cost efficient and secure alternative to the known meter reading systems. In particular, it may be seen as an object of the present invention to provide a meter reading device and a method for meter reading which require installation of less dedicated meter reading infrastructure, reduces costs, minimizes energy consumption, provides consumer access to updated meter data and provides utility access to billing data without compromising data security and privacy.

Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a meter reading device comprising: a first communication interface for wireless communication with a utility meter; a second communication interface for wireless communication with a mobile phone; a microcontroller for controlling the communication interfaces and for processing data packets; and a key extraction module, the meter reading device being configured to: receive from the utility meter via the first communication interface, a data packet comprising a payload being at least partly encrypted by use of a data encryption key; and receive from the mobile phone via the second communication interface an access code comprising the data encryption key embedded in the access code, and extract from the access code the data encryption key by inputting the access code to the key extraction module; and decrypt the payload of the received data packet using the data encryption key extracted from the access code; and establish an encrypted connection to the mobile phone via the second communication interface and send at least a part of the decrypted payload to the mobile phone via the encrypted connection and send the received data packet including the encrypted payload to the mobile phone via the second communication interface.

The meter reading device according to all aspects of the invention is especially advantageous because it enables the use of an existing communication infrastructure provided by a mobile phone, such as a smart phone, for transferring consumption data to a consumer as well as to a utility company. The decrypted payload comprising consumption data is send from the meter reading device to the mobile phone via the encrypted connection. In the mobile phone the decrypted payload comprising consumption data may be displayed to the consumer. Further, the received data packet including the still encrypted payload comprising consumption data is additionally sent from the meter reading device to the mobile phone via the second communication interface and optionally also via the encrypted connection. The received data packet, which is still encrypted, may be forwarded by the mobile phone to a head end system of a utility company for billing purposes. Thus, the meter reading device provides a dual data stream where the first data stream provides the decrypted payload which may be accessed by the consumer being in possession of the mobile phone and the second data stream provides the still encrypted data packet whereby an end to end encrypted service between the utility meter and the head end system / utility company is established,.

The dual data stream is especially advantageous because it separates the data stream for the consumer from the data stream for billing purposes of the utility company. Hereby the high security end to end encryption for billing data is preserved while at the same time data for the consumer is made available to the consumer and protected by adequate data security mechanisms provided by the encrypted connection of the second communication interface. Thus, the only equipment that need to be installed to establish a secure and energy efficient dual channel meter reading system is the meter reading device.

Receiving the access code with an embedded data encryption key from the mobile phone has the advantage that the meter reading device does not need to be preconfigured with information about the meters to be read or the data encryption key required for decrypting the data. A further advantage is that the data encryption key is only extracted in the meter reading device. Thus, the data encryption key is not available in the mobile phone, this reduces the risk of compromising the data encryption key. The user may request the access code from the utility company by use of the mobile phone and then forward the access code to the meter reading device, where after the access code may be deleted from the mobile phone. It is not required that the mobile phone is able to extract the data encryption key from the access code, since the decryption of data is handled by the meter reading device. In other words, it may be preferred that the mobile phone is not able to extract the data encryption key from the access code.

The meter reading device may be a battery operated or mains powered device suitable for wall mounting in a home of a consumer. Since the meter reading device does not use cellular communication there is no need for cellular communication HW or an additional subscription of services from a cellular service provider which is often required for internet of things devices. Further, the power consumption of the meter reading device can be kept low, since it does not need to support cellular communication technologies. Thus, the meter reading device has very low manufacturing and operational costs, since it relies on the cellular communication channel provided by the mobile phone.

The first communication interface for wireless communication may be any communication interface suitable for wireless reading of utility meters such as wireless M-Bus, Zigbee, Zwave or a proprietary communication interface. Preferably the first communication interface is a radio (RF) communication interface. Optionally the first communication interface is a unidirectional communication interface, where data is transmitted from the utility meter, or alternatively the transfer of the data packet via the first communication interface is a unidirectional communication session.

The second communication interface is preferably a communication interface supported by mobile phones such as Bluetooth, Bluetooth LE, UWB or any other suitable wireless communication interface, preferably a radio (RF) communication interface. Preferably the second communication interface is a bidirectional communication interface.

The mobile phone is understood to be any mobile phone or smart phone or cell phone supporting data communication via a cellular communication network and via a second communication interface suitable for communication with the meter reading device. An alternative to a cell phone is a tablet or laptop including a cellular communication interface.

