Field Module Authentication Using Cryptographic Key Verification
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Solution Overview
Problem
Current methods for authenticating electronic modules in automation technology lack the ability to reliably verify the authenticity of modules, posing a security risk, especially in environments where incorrect modules could lead to hazardous conditions.
Innovation Solution
A method utilizing asymmetric cryptography, specifically RSA or elliptic curve-based key pairs, to verify the authenticity of electronic modules by checking their public and private keys through a challenge-response process, ensuring only trusted modules are integrated into the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual inspection is used to verify module authenticity, then the process is simple and quick, but it cannot reliably detect manipulated or non-authentic modules
Solution Approach 1:
The patent applies preliminary action by pre-configuring electronic modules with unique cryptographic identifiers (public keys) during manufacturing. These identifiers are embedded in the module's memory before deployment, enabling automatic authenticity verification when modules are integrated into the automation system, eliminating the need for manual visual inspection.
Solution Approach 2:
The patent replaces the mechanical/visual inspection system with an electronic cryptographic verification system. Instead of manually examining module physical characteristics, the system automatically reads and verifies the cryptographic identifiers stored in module memory using digital communication protocols, significantly improving reliability while maintaining simplicity.
2Reliability
If cryptographic verification is implemented, then module authenticity is reliably verified, but the integration process becomes more complex
Solution Approach 1:
The patent applies self-service by designing the cryptographic verification process to be automatically performed by the automation system itself during module integration. The system reads the public key from the module, checks it against stored reference data, and either accepts or rejects the module without requiring manual cryptographic operations or complex user intervention.
Solution Approach 2:
The patent implements partial verification by focusing only on the essential cryptographic identifier (public key) rather than performing complete cryptographic handshakes or multiple verification steps. This selective approach provides sufficient security for module authentication while keeping the integration process simple and quick.
3Reliability
If cryptographic key pairs are stored in module memory, then authenticity can be verified, but security risks arise if modules are compromised
Solution Approach 1:
The patent extracts only the public key (cryptographic identifier) from the complete cryptographic key pair and stores it in the module memory. The corresponding private key remains securely stored in the central system's memory, separated from the module. This separation ensures that even if a module is compromised, attackers cannot obtain the private key needed to forge authentication or decrypt communications.
Solution Approach 2:
The patent uses the public key as an intermediary element that enables authentication without exposing sensitive private keys. The public key acts as a safe mediator that can be freely distributed to modules while the private key remains protected in the central system, allowing verification of module authenticity without creating security vulnerabilities.
Data Source
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AI summary
The invention relates to a method for verifying the authenticity of electronic modules (Mk) of a modularly constructed field device (FG) for automation technology, wherein each electronic module (Mk with k = 1, 2, ... n) of the field device (FG) is assigned a suitable key pair (Pk, pk with k = 1, 2....n) that confirms the identity of the electronic module (Mk), wherein each key pair (Pk, pk) consists of a public key (Pk) and a private key (pk), and wherein the public keys (Pk) of the suitable key pairs (Pk, pk) are stored in a list (MTL), wherein the list (MTL) is assigned to the field device (FG) or to a unit (U) communicating with the field device (FG).wherein the procedure comprises the following steps: - when an electronic module (Mk) is replaced or added, the field device (FG) or the unit (U) communicating with the field device (FG) verifies: - whether the replaced or added electronic module (Mk) has a key pair (Pk, pk), and - whether the public key (Pk) of the replaced or added electronic module is listed in the list (MTL) of public keys (Pk), - whether the electronic module (Mk) possesses the correct private key (pk), - communication or interaction between the replaced or added electronic module (Mk) and the field device (FG) or another electronic module relating to the functionality of the field device is permitted if the verification is completed successfully.