Programmable Logic Controller Encryption Filter Authentication
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Solution Overview
Problem
Conventional programmable logic controllers lack encryption of data used within the system, leading to inadequate confidentiality, and existing solutions require additional peripheral devices for encryption, increasing system size and complexity.
Innovation Solution
A programmable logic controller with an authentication function unit, authentication-information storage, and an encryption filter that performs user authentication and encrypts data using multiple encryption patterns, ensuring secure data access and storage by encrypting data with a different pattern upon unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If data is stored in the device without encryption, then ease of operation is improved, but confidentiality of information deteriorates
Solution Approach 1:
An encryption filter is introduced as an intermediary component between the external device and the storage device. The encryption filter automatically performs encryption processing on data before it is written to the device, and decryption processing on data before it is read from the device. This mediator handles the complex encryption/decryption operations transparently, maintaining ease of operation while ensuring data confidentiality through automated cryptographic processing.
2Loss of information
If an external peripheral device with encryption function is added, then confidentiality of information is improved, but device complexity increases
Solution Approach 1:
The encryption function is merged with the existing programmable logic controller system by integrating an encryption filter and authentication function unit into the controller's CPU. This consolidation eliminates the need for separate external encryption peripheral devices, reducing system complexity while maintaining strong data confidentiality through built-in cryptographic capabilities.
Solution Approach 2:
The programmable logic controller is enhanced with multi-functionality by incorporating both authentication and encryption capabilities within its CPU. The controller now serves multiple functions: traditional control operations, user authentication verification, and automated encryption/decryption processing. This universal approach eliminates the need for dedicated external encryption devices while providing comprehensive security.
3Loss of information
If authentication is required for data access, then confidentiality of information is improved, but ease of operation deteriorates
Solution Approach 1:
User authentication is performed as a preliminary action before any data reading or writing operations. The authentication function unit verifies user credentials in advance and establishes authentication status. Subsequently, the encryption filter uses this authentication information to automatically determine whether to encrypt or decrypt data, or to permit/unpermit access. This preliminary authentication approach ensures confidentiality while maintaining ease of operation for authorized users through automated subsequent processing.
Data Source
AI summary
A programmable logic controller includes a device that stores therein data, an authentication-information storage unit that stores therein authentication information, an authentication function unit that performs a user authentication based on the authentication information, and an encryption filter that has a plurality of encryption patterns. When writing of data to the device is requested, the authentication function unit performs the user authentication. When the user authentication is successful, the encryption filter performs the encryption processing to the data with the encryption pattern set in advance by the user to write the data to the device, and when the user authentication fails, the encryption filter performs the encryption processing to the data with one of the encryption patterns that is different from the encryption pattern set in advance by the user to write the data to the device.