The data packet sent from the utility meter and received by the meter reading device may be any kind of data packet for wireless transmission of consumption data such as a wireless M-Bus data packet. The data packet comprises at least a payload for carrying consumption data. The consumption data carried in the payload may be consumption data registered by a utility meter such as a volume of water in case of a water meter, a volume of gas in case of a gas meter an amount of energy in case of a heat meter or electricity meter. The consumption data may also be other data related to the consumption such as flow rate, power, Voltage, current, temperature or alerts related to abnormal use or state of the utility such as leak, burst, tamper, over or under Voltage, power fail, battery state etc. The payload may be encrypted or at least partly encrypted by use of a data encryption key. Further the data packet may comprise a Message Authentication Code (MAC) such as a CMAC or a CBC MAC for verifying the authenticity of the packet or payload. The packet may also comprise a meter identification or device identification carried in an unencrypted header of the data packet or in the payload of the data packet.

The encrypted connection between the mobile phone and the meter reading device is understood to be a wireless connection for transfer of data protected by cryptographic methods such as encryption. In other word the encrypted connection is a cryptographically secure connection or a connection protected by cryptographic methods. The encrypted connection may be any connection suitable for protecting the privacy of the user by preventing unauthorized access to the data, and especially the payload, transmitted via the connection. The connection may optionally be based on the Transport Layer Security (TLS) protocol, Datagram Transport Layer Security (DTLS) protocol or the Bluetooth security as described in NIST publication SP <NUM>-<NUM> Rev. <NUM> (January <NUM>. <NUM>) and the Bluetooth specifications. Establishing an encrypted connection may include exchange of data encryption keys and / or session keys for protection and authentication of the data to be transferred via the connection. Establishing a connection may include a pairing of devices such as a pairing of Bluetooth devices.

Optionally the meter reading device comprises a meter reading device identification. The meter reading device identification may be stored in a memory of the meter reading device and / or printed on an external surface of the meter reading device and read from the meter reading device via one or more of the following optional communication interfaces: Near Field Communication (NFC), Ultra Wide Band (UWB) communication or optical scanning of a bar code or QR code or a simple number printed on the meter reading device. Optionally the meter reading device may be arranged to receive the meter reading device identification or a proof of knowing the meter reading device identification from the mobile phone via the second communication interface and only to establish an encrypted connection to a mobile phone from which the meter reading device identification or a proof of knowing the meter reading device identification of the meter reading device has been received. This has the advantage that only a mobile phone which has been in sufficiently close proximity of the meter reading device to read the meter reading device identification can establish a secure connection to the meter reading device whereby access to consumption data is achieved. Optionally more than one mobile phone may be connected to the meter reading device via an encrypted connection.

Optionally the meter reading device according to the first aspect may be arranged to automatically re-establish the encrypted connection to the mobile phone when the mobile phone re-enters communication range of the meter reading device after having been outside communication range. It is understood that the consumer may bring the mobile phone outside the coverage or communication range of the second communication interface. Thus it is preferable if the encrypted connection is automatically re-established when the mobile phone once again is within communication range of the meter reading device. Optionally the meter reading device may transfer data received during a period of no connection between the meter reading device and the mobile phone to the mobile phone upon re-establishment of the encrypted connection. This has the advantage that the meter reading device collects data required for establishing a complete consumption profile which may be presented to the consumer when the mobile phone re-enters communication range and which also may be forwarded to the utility company.

By sending the decrypted payload of the data packet to the mobile phone via the encrypted connection the consumption data is transferred to the mobile phone. The meter reading device may make a selection of the payload / consumption data to be transferred to the mobile phone. This has the advantage that only consumption data relevant to the consumer is made available in clear text. Since the received data packet including the encrypted payload is send to the mobile phone via the second communication interface all the consumption data may be made available to the utility company if the data packet is forwarded by the mobile phone to a head end system of the utility company. By sending the received data packet including the encrypted payload to the mobile phone is understood that the data packet and at least the elements of the data packet required for decrypting and decoding the data packet is send to the mobile phone. Optionally the meter reading device may be configured to send the received data packet including the encrypted payload to the mobile phone via the encrypted connection established via the second communication interface.

The meter reading device is understood to provide two data streams where the first data stream is provided by sending at least a part of the decrypted payload to the mobile phone via the encrypted connection and the second data stream is provided by sending the received data packet including the encrypted payload to the mobile phone via the second communication interface, where the first data of the first data stream is protected by the encrypted connection and the second data of the second data stream is protected by the end to end encryption provided by the encrypted payload of the data packet.

