Offline Shared Security Key Calculation via Nonce Management

Solution Overview

Problem

Existing secure communication protocols are vulnerable to replay attacks, where intercepted communications can be retransmitted during future sessions, compromising security and disrupting communication sessions.

Innovation Solution

Implementing a system that generates and manages unique nonces for each communication session, allowing for the creation of session keys that are specific to each session, thereby preventing the reuse of encryption keys and identifying invalid nonces to prevent replay attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional secure communication protocols are used, then security is maintained, but the system is vulnerable to replay attacks where intercepted communications can be retransmitted during future sessions

Engineering Contradiction:

ImprovesecurityVSAvoidreplay attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system pre-generates and stores a list of valid nonces before communication sessions begin. During session establishment, the system validates nonces against this pre-established list, allowing rapid verification without real-time computation. This preliminary preparation enables the system to quickly identify and reject replayed nonces while maintaining strong security.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where used nonces are tracked and recorded during communication sessions. This feedback loop allows the system to recognize when a nonce has been previously used and reject it in subsequent sessions, preventing replay attacks while maintaining efficient communication.

Inventive Principle:

Principle #23Feedback

2Reliability

If unique nonces are provided and validated for each communication session, then replay attacks are prevented, but the process of initiating communication sessions experiences increased delay

Engineering Contradiction:

Improveprotection from replay attacksVSAvoidsession initiation delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system pre-generates and stores a list of valid nonces before communication sessions begin. During session establishment, the system validates nonces against this pre-established list, allowing rapid verification without real-time computation. This preliminary preparation enables the system to quickly identify and reject replayed nonces while maintaining strong security.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of generating unique nonces through complex real-time processes, the system uses pre-generated nonce values that are stored and validated. This approach replaces computationally intensive real-time nonce generation with simple lookup and validation operations, significantly reducing session initiation delay while maintaining security.

Inventive Principle:

Principle #26Copying

3Productivity

If session keys are generated using pre-shared nonces, then communication speed and bandwidth are maintained at high levels, but the complexity of nonce management increases

Engineering Contradiction:

Improvecommunication speedVSAvoidnonce management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Instead of generating unique nonces through complex real-time processes, the system uses pre-generated nonce values that are stored and validated. This approach replaces computationally intensive real-time nonce generation with simple lookup and validation operations, significantly reducing session initiation delay while maintaining security.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The system uses disposable nonce values that are pre-generated and then discarded after use. This approach simplifies nonce management by treating nonces as single-use items rather than requiring complex tracking and regeneration mechanisms, reducing overall system complexity while maintaining high communication performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS8615651B1Offline shared security key calculation

Publication Date: 2013.12.24 GOOGLE LLC

AI summary

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for offline shared security key calculation. In one aspect, a method includes entering a first secure communication session with a remote device. A plurality of nonces are provided to the remote device during the first secure communication session. The first secure communication session is exited. A communication is received from the remote device after exiting the first communication session. The communication includes an indication of one of the plurality of nonces. A session key is generated using the indicated one of the plurality of nonces. A second secure communication session is entered with the remote device using the generated session key. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.