Industrial Controller Key Pair Protection for Program Content
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Solution Overview
Problem
Industrial automation environments face challenges in protecting controller program content from unauthorized viewing, editing, and execution, particularly when transmitted over unsecured networks or used in potentially hostile environments, as existing solutions lack device-specific cryptographic protection and are vulnerable to global key weaknesses.
Innovation Solution
A unique public/private encryption key pair is generated for each industrial controller, with the private key stored in secure storage and the public key used to encrypt controller program content, ensuring only the intended device can decrypt and execute the content, utilizing a certificate authority for authentication and additional security through multiple encryption keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single global encryption key is used to protect controller program content, then ease of implementation is improved, but security is worsened due to vulnerability to global key weaknesses and unauthorized access
Solution Approach 1:
The patent divides the single global encryption key into multiple device-specific key pairs (public key and private key). Each controller receives encrypted content with a unique public key, and only the corresponding private key stored in secure element 104 can decrypt it. This segmentation eliminates the security vulnerability of a single global key while maintaining implementation feasibility through automated key distribution.
Solution Approach 2:
The patent introduces secure element 104 as an intermediary component that generates and protects the private key. The secure element acts as a trusted mediator that never exposes the private key to external systems, enabling secure decryption while preventing unauthorized access. This intermediary mechanism resolves the contradiction by providing strong security without requiring complex key management infrastructure.
2Reliability
If device-specific encryption key pairs are generated for each controller, then security is improved, but device complexity is worsened due to key generation and management requirements
Solution Approach 1:
The patent implements self-service by enabling secure element 104 to automatically generate its own private key and corresponding public key without external intervention. The secure element autonomously manages the key lifecycle including generation, storage, and usage, eliminating the need for complex external key management infrastructure and reducing device complexity despite enhanced security.
Solution Approach 2:
The patent uses the public key as a copyable, distributable artifact that can be freely transmitted to content encryption systems. Unlike the private key which must remain secret, the public key can be copied and distributed without security risks, simplifying the key management process while maintaining strong security through the asymmetric cryptographic relationship.
3Reliability
If controller program content is encrypted with device-specific public keys, then unauthorized execution is prevented, but ease of operation is worsened due to decryption requirements
Solution Approach 1:
The patent applies preliminary action by pre-distributing the public key to the content encryption system before content encryption occurs. This allows the content to be pre-encrypted with the correct device-specific public key, so that when the encrypted content reaches the controller, decryption can proceed automatically without requiring real-time key exchange or complex authentication procedures, thus maintaining ease of operation.
Solution Approach 2:
The public key serves as a copyable credential that can be freely distributed to multiple systems without compromising security. This copying capability simplifies the encryption workflow because the public key can be replicated and stored in content encryption systems, enabling automatic decryption at the controller without requiring complex operational procedures or manual key management during execution.
Data Source
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AI summary
Techniques to facilitate protecting control data used in an industrial automation environment are disclosed herein. In at least one implementation, an encryption key pair is generated for an industrial controller, wherein the encryption key pair comprises a public key and a private key. The private key is stored within a secure storage system of the industrial controller. Controller program content is then encrypted using the public key to generate encrypted controller content. The encrypted controller content is then provided to the industrial controller, and the industrial controller is configured to decrypt the encrypted controller content using the private key and execute the controller program content.