Memory Card Encryption Key Management via Block-Level Access Control

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Solution Overview

Problem

Existing content encryption methods fail to prevent unauthorized use of encrypted content, as decryption keys can be leaked and shared, allowing unauthorized access and reproduction of protected content.

Innovation Solution

An information processing system and method that unifies the management of encryption keys by using a memory card with a protected area, where access is restricted based on block-level access rights, and a content usage managing server determines the storage block for the encryption key, ensuring only authorized access and usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If content encryption is implemented to prevent unauthorized use, then content security is improved, but decryption keys can still be leaked and shared leading to unauthorized access

Engineering Contradiction:

Improvecontent securityVSAvoidkey leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The storage medium is divided into a protected area and a general area. The protected area stores decryption keys with restricted access, while the general area stores content. This segmentation prevents key leakage by isolating keys from general access, resolving the contradiction between providing decryption capability and preventing unauthorized key distribution.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different access rights are assigned to different areas of the storage medium. The protected area has strict access control allowing only reading of decryption keys, while the general area allows content access. This local differentiation of access permissions ensures that even if the storage medium is accessed, decryption keys remain protected, addressing the key leakage problem while maintaining content usability.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If decryption keys are provided to authorized users, then content accessibility is improved, but unauthorized users can also obtain and use the keys

Engineering Contradiction:

Improvecontent accessibilityVSAvoidusage control

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A data processing unit acts as an intermediary between the protected area and the general area. It verifies access rights before allowing reading of decryption keys from the protected area, and controls writing operations. This intermediary layer ensures that only authorized operations can access keys, maintaining both accessibility for authorized users and control against unauthorized use.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a protected area is created in the storage medium to store decryption keys, then key security is improved, but device complexity increases

Engineering Contradiction:

Improvekey securityVSAvoidstorage structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

4Measurement precision

If access control is implemented at the block level in the protected area, then access precision is improved, but processing complexity increases

Engineering Contradiction:

Improveaccess control precisionVSAvoidprocessing logic

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2854060B1Information processing device, information processing system, information processing method, and program

Publication Date: 2019.07.10 SONY GROUP CORP

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AI summary

The present disclosure realizes a structure that can unify the management of the storage block for the encryption key to be used in decrypting encrypted content stored in a memory card. This structure includes: an information processing apparatus that stores content into an information storage device such as a memory card including an access allowed block based on an access right check made on each block, and uses the content; a content usage managing server that provides content usage permission information to the information processing apparatus; and a content correspondence information providing server that provides the encryption key to be used in decrypting the encrypted content stored in the information storage device. The content usage managing server determines the block for storing the encryption key andnotifies the content correspondence information providing server of a block identifier that is the identifier of the determined block, and the content correspondence information providing server performs a process to write the encryption key into the block corresponding to the received block identifier.