Escrow Key Segmentation for IoT Security

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Solution Overview

Problem

Existing secure communication systems for IoT devices face vulnerabilities due to interception of cryptographic keys during transmission and centralized key storage being a prime target for hackers, compromising security.

Innovation Solution

A system that generates a subject key managed by a policy, encrypts it using a key secret and an escrow public key, and transmits it through an escrow service, ensuring the key remains encrypted across multiple parties, with only authorized entities able to decrypt it using their private keys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cryptographic keys are transmitted during setup or key rotation, then secure communication can be established or updated, but the keys become vulnerable to interception during transmission

Engineering Contradiction:
Improvesecurity of key transmissionVSAvoidinterception vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The encryption key is divided into multiple key shares using secret sharing methodology. Each key share is stored in a different location or held by a different entity, so that no single point of failure exists. The key can only be reconstructed when a sufficient number of key shares are combined, preventing interception from compromising the entire key.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A trusted intermediary system is introduced to manage key distribution and reconstruction. This intermediary coordinates the secure exchange of key shares between devices and ensures that key material never exists in transit in its complete form, eliminating the interception vulnerability during transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If cryptographic keys are stored centrally for easy management, then key distribution is simplified, but the centralized storage becomes a prime target for hackers

Engineering Contradiction:
Improvekey management convenienceVSAvoidcentralized storage vulnerability
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The centralized key storage is segmented into multiple distributed key shares. Instead of storing complete keys in a single location, the system distributes key shares across multiple secure locations. This maintains ease of management through automated distribution while eliminating the single point of failure that makes centralized storage vulnerable to attacks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different key shares are stored with different security properties and access requirements in different locations. Each key share has localized security measures appropriate to its specific storage environment, creating a distributed architecture where compromise of one location does not endanger the entire key system.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If complete cryptographic keys are transmitted between devices, then secure communication can be established, but the transmission becomes a security risk

Engineering Contradiction:
Improvekey establishment capabilityVSAvoidtransmission security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The key establishment process uses segmented key shares instead of complete keys. Each device receives only a portion of the key material that is useless without the other shares. This maintains the ability to establish secure communication while eliminating the security risk of transmitting complete keys between devices.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3642996B1Authorization key escrow
Publication Date: 2023.08.23 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3642996B1 patent drawingFigure 1
  • EP3642996B1 patent drawingFigure 2
  • EP3642996B1 patent drawingFigure 3

AI summary

A key originating device generates a subject key that is managed by a policy. The subject key may be generated and the policy configured at the instruction of a user, an application, or a service, such as a provisioning service. The policy that manages the subject key identifies at least one or more entities that are authorized to receive the subject key. The subject key is provided varying layers of encryption as it is communicated between the originating device, an escrow services, and an authorized entity.