Utility meter for metering a utility consumption and optimizing upstream communications and method for managing these communications

• US 9,664,531 B2
• Filed: 01/19/2012
• Issued: 05/30/2017
• Est. Priority Date: 02/02/2011
• Status: Active Grant

• Current Assignee: Nagravision SA (Kudelski SA)
• Original Assignee: Nagravision SA (Kudelski SA)
• Inventors: Le Buhan, Corinne, Nicolas, Christophe, Conus, Joel
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): Eustaquio, Cal
• Application Number:
  US13/983,286
• Publication Number:
  US 20130314249A1
• Time in Patent Office: 1,958 Days
• Field of Search: 34087002, 380281, 380282, 380284, 380285
• CPC Class Codes: G01D 4/002 Remote reading of utility meters
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 9/0618 Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms
• CPC Class Codes: H04L 9/30 Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04Q 2209/60 for transmitting utility meters data, i.e. transmission of data from the reader of the utility meter
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

A utility meter and method for metering consumption of at least one utility including: a metering unit, a communication unit for sending/receiving messages to/from a management center, a memory to store a unique identifier pertaining to the utility meter and a first key, an encryption unit for encrypting the utility consumption as a first cryptogram, a message generator for generating a utility message containing the first cryptogram, a key generator for generating a payload key to be used by the encryption unit for encrypting the utility consumption, a second cryptogram generated by the encryption unit by encrypting the payload key with the first key, the second cryptogram being intended to be included, by the message generator, at least once into the utility message to be sent to the remote management center.

Claims

1. A utility meter for metering at least one utility consumption comprising:

a metering circuit for metering at least one utility consumption value;

a communication circuit for sending messages to, and receiving messages from, a plurality of remote utility management centers assigned to the utility meter for processing said utility consumption value;

a memory to store a unique identifier pertaining to the utility meter and to store a plurality of first keys for encrypting control messages dedicated to the plurality of remote utility management center centers, wherein each of the plurality of first keys is specific to a single one of the plurality of remote utility management centers;

a key generator for generating a payload key shared with the remote utility management centers;

an encryption circuit for encrypting said utility consumption value as a first cryptogram using the payload key, and for generating a second cryptogram by encrypting said payload key using the first key associated with one of the remote utility management centers; and

a message generator for generating a shared payload message containing said first cryptogram to be sent to the plurality of remote utility management centers and a control message including the second cryptogram to be sent to the remote utility management center associated with the first key used to generate the second cryptogram.

2. The utility meter of claim 1, wherein each first key is a management center public key pertaining to said remote utility management center.

3. The utility meter of claim 1, wherein a secret key pertaining to the utility meter and an initialization value received within an initialization message by the communication circuit are stored in the memory, and further comprising a cryptographic circuit configured to generate at least one first key by taking said secret key as a first input and said initialization value as a second input, said first key being used as symmetric key.

4. The utility meter of claim 3, further comprising a decryption circuit for decrypting messages received by the communication circuit.

5. The utility meter of claim 4, wherein said memory further stores an initialization session key, said initialization message is encrypted with the initialization session key and the decryption circuit is able to decrypt said initialization message by using the initialization session key.

6. The utility meter of claim 4, wherein the initialization message comprises a signature for authentication of the initialization message, said utility meter further comprising an authentication circuit for verifying the authentication of the signature and allowing the loading of the initialization value into the cryptographic circuit in case of successful authentication.

7. A method to manage communications between a utility meter, configured for metering at least one utility consumption, and a plurality of remote utility management centers configured for processing utility consumptions, said communications being supervised by at least one supervision center, said method comprising the steps of:

requesting to the supervision center the allocation of a specific utility meter to at least two of the remote utility management centers by a request comprising at least the unique identifier of said utility meter;

in response, transmitting by the supervision center a different key data to each of the at least two remote utility management centers;

each key data being specific for a single one of the at least two remote utility management centers and being required for the decryption of control messages sent by the utility meter;

reading by the utility meter the utility consumption value;

generating by the utility meter a shared payload message comprising, as a first cryptogram, the encryption of the utility consumption value using a payload key derived from the control message, wherein the payload key is shared with the remote utility management centers;

sending by the utility meter the shared payload message to the remote utility management centers for processing by the remote utility management centers.

8. The method of claim 7, wherein the key data is a first key stored in the utility meter and used by the utility meter for encrypting said control message.

9. The method of claim 7, wherein the utility meter comprises a secret key, wherein said secret key is treated by the supervision center as confidential data, wherein the supervision center and the utility meter each comprises a cryptographic module integrating a function for generating a shared key by taking said secret key as a first input and an initialization value generated by the supervision center as a second input, wherein the key data is the shared key provided by the cryptographic module of the supervision center, and wherein the method further comprising the steps of:

generating the shared key by the supervision center using its cryptographic module;

transmitting said initialization value, from the supervision center to the utility meter, within an initialization message;

loading the initialization value and the secret key into the cryptographic module of the utility meter to obtain said shared key, the shared key being used for the encryption/decryption of the control messages according a symmetric encryption scheme.

10. The method of claim 9, wherein the transmitting step of said initialization value is performed through said remote utility management center which forwards the initialization message to the utility meter after having received it from the supervision center.

11. The method of claim 9, further comprising:

generating at the supervision center a signature of the initialization message and adding said signature to the initialization message for authentication purposes; and

verifying by the utility meter the authentication of said signature and allowing the loading of the initialization value into its cryptographic module in case of successful authentication.

12. The method of claim 9, further comprising:

adding by the supervision center a time stamp to the initialization message, said time stamp being defined by the supervision center on the basis of a current time; and

checking, by the utility meter, before loading the initialization value into its cryptographic module, the validity of the time stamp by comparing the time stamp with the current time and allowing this loading in case of successful validation.

13. The method of claim 12 wherein said current time is provided by a radio controlled signal.

14. The method of claim 8, further comprising the steps of:

generating, for each of the at least two remote utility management centers, a second cryptogram as a result of the encryption of said payload key; and

at least once including the second cryptogram into the control message before sending it to the remote utility management center for which the second cryptogram has been generated.

15. The method of claim 8, wherein said first key is a remote management center key pertaining to the remote utility management center for which the second cryptogram has been generated.