Device Data Security Policy With Decryption Key Occlusion

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Solution Overview

Problem

Mixed-use devices pose a security risk due to the storage of sensitive data, as existing security measures often result in data loss or inconvenience when attempting to protect against unauthorized access, such as children accessing parental devices.

Innovation Solution

Implementing a security policy that occludes the decryption key if unauthorized access is detected, allowing recovery through advanced authentication, such as a high-entropy recovery password, to protect encrypted data while preventing unauthorized decryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If data is stored locally on a device for convenient access, then ease of operation is improved, but security is worsened due to potential unauthorized access

Engineering Contradiction:
Improveconvenient access to dataVSAvoidunauthorized access to data
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The data is segmented into encrypted form, separating the data content from its accessible state. Encryption divides the protection mechanism into key management and data storage components, allowing convenient access for authorized users while maintaining security against unauthorized access.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Encryption keys act as an intermediary between authorized users and the stored data. The keys mediate access control, allowing convenient retrieval for legitimate operations while blocking unauthorized access attempts without requiring data erasure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If security measures erase data upon detecting unauthorized access attempts, then security is improved, but loss of information and ease of operation are worsened

Engineering Contradiction:
Improveprotection from unauthorized accessVSAvoidloss of important data
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

Encryption is applied preliminarily to all sensitive data before storage, establishing security protection in advance. This preliminary security measure prevents unauthorized access without requiring reactive data erasure, thereby avoiding loss of important data while maintaining security.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The encryption system converts the potential harm of unauthorized access into a benefit by making encrypted data unreadable without proper keys. Even if unauthorized access attempts occur, the harm is neutralized because the data remains protected in encrypted form, eliminating the need for destructive countermeasures.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If security measures erase data to prevent unauthorized access, then security is improved, but ease of operation is worsened due to reconfiguration requirements

Engineering Contradiction:
Improvedata protection from unauthorized accessVSAvoiddevice functionality after security incident
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

Backup and recovery mechanisms are established beforehand to cushion against security incidents. Encrypted data can be recovered using stored keys or key recovery procedures, preventing the need for complete reconfiguration and maintaining ease of operation after security events.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

Instead of permanently discarding data through erasure, the system discards unauthorized access attempts while recovering legitimate access through key management. Encrypted data remains intact and can be recovered for authorized users, maintaining both security and operational continuity.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2812842B1Security policy for device data
Publication Date: 2020.04.29 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP2812842B1 patent drawingFigure 1
  • EP2812842B1 patent drawingFigure 2
  • EP2812842B1 patent drawingFigure 3

AI summary

Techniques for providing security policy for device data are described. In implementations, data on a device is stored in an encrypted form. To protect the encrypted data from being decrypted by an unauthorized entity, techniques enable a decryption key to be occluded if an attempt to gain unauthorized access to device data is detected. In implementations, a decryption key can be occluded in a variety of ways, such as by deleting the decryption key, overwriting the encryption key in memory, encrypting the encryption key, and so on. Embodiments enable an occluded decryption key to be recovered via a recovery experience. For example, a recovery experience can include an authentication procedure that requests a recovery password. If a correct recovery password is provided, the occluded decryption key can be provided.