Wireless Data Protection via Dual-Encrypted Key Management

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Solution Overview

Problem

Existing mobile device backup mechanisms cannot effectively backup and restore cryptographic keys, especially when a device is lost or inaccessible, as they require user intervention or cannot access encrypted data.

Innovation Solution

A system that encrypts and manages cryptographic keys by using a file key encrypted with a class encryption key and then a public key associated with backup keys, allowing secure transmission and storage on a backup device, and enables restoration of encrypted data to a primary device, including generation of initialization vectors and handling password changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a backup mechanism copies data to a backup system, then data recoverability is improved, but the system cannot backup data when the mobile device is locked or inaccessible

Engineering Contradiction:
Improvedata recoverabilityVSAvoidbackup capability under locked condition
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces cryptographic intermediaries (backup keys, encrypted file keys) that enable backup operations without requiring direct access to the locked device data. The backup system uses these intermediaries to decrypt and backup data even when the primary device is locked, resolving the contradiction between maintaining security and enabling backup capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary cryptographic key management and encryption setup before the actual backup is needed. By pre-configuring backup keys and encryption mechanisms, the system enables automatic backup capability that works even when the device is locked, without requiring user intervention at backup time.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If a backup mechanism requires user input to unlock the device, then data access is improved, but user convenience deteriorates

Engineering Contradiction:
Improvedata accessVSAvoiduser intervention time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The backup system performs self-service by automatically managing cryptographic keys and executing backup operations without requiring user intervention. The system uses pre-configured backup keys to automatically decrypt and backup data, eliminating the need for users to manually unlock the device or initiate backup processes.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If cryptographic keys are transmitted wirelessly to a backup device, then backup capability is improved, but security against interception deteriorates

Engineering Contradiction:
Improvewireless backup capabilityVSAvoidinterception risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by encrypting cryptographic keys with public keys before wireless transmission. This pre-encryption protects the keys from interception during transmission, as any intercepted data remains encrypted and unusable without the corresponding private keys, thus neutralizing the security threat of wireless transmission.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system replaces direct mechanical/key-based access with cryptographic substitution. Instead of transmitting plaintext keys or requiring physical device access, the system uses public-key cryptography to securely transmit encrypted key material, substituting a secure cryptographic mechanism for less secure alternatives.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2730049B1System and method for wireless data protection
Publication Date: 2020.04.22 APPLE INC
  • EP2730049B1 patent drawingFigure 1
  • EP2730049B1 patent drawingFigure 2~3
  • EP2730049B1 patent drawingFigure 4~5

AI summary

Disclosed herein are systems, methods, and non-transitory computer-readable storage media for wireless data protection utilizing cryptographic key management on a primary device and a backup device. A system encrypts a file with a file key and encrypts the file key twice, resulting in two encrypted file keys. The system encrypts each file key differently and stores a first file key on the primary device and transmits one of the encrypted file keys in addition to the encrypted file to a backup device for storage. On the backup device, the system associates the encrypted file key with a set of backup keys protected by a user password. In one embodiment, the system generates an initialization vector for use in cryptographic operations based on a file key. In another embodiment, the system manages cryptographic keys on a backup device during a user password change.