Volatile Memory Data Overwriting for Secure Printing
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Solution Overview
Problem
In secure printing services, data remains in volatile memory even after deletion, making it difficult to completely erase confidential information, and existing methods require complex file system modifications.
Innovation Solution
A printing apparatus with a reception unit for external files, a volatile memory for storing data, and an overwriting unit that rewrites data with dummy data in the volatile memory's sectors, ensuring data security by making it difficult to restore deleted data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is deleted from the printing apparatus in secure printing service, then the file is removed from the file system, but the data remains in the volatile memory and can be restored
Solution Approach 1:
The patent applies preliminary action by overwriting data in volatile memory with dummy data immediately when a sector becomes invalid (i.e., when the file containing the data is deleted). This proactive measure ensures that confidential data is erased from memory before any potential recovery attempt can occur, resolving the contradiction between file deletion and data security.
Solution Approach 2:
The patent converts the harmful effect of data remaining in volatile memory into a benefit by systematically overwriting it with dummy data. The dummy data serves as a protective mechanism that transforms the potential security vulnerability into a security feature, making it impossible to restore deleted confidential information while maintaining normal file system operations.
2Reliability
If a file system driver is devised to delete data in RAM completely, then data security is improved, but the complexity of the system increases
Solution Approach 1:
The patent extracts the data security function from the complex file system driver by implementing a separate, dedicated overwriting unit that operates independently. This unit specifically targets volatile memory sectors and overwrites them with dummy data, separating the security-critical data erasure function from the general-purpose file system management, thereby reducing overall system complexity while maintaining security.
Solution Approach 2:
The patent introduces an intermediary overwriting unit that acts as a mediator between the file system and the volatile memory. This intermediary component handles the complex task of data overwriting without requiring modifications to the existing file system driver, thus maintaining simplicity in the file system while achieving complete data security through the intermediary's specialized function.
Data Source
AI summary
A printing apparatus receives a file transmitted from an external device, stores data included in the file in a volatile memory in a case where the external device is a server providing a secure printing service, and rewrites the data with dummy data, which is stored in a sector to a limit of the capacity in the volatile memory, in a case where the sector of the volatile memory storing the data is invalid. The volatile memory is a RAM and can be used as a RAMDISK.