Smart Meter Response Signing for Command Integrity Verification

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Solution Overview

Problem

Existing security measures in smart meter management systems, such as those defined by COSEM specifications, are inadequate in preventing alterations of command identifiers, leading to misinterpretation of smart meter operations by management devices.

Innovation Solution

A method and system that includes generating a signature on a set of data comprising output attributes and metadata associated with the smart meter response, including a copy of the operation descriptor, to ensure the integrity of the operation performed, and verifying this signature upon receipt to detect alterations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If COSEM data protection object is used to sign output attributes and metadata, then response integrity is improved, but command alteration detection capability deteriorates

Engineering Contradiction:
Improveresponse integrityVSAvoidcommand alteration undetected
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the protection mechanism into two distinct parts: (1) signing only the output attributes without the operation descriptor, and (2) separately verifying the operation descriptor against the signed hash. This segmentation allows the system to maintain response integrity through signing while simultaneously enabling command alteration detection by comparing the original operation descriptor with the one embedded in the signed data.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary verification step where the management device extracts the operation descriptor from the signed response data, computes a hash of this descriptor, and compares it with the operation descriptor contained in the signed hash. This intermediary comparison mechanism acts as a mediator that detects command alterations without compromising the original signing process for output attribute integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If operation descriptor is included in signed metadata, then command alteration detection is improved, but data transmission volume increases

Engineering Contradiction:
Improvecommand alteration detectionVSAvoiddata transmission volume
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent employs copying by embedding a copy of the operation descriptor within the signed hash structure in the response. This copied descriptor enables verification of command integrity without requiring transmission of additional redundant data, as the same operation descriptor is efficiently reused within the signed data structure itself.

Inventive Principle:
Principle #26Copying

3Reliability

If comprehensive signing of all response data is implemented, then security is improved, but processing complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the operation descriptor from the complete response data structure and performs signing only on the essential output attributes combined with the operation descriptor in a condensed format. This extraction approach reduces the volume of data requiring complex processing while maintaining security by ensuring the critical operation descriptor is still protected and verifiable.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4679772A1Method and system for securely responding to a command from a smart meter
Publication Date: 2026.01.14 SAGEMCOM ENERGY & TELECOM SAS
  • EP4679772A1 patent drawingFigure 1~2
  • EP4679772A1 patent drawingFigure 3~4
  • EP4679772A1 patent drawingFigure 5~6

AI summary

To transmit (705) a response to a received command that included a descriptor (OP_DESC) of an operation to be performed, a smart meter retrieves output attributes (ATT_O) and metadata (MD_O) associated with the response, to be provided as the results of executing the received command. The smart meter includes (702) in the metadata (MD_O) associated with the response the descriptor (OP_DESC) of the operation to be performed that was provided in the received command, and performs (703) a security measure that generates a signature on a set of data formed by the output attributes (ATT_O) and the metadata (MD_O) associated with the response.