The key extraction module may be implemented in the microcontroller of the meter reading device or in a separate HW module or a combination of the two. The key extraction module is arranged to derive the data encryption key from the access code. The meter reading device is arranged to extract the data encryption from the access code by inputting at least the access code to the key extraction module. optionally the meter reading device according to the first aspect of the invention may further be arranged to extract the data encryption key from the access code by further inputting a meter identification to the key extraction module and to receive a data packet from the utility meter further comprising the meter identification in clear next. Including the meter identification in the extraction of the data encryption key has the advantage that the meter identification is directly connected to the access code. By comprising the meter identification in clear text is understood that the meter identification is included in the data packet in an unencrypted format, preferably in a header of the data packet.

Optionally the meter reading device according to the first aspect of the invention may further comprise a meter reading device identification and the data encryption key is extracted from the access code by further inputting the meter reading device identification to the key extraction module. Including the meter reading device identification in the extraction of the data encryption key has the advantage that the access code is only valid for one specific meter reading device whereby it is assured that only one specific meter reading device is authorized to extract the data encryption key based on a specific access code.

The access code comprising the data encryption key embedded in the access code is to be understood as the access code comprises the data encryption key or in other words an access code comprising an embedded data encryption key or in other words an access code wherein a data encryption key is embedded. The access code carries the data encryption key or at least carries information which in combination with the meter identification and/or meter reading device identification can be used for extracting the data encryption key by use of the key extraction module.

The meter reading device according to the first aspect of the invention may be arranged to receive an access code generated using a cryptographic method such that the data encryption key is embedded in the access code in an encrypted format and to extract the data encryption key from the access code using a cryptographic method such that the extracted data encryption key is in a decrypted format. In this context the access code is an access code wherein an encrypted data encryption key is embedded. Generating the access code using a cryptographic method has the advantage that the data encryption key is protected against unauthorized access. Further the meter reading device may additionally comprise an access code generation key which is additionally inputted to the key extraction module for extracting the data encryption key. It is to be understood that the access code generation key is also used for generating the access code.

The access code may be a string of characters or bytes such as preferably at least <NUM> characters / bytes or more preferably at least <NUM> characters / bytes or even more preferably at least <NUM> characters / bytes. The access code may even have a length of at least <NUM> or <NUM> characters / bytes.

The data encryption key and/or the access code generation keys may be symmetrical keys or alternatively asymmetrical keys. Symmetrical keys has the advantage of low cost and low energy consuming encryption and decryption operations. Optionally decrypting the payload of the data packet is done using the AES algorithm as specified in FIPS <NUM> (November <NUM>, <NUM>).

The meter reading device according to the first aspect of the invention may further comprise a storage such as a non-volatile memory area, and may further be arranged to store the received encrypted data packets and / or the decrypted payload in the storage and to send at least part of the stored data to the mobile phone when it is within communication range. Storing data has the advantage that the meter reading device may collect data required for establishing a complete consumption profile which may be transferred to the mobile phone at a later point in time. Further the meter reading device according to the first aspect of the invention may be arranged to scan for utility meters via the first communication interface and to store data packets received from one or more utility meters if, or optionally only if, the payload from the one or more utility meters is successfully decrypted by use of the data encryption key. Storing data packets from meters which can be successfully decoded has the advantage that the access code is determining which data packets are to be stored.

Further, the meter reading device according to the first aspect of the invention may be arranged to store the received encrypted data packets from one or more utility meters for which the payload cannot be successfully decrypted, and optionally forward these data packets to the mobile phone. This has the advantage that the meter reading device provides end to end encrypted data from utility meters within communication range without compromising the privacy of the consumers related to those utility meters. Optionally the meter reading device is arranged to send the received encrypted data packets from one or more utility meters for which the payload cannot be successfully decrypted to the mobile phone via the second communication interface and optionally using the encrypted connection.

Optionally the storage for storing at least the decrypted payload is a secured storage where the data is stored in an encrypted form or in an encrypted memory area. This has the advantage that the consumption data cannot be extracted from the meter reading device by an unauthorised person.

The optional elements and advantages described above for the meter reading device according to the first aspect of the invention does also apply to the second aspect of the invention as disclosed below.

