Dynamic Message Authentication Code Length Negotiation

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Solution Overview

Problem

Wireless communication networks face challenges in maintaining consistent message authentication code (MAC) lengths between user devices and base stations, leading to authentication failures and communication disruptions due to differences in MAC lengths supported by various devices.

Innovation Solution

The system dynamically determines and adjusts the MAC length for integrity protection based on the capabilities of user devices, allowing base stations to inform or configure the desired MAC length, ensuring consistent MAC usage for both user plane and control plane messages, thereby preventing authentication failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a longer MAC length (e.g., 64, 128, or 256 bits) is used to improve security, then the likelihood of MAC collision decreases and security increases, but device compatibility issues arise due to different devices supporting different MAC lengths

Engineering Contradiction:
ImprovesecurityVSAvoiddevice compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic MAC length selection where the base station and user device negotiate and adapt the MAC length based on device capabilities. The system transitions from static MAC length to dynamic adjustment, allowing shorter MACs for legacy devices and longer MACs for advanced devices that support them, thereby resolving the contradiction between security and compatibility

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of MAC length from a fixed value to a variable that can be adjusted based on device capabilities. By introducing capability indication messages and negotiating MAC length parameters during connection establishment, the system allows different MAC lengths (32, 64, 128, or 256 bits) to be used with different devices, resolving the compatibility issue while maintaining security where possible

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a shorter default MAC length is used to ensure compatibility across all devices, then device compatibility is maintained, but security is degraded

Engineering Contradiction:
Improvedevice compatibilityVSAvoidsecurity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by allowing different MAC lengths to be used with different devices based on their capabilities. Instead of using a uniform short MAC length for all devices, the system tailors the MAC length to each device's security capabilities, using longer MACs with devices that support them and shorter MACs with legacy devices, thereby maintaining compatibility while improving security where possible

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a universal system that can handle multiple MAC lengths (32, 64, 128, 256 bits) through a single negotiation mechanism. The base station and user device exchange capability information and agree on an appropriate MAC length, making the system universally compatible across different device types while allowing each device to use the optimal MAC length for its capabilities

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If MAC length capability negotiation is implemented to resolve compatibility issues, then device compatibility improves, but system complexity increases due to additional signaling and configuration

Engineering Contradiction:
Improvedevice compatibilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by having the user device indicate its MAC length capabilities in advance during the connection establishment phase, before actual data transmission begins. The base station receives this capability indication and determines the appropriate MAC length beforehand, avoiding the need for complex runtime negotiations and reducing signaling overhead during data transmission

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3903444B1Integrity protection with message authentication codes having different lengths
Publication Date: 2024.11.27 GOOGLE LLC
  • EP3903444B1 patent drawingFigure 1
  • EP3903444B1 patent drawingFigure 2A
  • EP3903444B1 patent drawingFigure 2B

AI summary

A method in a user device that supports a plurality of message authentication code (MAC) lengths for integrity protection of wireless communications includes receiving, from a base station, a first message including an information element (1002), determining, based on the information element, that a first MAC length of the plurality of MAC lengths is to be used for integrity protection (1004) and, thereafter, generating a second message including a MAC having the first MAC length (1006). The method also includes transmitting the second message to the base station (1008).