Bluetooth Pairing Circuit Using Additive Cyclic Groups

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Solution Overview

Problem

Bluetooth devices experience high power consumption and inconvenience due to extensive interactions during pairing, and security concerns arise from storing session keys in plaintext form.

Innovation Solution

Incorporating a key generating circuit, calculating circuit, storing circuit, and encrypting/decrypting circuit in both transmitting and receiving devices to generate and manage session keys within additive cyclic groups, reducing interactions and storing keys in ciphertext form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Bluetooth devices exchange device types and perform authentication interactions during pairing, then authentication security is improved, but power consumption increases and standby time is reduced

Engineering Contradiction:

Improveauthentication securityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-generating authentication tokens and session keys before the actual pairing interaction. The key generating circuit creates cryptographic key pairs in advance, and the calculating circuit prepares authentication tokens using additive cyclic groups before transmission, reducing the need for extensive real-time interactions during pairing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements self-service through automatic authentication token verification and session key derivation. The calculating circuit automatically determines whether received authentication tokens are within the additive cyclic group and derives session keys without requiring user intervention or extensive back-and-forth interactions, allowing the device to serve itself during the authentication process.

Inventive Principle:

Principle #25Self-service

2Reliability

If Bluetooth devices perform extensive authentication interactions, then authentication reliability is improved, but customer convenience deteriorates due to required participation

Engineering Contradiction:

Improveauthentication reliabilityVSAvoidcustomer convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements self-service by enabling automatic authentication token verification and session key derivation without user intervention. The calculating circuit automatically checks whether received authentication tokens belong to the additive cyclic group and derives session keys autonomously, eliminating the need for customers to manually confirm authentication through device interfaces.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent uses cryptographic tokens and session keys as intermediaries to facilitate automatic authentication. The calculating circuit generates and verifies authentication tokens as intermediary credentials, and derives session keys as intermediary secrets, enabling reliable authentication without requiring direct customer participation in the interaction process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If session keys are stored in plaintext form, then storage simplicity is improved, but security concerns increase

Engineering Contradiction:

Improvestorage simplicityVSAvoidsecurity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by transforming session keys from plaintext form to ciphertext form through encryption. The encrypting and decrypting circuit encrypts session keys using cryptographic algorithms, changing the state of the stored data from readable plaintext to encrypted ciphertext, thereby maintaining security while the storing circuit handles the encrypted form.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses encryption algorithms and cryptographic protocols as intermediaries between the session key and its storage form. The encrypting and decrypting circuit acts as an intermediary that transforms the session key into an encrypted form before storage, and can restore it when needed, providing security protection during the storage process without requiring complex security management systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250024253A1Bluetooth transmitting device, bluetooth receiving device and bluetooth pairing method

Publication Date: 2025.01.16 REALTEK SEMICON CORP

AI summary

A Bluetooth transmitting device includes a key generating circuit, a calculating circuit, a storing circuit, and an encrypting and decrypting circuit. The key generating circuit generates a transmitting-terminal algorithm identifier, a receiving-terminal algorithm identifier, a public key, and a key length. The calculating circuit generates a transmitting-terminal authentication token, and receives a receiving-terminal authentication token of a Bluetooth receiving device to determine whether the receiving-terminal authentication token is within an additive cyclic group. If the receiving-terminal authentication token is within the additive cyclic group, the calculating circuit further calculates a transmitting-terminal session key according to the transmitting-terminal algorithm identifier, the receiving-terminal algorithm identifier, the transmitting-terminal authentication token, the receiving-terminal authentication token, and the key length. The storing circuit stores the transmitting-terminal session key. The encrypting and decrypting circuit calculates a ciphertext according to the transmitting-terminal session key, the public key, and the key length.