In a second aspect of the invention is provided a method for reading a utility meter in a meter reading system comprising: a utility meter; a meter reading device; a mobile phone; and a head end system, where the meter reading device is arranged for wireless communication with the utility meter via a first communication interface and for wireless communication with the mobile phone via a second communication interface and where the mobile phone is arranged for communication with the head end system via cellular communication or Wi-Fi, the method comprising the steps of: sending from the head end system to the mobile phone an access code comprising an embedded data encryption key; sending the access code from the mobile phone to the meter reading device via the second communication interface; receiving in the meter reading device from the utility meter via the first communication interface, a data packet comprising a payload being at least partly encrypted by use of the data encryption key; extracting in the meter reading device the data encryption key from the access code; decrypting in the meter reading device the payload of the received data packet using the data encryption key extracted from the access code; establishing an encrypted connection between the meter reading device and the mobile phone via the second communication interface; sending at least a part of the decrypted payload from the meter reading device to the mobile phone via the encrypted connection; sending the data packet including the encrypted payload received in the meter reading device from the meter reading device to the mobile phone via the second communication interface; displaying on a display of the mobile phone the decrypted payload data received from the meter reading device; and sending from the mobile phone to the head end system via cellular communication or Wi-Fi the encrypted data packet received from the meter reading device.

The second aspect provides the same advantages as the first aspect of the invention and additionally in the second aspect the relation to the head end system is included. The head end system is to be under stood as one or more system, servers or web interfaces provide by the utility company or another service provider. The head ends system may be the receiver of consumption data for billing and analytics purposes and / or a server or portal for requesting access codes and verify that access codes are forwarded to users with the required authorisation to access data. The mobile phone receives the access code from the head end system and forwards it to the meter reading device, thus the mobile phone does not need to be in possession of the access code after it has been forwarded to the meter reading device. Thus, optionally the mobile phone deletes the access code from it memory after that it has been forwarded to the meter reading device. This has the advantage that the access code is not stored in the mobile phone which is connected to the internet and thus susceptible to hacking and other security breaches. Preferably the mobile phone communicates with the head end system via the internet which is accessed either via Wi-Fi, public cellular network i.e. cellular communication or another access technology.

Preferably the mobile phone is arranged to display at least a part of the decrypted payload data on a display of the mobile phone for providing information about the utility consumption to the consumer.

Optionally the method according to the second aspect of the invention further comprises the steps of: sending from the mobile phone to the head end system a request for an access code via a user application in the mobile phone; generating in the head end system the access code based on at least the data encryption key; and receiving in the mobile phone the access code from the head end system via a secondary channel. The request for the access code may be sent to the head end system either via Wi-Fi or via the cellular communication network. The secondary channel may be one of: an SMS, an E-mail, a phone call or a mail via postal service. Receiving the access code from the head end system via a secondary channel has the effect of increasing the security by a two factor authentication of the user. The phone number, email address or mail address of the user may be provided to the head end system by the utility company.

Optionally in the method according to the second aspect of the invention the data encryption key is extracted from the access code in the meter reading device by inputting the access code and at least a meter identification into a key extraction module and the data packet further comprises a meter identification in clear text.

Optionally in the method according to the second aspect of the invention the data encryption key is extracted from the access code in the meter reading device by inputting at least the access code and a meter reading device identification into a key extraction module, the method further comprising the steps of: reading with the mobile phone the meter reading device identification from the meter reading device either by an optical interface such as a bar code or a QR code or via NFC; including the meter reading device identification in the request for the access code generating in the head end system the access code based at least on the data encryption key and the meter reading device identification. The meter reading device identification is preferably not transmitted via the first communication interface. The QR code or bar code may be scanned with a camera of the mobile phone. Reading the meter reading device identification with an optical interface or NFC interface or alternatively a UWB interface has the advantage that such short distance communication technologies are not very susceptible to eavesdropping, thus including the meter reading device in the generation of the access code increases security and the protection from unauthorised access to the consumption data significantly.

Optionally in the method according to the second aspect of the invention the access code is generated using cryptographic methods such that the data encryption key is embedded in the access code in an encrypted format and the data encryption key is extracted from the access code using cryptographic methods such that the extracted data encryption key is in a decrypted format.

The meter reading device and method according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

