Secure Peripheral Pairing Using Silicon Keys for Re-Pairing

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Solution Overview

Problem

Existing secure functions on electronic devices are compromised when a secure circuit is removed and replaced with a different one, leading to security breaches.

Innovation Solution

A secure circuit on a peripheral device is paired with a secure circuit on a host device outside the factory environment using silicon keys embedded during manufacturing, establishing encrypted connections that are opaque to the application processor, enabling secure data exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a secure circuit is paired with a device in a factory environment, then security is maintained, but the device cannot be re-paired with a different secure circuit

Engineering Contradiction:
ImprovesecurityVSAvoidre-pairing capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Silicon keys are embedded in the secure circuit during manufacturing before the device is deployed. This preliminary embedding of cryptographic material enables the secure circuit to independently verify its identity and establish encrypted connections without requiring factory pairing, thus maintaining security while enabling re-pairing capabilities

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If a secure circuit is removed and replaced with a different one, then adaptability is improved, but security is compromised

Engineering Contradiction:
Improvesecure circuit replaceabilityVSAvoidsecurity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The silicon key acts as an intermediary cryptographic element that mediates between the secure circuit and the host device. When a secure circuit is replaced, the new circuit can still establish secure communication by proving possession of its embedded silicon key through encrypted challenge-response protocols, allowing replaceability without security compromise

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If encrypted connections are established between secure circuits, then security is improved, but device complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidcryptographic protocol complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cryptographic complexity is extracted from the main device logic and isolated within the secure circuit. The secure circuit independently handles key storage, encryption, and authentication protocols, while the host device only needs to initiate simple pairing commands. This extraction reduces the apparent complexity in the host device while maintaining robust security

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4291998B1Pairing protocol for peripherals with a secure function
Publication Date: 2025.12.03 APPLE INC
  • EP4291998B1 patent drawingFigure 1
  • EP4291998B1 patent drawingFigure 2
  • EP4291998B1 patent drawingFigure 3A

AI summary

Embodiments described herein provided techniques to enable peripherals configured to provide secure functionality. A secure circuit on a peripheral device can be paired with a secure circuit on a host device outside of a factory environment without compromising security by verifying silicon keys that are embedded within the secure circuit during manufacturing.