Ephemeral-Key Public Key Authentication Without Digital Signatures

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Solution Overview

Problem

Existing public key authentication protocols in access control systems face inefficiencies due to high computational resource consumption and potential non-repudiation issues, which can lead to battery drain and security vulnerabilities.

Innovation Solution

Establish a communication session using ephemeral keys, computing a shared session key based on a combination of public and private keys, and exchanging messages securely without generating digital signatures, thereby avoiding non-repudiation and reducing computational overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If digital signatures are generated using public key authentication protocols, then authentication security is improved, but computational resource consumption increases and battery drain occurs

Engineering Contradiction:
Improveauthentication securityVSAvoidcomputational resource consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the digital signature generation step from the authentication protocol, keeping only the essential key exchange and verification mechanisms. This eliminates the computationally expensive signature operations while maintaining the core authentication functionality through ephemeral key-based mutual authentication.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses ephemeral keys that are generated temporarily for each authentication session and then discarded. These short-lived keys provide sufficient security for the authentication purpose without requiring the heavy computational overhead of digital signatures, and their temporary nature ensures security even if compromised.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If digital signatures are generated for authentication, then non-repudiation is achieved, but security vulnerabilities arise from key compromise impersonation

Engineering Contradiction:
Improvenon-repudiationVSAvoidkey compromise impersonation attacks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs dynamic ephemeral keys that change with each authentication session rather than static keys. This dynamic approach ensures that even if one session's keys are compromised, past and future sessions remain secure, preventing key compromise impersonation attacks while maintaining authentication integrity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary key exchange and establishment of ephemeral keys before any authentication operations. This preliminary setup creates a secure foundation that prevents impersonation attacks by ensuring both parties have verified credentials before exchanging sensitive information.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional public key authentication protocols are used, then authentication is achieved, but system efficiency decreases and resource consumption increases

Engineering Contradiction:
Improveauthentication functionalityVSAvoidsystem efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent removes the computationally intensive digital signature generation step from the authentication protocol, retaining only the essential key exchange and verification mechanisms. This extraction maintains authentication functionality while dramatically improving system efficiency by eliminating unnecessary computational overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs only the necessary minimum actions for authentication - key exchange and verification - without the excessive action of generating digital signatures. This partial approach achieves the required authentication functionality with optimal resource utilization and improved system efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4344127B1Non-repudiation-free public key authentication protocols
Publication Date: 2026.01.28 ASSA ABLOY AB
  • EP4344127B1 patent drawingFigure 1
  • EP4344127B1 patent drawingFigure 2
  • EP4344127B1 patent drawingFigure 3

AI summary

Methods and systems for securely communicating with an access control system are provided. The methods and systems establish, between first and second devices, a communication session based on a plurality of ephemeral keys. The methods and systems compute, by the first device, a shared session key as a function of a second public key of the second device and a sum of a first private key of the first device and a first ephemeral key of the plurality of ephemeral keys; and compute, by the second device, the shared session key as a function of a second private key of the second device and a sum of a first public key of the first device and a second ephemeral key of the plurality of ephemeral keys. The methods and systems exchange one or more messages securely between the first device and the second device using the shared session key.