In the following with reference to <FIG> is described an embodiment of a meter reading device <NUM>. The meter reading device <NUM> is installed in a private home at a consumer of a utility and is arranged to collect consumption data from a utility meter <NUM> installed in the home and arranged to measure the consumption of a utility such as water, gas, district heating energy or electricity. The user receives the meter reading device <NUM> from the utility company or another provider and installs it in the home. By use of a mobile phone <NUM> with a dedicated user application the consumer requests an access code <NUM> from the utility. The utility sends the access code <NUM> via a secondary channel <NUM>, such as an SMS to the mobile phone <NUM> which forwards it to the meter reading device <NUM> via a second communication interface <NUM>, such as a Bluetooth communication interface. The meter reading device <NUM> receives the access code <NUM> and extracts a data encryption key <NUM> from the access code. The meter reading device receives data packets <NUM> from the utility meter <NUM> via a first communication interface <NUM> for wireless communication, such as a wireless M-Bus (wM-Bus) communication interface. The data packets <NUM> carry consumption data <NUM> in an encrypted payload <NUM> of the data packet <NUM>. The data encryption key <NUM> is now used in the meter reading device <NUM> for decrypting data packets <NUM> received from the utility meter <NUM>. The Meter reading device <NUM> stores the received data packets <NUM> with an encrypted payload <NUM> as well as the decrypted payload <NUM>. When the mobile phone <NUM> is within communication range of the meter reading device <NUM>, the meter reading device will send the received data packets <NUM> with an encrypted payload <NUM> as well as the decrypted payload <NUM> to the mobile phone <NUM> via the second communication interface <NUM>. The mobile phone <NUM> will present the decrypted payload <NUM> to the consumer on a display <NUM> of the mobile phone and forward the received data packets <NUM> with an encrypted payload <NUM> for billing purposes to a head end system <NUM> controlled by the utility company. Thus, effectively one meter reading device establishes two data streams, a first data stream for consumer information and a second data stream for the utility company. The first data stream of the decrypted payload <NUM> is dedicated for informing the consumer of the energy consumption and the second data stream of end to end encrypted received data packets <NUM> with an encrypted payload <NUM> is dedicated for billing purposes of the utility company. Thus, a low cost secure meter reading system is provide by the meter reading device <NUM> in conjunction with the mobile phone <NUM> of the consumer and the head end system <NUM> of the utility company.

The meter reading device <NUM> of <FIG> is a battery operated or mains operated device for being wall mounted in a home of a consumer. The meter reading device <NUM> comprises a first communication interface <NUM> for wireless communication with a utility meter <NUM>. The first communication interface <NUM> supports wireless M-Bus communication but may alternatively support Zigbee, Zwave, Bluetooth LE, proprietary or other communication technologies suitable for communicating directly with the consumption meter. The meter reading device <NUM> further comprises a second communication interface <NUM> for wireless communication with a mobile phone <NUM>. The second communication interface <NUM> preferably supports a communication technology supported by commercial available mobile phones such as Bluetooth, Bluetooth LE, Wi-Fi or UWB but other communication technologies may be used. The meter reading device <NUM> has an integrated or external antenna (not shown) for each of the first and second communication interfaces or a shared antenna for the two communication interfaces. The meter reading device <NUM> comprises a microcontroller <NUM> for controlling the communication interfaces <NUM>, <NUM> and for handling and decoding the received data packets <NUM>. Further, the microcontroller <NUM> is arranged to control storage of data and forwarding of data to the mobile phone <NUM>. The meter reading device further comprises a key extraction module <NUM> for extracting the data encryption key from the access code. The key extraction module is <NUM> implemented in the microcontroller <NUM> but may alternatively be implemented in a separate HW component. The meter reading device further comprises a storage <NUM> for storing the received encrypted data packets <NUM> and the decrypted payload <NUM>. The storage <NUM> is a volatile or non-volatile memory such as RAM, EEPROM or FLASH memory. On the front of the meter reading device is arranged a QR code for reading a Meter reading device identification <NUM> by an optical interface such as a camera of the mobile phone <NUM>. The Meter reading device identification <NUM> is further stored in a memory of the meter reading device which is accessible to the microcontroller.

The meter reading device <NUM> receives data packets <NUM> from the utility meter via the first communication interface <NUM>. To reduce power consumption the meter reading device is arranged to use synchronized communication according to the wireless M-Bus standard EN13757-<NUM> when communicating with the utility meter <NUM>. The data packets <NUM> shown in <FIG> includes a header <NUM> with a meter identification <NUM> and payload <NUM> carrying the consumption data <NUM>. The payload is a at least partly encrypted payload <NUM> as described in EN13757-<NUM> and EN13757-<NUM>. When the data packet is received in the meter reading device the meter reading device decrypts the payload using a data encryption key <NUM> whereby the decrypted payload <NUM> becomes available in clear text. The decrypted payload <NUM> includes consumption data. Decryption is performed using an AES algorithm or another decryption algorithm <NUM> according to which the payload is encrypted as illustrated in <FIG>. Decryption of the payload is also described in EN13757-<NUM> and EN13757-<NUM>. The encryption algorithm may be a HW or SW implemented algorithm.

The meter reading device <NUM> is arranged to store the decrypted payload <NUM> or at least part of it in the storage <NUM>. The received data packet <NUM> including the encrypted payload <NUM> is also stored in the storage <NUM>. A part of the storage is a secure storage where at least the decrypted payload <NUM> is stored in a encrypted memory area whereby the decrypted payload is protected from unauthorised access e.g. by tampering with the meter reading device. The data encryption key <NUM> is also stored in the secure storage. The secure storage may be implemented by use of a commercial available secure memory chip.

