Printer Firmware Update via Device-Specific Key Decryption
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Solution Overview
Problem
Conventional methods for updating printer firmware face challenges in setting individual firmware for different devices within the same printer model, while also ensuring security by using a device-specific private key, which is not practical for public servers.
Innovation Solution
An information processing device acquires first encrypted firmware via an information communication device from a storage device, using a common key for encryption. The device generates a unique private and public key pair, decrypts the encrypted common key using the private key, and then decrypts the firmware using the common key for updating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a common key is prepared for each printer model to encrypt firmware, then firmware can be updated publicly, but individual firmware cannot be set for different devices within the same printer model
Solution Approach 1:
The patent segments the encryption approach by introducing device-specific key pairs for each individual device while maintaining a common key at the model level. This allows the firmware to be encrypted once with a common key and then selectively decrypted for specific devices, enabling both public update accessibility and individual device customization.
Solution Approach 2:
The patent introduces an intermediary decryption process where the commonly encrypted firmware is mediately decrypted using device-specific private keys. This intermediary step allows the same encrypted firmware to be adaptably applied to different devices within the same model, resolving the contradiction between public accessibility and individual customization.
2Reliability
If firmware is encrypted with a device-specific private key to enhance security, then only the intended device can decrypt firmware, but firmware cannot be uploaded to public servers
Solution Approach 1:
The patent segments the encryption layers into two levels: a common key layer for public server compatibility and a device-specific private key layer for security. The firmware is encrypted with the common key for public distribution, while each device holds the corresponding private key for secure decryption, allowing both public distribution and secure access.
Solution Approach 2:
The patent introduces a two-stage decryption process where the commonly encrypted firmware first serves as an intermediary that can be distributed publicly, and then the device-specific private key acts as the final intermediary to securely decrypt the firmware for the intended device only.
3Ease of operation
If a common key is used to encrypt firmware for public availability, then firmware distribution is simplified, but security performance is reduced
Solution Approach 1:
The patent segments the security architecture into distribution-level encryption using a common key and access-level security using device-specific private keys. This segmentation allows firmware to be easily distributed to public servers while maintaining strong security performance through the device-specific decryption requirement.
Solution Approach 2:
The patent creates a composite encryption system combining two different encryption approaches: common key encryption for distribution ease and device-specific private key encryption for security. This composite approach integrates the advantages of both methods, achieving both simplified distribution and enhanced security performance.
Data Source
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AI summary
To facilitate the use of FW for updating an information processing device while further enhancing security performance. An FW update system 100 includes a PC 130, a server 110 that stores first encrypted FW, which is FW encrypted with a common key, and a printer 150 that acquires the first encrypted FW via the PC 130. The printer 150 generates a pair of a device-specific private key and a device-specific public key, receives second encrypted FW including the first encrypted FW and an encrypted common key, which is the common key encrypted by using the device-specific public key via the PC 130, decrypts the encrypted common key by using the device-specific private key to acquire the common key, and then decrypts the first encrypted FW by using the common key, thereby acquiring the FW. By using this FW, the printer 150 then updates the FW of the printer 150.