The meter reading device <NUM> is arranged to receive the data encryption key <NUM> from the mobile phone <NUM> via the second communication interface <NUM>. The data encryption key <NUM> is embedded in an access code <NUM> transferred from the mobile phone to the meter reading device. The access code <NUM> comprises the data encryption key <NUM> in an encrypted format such that the data encryption key cannot be directly read from the access code. As illustrated in <FIG> the data encryption key is extracted from the access code by inputting the access code to the key extraction module <NUM> of the meter reading device <NUM>. The key extraction module uses the AES algorithm to extract the data encryption key <NUM> in a decrypted form from the access code <NUM>. To increase security one or more of the following optional elements may additionally be inputted to the key extraction module: a utility meter identification <NUM>, a Meter reading device identification <NUM>, a pre-shared secret <NUM>, a unique consumer identifier such as a telephone number, an e-mail address a social security number. The one or more optional elements are known to the meter reading device or transferred to the meter reading device via the mobile phone and known to the head end system which is arranged to generate the access code. The optional elements may be used as key material or initialisation vectors in the AES algorithm or be encrypted in the AES algorithm along with the data encryption key <NUM>. The use of the AES algorithm is described in details in FIPS <NUM> (November <NUM>, <NUM>), NIST Special Publication <NUM>-38A (<NUM>) and FIPS <NUM>-<NUM>.

The access code is generated in the head end system using the same algorithms and elements as described above with respect to the key extraction module. The access code is generated by inputting the data encryption key <NUM> to the AES algorithm so that it is encrypted by the AES algorithm. Further, the following optional elements may be used as key material or initialisation vectors in the AES algorithm or be encrypted in the AES algorithm along with the data encryption key <NUM>. The optional elements are one or more of: a utility meter identification <NUM>, a Meter reading device identification <NUM>, a pre-shared secret <NUM>, a unique consumer identifier such as a telephone number, an e-mail address or a social security number. The access code <NUM> is the output from the AES algorithm. As an alternative to the AES algorithm in the embodiments above any symmetric or asymmetric data encryption algorithm may be used such as DES, 3DES, IDEA, Serpent, Twofish RC4, RC5, RC6, RSA, ECC, DSA.

The meter reading device <NUM> establishes an encrypted connection <NUM> to the mobile phone <NUM> via the second communication interface <NUM>. The second communication interface is a Bluetooth or Bluetooth LE communication interface. The encrypted connection <NUM> is established using the data security mechanisms available in the Bluetooth standard. Establishing the encrypted connection and / or Bluetooth connection is initiated from the mobile phone <NUM> via a user application. When the Bluetooth connection has first been established the meter reading device <NUM> and the mobile phone <NUM> are configured to re-establish the connection automatically each time the mobile phone re-enters communication range with the meter reading device.

The meter reading device <NUM> will send the decrypted payload <NUM> and the received data packet <NUM> including the encrypted payload to the mobile phone <NUM> via the encrypted connection <NUM> established via the second communication interface <NUM>. When the mobile phone re-enters communication range of the meter reding device the meter reding device will forward data stored while outside communication range to the mobile phone.

More than one mobile phone <NUM> may connect to the meter reading device and establish an encrypted connection <NUM> to the mobile phone <NUM> via the second communication interface <NUM>.

When establishing the encrypted connection <NUM> the mobile phone <NUM> may read a meter reading device identification <NUM> from the meter reading device. The meter reading device identification <NUM> may be read from the meter reading device <NUM> via Near Field Communication (NFC), RFID, UWB or optical scanning of a bar code or QR or a simple number on the meter reading device <NUM> using the camera of the mobile phone <NUM>. To increase security the meter reading device <NUM> may only accept establishing a encrypted connection <NUM> to a mobile phone <NUM> which knows the meter reading device identification <NUM> provides a proof of this, e.g. by sending the meter reading device identification <NUM> to the meter reading device <NUM>.

In the following with reference to <FIG> and <FIG> is described an embodiment of a meter reading system and a method for reading a utility meter <NUM> in a meter reading system. The meter reading system comprises a utility meter <NUM> and a meter reading device <NUM> as described in the first embodiment, a mobile phone <NUM> and a head end system <NUM>.

The utility meter <NUM> may be any utility meter such as a water meter, a gas meter, a district heating meter or an electricity meter. The utility meter comprises a data encryption key <NUM> for encrypting the payload <NUM> of the transmitted data packets <NUM>. The data encryption key <NUM> may be programmed / configured in the utility meter <NUM> during manufacturing or when commissioning the utility meter. The data encryption key <NUM> is known to the head end system <NUM>. The utility meter transmits data packets according to the wM-Bus standard EN13757 which is very effective for meter reading and supports energy effective data transmission. Saving energy associated with data transmission is very relevant for battery operated meters such as water, gas and district heating meters.

The mobile phone <NUM> is preferably a mobile phone controlled by the consumer. The mobile phone <NUM> supports common communication interfaces for wireless communication such Bluetooth, Bluetooth LE, Wi-Fi and cellular communication. A special user application designed for interfacing the meter reading device <NUM> via Bluetooth, i.e. a Bluetooth connection via the second communication interface is installed on the mobile phone. The user application is further configured for displaying consumption data <NUM> on a display <NUM> of the mobile phone <NUM>. The user application is downloaded from the utility or another provider such as App Store of Google play store and installed on the mobile phone <NUM>. The user application may have an interface for requesting the access code <NUM> at the head end system <NUM> or at another interface of the utility company and it is designed for forwarding the access code <NUM> to the meter reading device <NUM> via the second communication interface <NUM>. The user application is designed for receiving data from the meter reading device and displaying decrypted consumption data <NUM> for the consumer / user of the mobile phone. Further the user application is designed for sending the encrypted data packet <NUM> received from the meter reading device <NUM> to the head end system <NUM> via the cellular communication interface or alternatively via Wi-Fi.

The head end system <NUM> is one or more systems or cloud solutions on one or more servers. The head end system <NUM> is responsible for handling of consumption data <NUM> after they have been delivered to the head end system, handling of encryption keys <NUM> and delegation of authorization to users and distribution of data encryption keys <NUM>. The head end system <NUM> may be separated in different systems / servers / solutions to enhance security. The head end system is controlled by the utility company or another service provider.

The method for reading a utility meter includes multiple steps, some of which are optional. In a step <NUM> the access code <NUM> is send to the mobile phone <NUM> from the head end system <NUM> or the utility company. The access code <NUM> comprises an embedded data encryption key <NUM> and is generated as described above in relation to the first embodiment. In an optional step 601a, a request for an access code <NUM> is send from the mobile phone <NUM> to the head end system <NUM> or utility company via the user application in the mobile phone <NUM>. The request for the access code <NUM> may be initiated by a user action. In an optional step 601b, the access code <NUM> is generated in the head end system <NUM> or at the utility company based on at least the data encryption key <NUM>. In an optional step 601c, the mobile phone <NUM> receives the access code <NUM> from the head end system <NUM> via a secondary channel <NUM>. The access code <NUM> may be sent via the internet and received in the mobile phone via the cellular network interface or via a Wi-Fi connection <NUM>, however, using one of the following technologies / methods for the secondary channel <NUM>, such as an SMS, an E-mail, a phone call (or a mail via postal service) will improve security. The secondary channel <NUM> may include a step or action of a user entering or copying the received access code into the user application.

In a further step <NUM> the access code <NUM> is send from the mobile phone <NUM> to the meter reading device <NUM> via the second communication interface <NUM> which is a Bluetooth communication interface, preferably Bluetooth LE. A Bluetooth connection is established between the mobile phone <NUM> and the meter reading device <NUM>. The access code <NUM> may be sent via an encrypted connection <NUM> established via the second communication interface <NUM> in step <NUM>.

In a further step <NUM> the meter reading device <NUM> receives a data packet <NUM> from a utility meter <NUM> via the first communication interface <NUM>. The data packet <NUM> comprises a payload <NUM> which is at least partly encrypted by use of the data encryption key <NUM>. The meter reading device <NUM> optionally stores the received encrypted data packet <NUM> in a storage <NUM> which is optionally a secure storage <NUM>.

In a further step <NUM> the meter reading device extracts the data encryption key <NUM> from the access code <NUM> by use of the key extraction module <NUM> as described in relation to the embodiment of the meter reading device above. The meter reading device <NUM> optionally stores the extracted data encryption key and / or the access code in a secure storage <NUM>.

Especially in step 601b the access code <NUM> may be generated using cryptographic methods such that the data encryption key <NUM> is embedded in the access code <NUM> in an encrypted format and the data encryption key <NUM> is extracted from the access code in step <NUM> using cryptographic methods such that the extracted data encryption key <NUM> is in a decrypted format. Several elements may be inputted to the algorithm generating the access code <NUM> and into the key extraction module <NUM> to increase security. Especially, inputting a Meter reading device identification <NUM> read from the meter reading device by a short range channel will increase security. A short range channel should be an interface supported by commercial available mobile phones such a Near Field Communication (NFC), RFID, UWB or optical scanning of a bar code or QR or a simple number on the meter reading device <NUM> using the camera of the mobile phone <NUM>. The user application in the mobile phone <NUM> can access these interfaces directly whereby the Meter reading device identification <NUM> is easily read by the mobile phone and transferred to the user application and further on the head end system <NUM>. The transfer of the Meter reading device identification <NUM> to the head end system <NUM> is done via a secured channel such as a TLS connection over Wi-Fi or cellular communication <NUM>.

In a further step <NUM> the meter reading device <NUM> decrypts the payload <NUM> of the received data packet <NUM> using the data encryption key <NUM> extracted from the access code <NUM> and optionally stores the decrypted payload <NUM> in a secure storage <NUM>.

In a further step <NUM> the meter reading device establishes an encrypted connection <NUM> between the meter reading device <NUM> and the mobile phone <NUM> via the second communication interface <NUM> which is a Bluetooth communication interface, preferably Bluetooth LE. The encrypted connection <NUM> is established using the data security mechanisms available in the Bluetooth standard. When the Bluetooth connection has first been established the meter reading device <NUM> and the mobile phone <NUM> are configured to re-establish the connection automatically each time the mobile phone <NUM> re-enters communication range with the meter reading device <NUM>.

In a further step <NUM> the meter reading device <NUM> sends at least a part of the decrypted payload <NUM> from the meter reading device <NUM> to the mobile phone <NUM> via the encrypted connection <NUM> established via the second communication interface in step <NUM>.

In a further step <NUM> the meter reading device <NUM> sends the data packet <NUM> including the encrypted payload <NUM>, <NUM> received in the meter reading device from the meter reading device to the mobile phone <NUM> via the second communication interface <NUM>. The data packet <NUM> including the encrypted payload <NUM> may be sent via the connection established din step <NUM> or the encrypted connection <NUM> in step <NUM>. It is to be understood that the connection in step <NUM> and <NUM> may be the one and same encrypted connection or may be two connections.

In a further step <NUM> the decrypted payload data received by the mobile phone <NUM> from the meter reading device <NUM> is displayed on a display <NUM> of the mobile phone. The decrypted payload <NUM> includes consumption data <NUM> and alerts suitable for consumer information. Thus, the consumer will be able to monitor the consumption and the state of the utility installation via the user application on the mobile phone <NUM>.

In a further step <NUM> the encrypted data packet <NUM> received from the meter reading device <NUM> is send from the mobile phone <NUM> to the head end system <NUM> via cellular communication or Wi-Fi <NUM>. The encrypted data packets <NUM> were encrypted by the utility meter <NUM> and are forwarded to the head end system <NUM> whereby an end to end encrypted data stream between the utility meter and the head end system is established.

The utility meter <NUM> may be any utility meter such as a water meter, a gas meter, a district heating meter.

The invention can be implemented by means of hardware, software, firmware or any combination of these. The invention or some of the features thereof can also be implemented as software running on one or more data processors and/or digital signal processors.

Claim 1:
A meter reading device (<NUM>) comprising:
- a first communication interface (<NUM>) for wireless communication with a utility meter (<NUM>);
- a second communication interface (<NUM>) for wireless communication with a mobile phone (<NUM>);
- a microcontroller (<NUM>) for controlling the communication interfaces (<NUM>, <NUM>) and for processing data packets (<NUM>); and
- a key extraction module (<NUM>),
the meter reading device (<NUM>) being configured to: receive from the utility meter (<NUM>) via the first communication interface (<NUM>), a data packet (<NUM>) comprising a payload (<NUM>) being at least partly encrypted (<NUM>) by use of a data encryption key (<NUM>); and receive from the mobile phone (<NUM>) via the second communication interface (<NUM>) an access code (<NUM>) comprising the data encryption key (<NUM>) embedded in the access code, and extract from the access code (<NUM>) the data encryption key (<NUM>) by inputting the access code to the key extraction module (<NUM>); and decrypt the payload (<NUM>) of the received data packet (<NUM>) using the data encryption key extracted from the access code; and establish an encrypted connection (<NUM>) to the mobile phone (<NUM>) via the second communication interface (<NUM>) and send at least a part of the decrypted payload (<NUM>) to the mobile phone via the encrypted connection (<NUM>) and send the received data packet (<NUM>) including the encrypted payload to the mobile phone (<NUM>) via the second communication interface (<NUM>).