Dynamic Broadcast Session Key Generation for Secure Multicast

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Solution Overview

Problem

Existing encryption techniques for broadcast and multicast data are insecure due to the use of static session keys, which are susceptible to attacks and require significant planning and management for distribution, especially in ad-hoc multicast sessions.

Innovation Solution

A method of generating a shared broadcast or multicast session key 'on-the-fly' using random numbers exchanged and processed independently by parties, with an offset added per packet to create a new encryption key for each transmission, preventing dictionary attacks and conserving network resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If static session keys are used for broadcast and multicast data encryption, then key distribution is simplified, but security is compromised due to susceptibility to attacks

Engineering Contradiction:

ImprovesecurityVSAvoidkey management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic session key generation where keys are created on-demand for each broadcast or multicast session rather than using static pre-distributed keys. Each party independently generates random numbers that are processed through a key derivation function to create unique session keys, ensuring security while adapting to different communication scenarios without requiring complex manual key distribution planning

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Each party independently generates its own random numbers and processes them locally to derive session keys without requiring direct key exchange or centralized key distribution. The system serves itself by having each participant contribute random values that are combined through cryptographic functions to create shared session keys, eliminating the need for complex key management infrastructure

Inventive Principle:

Principle #25Self-service

2Reliability

If static session keys are distributed to all broadcast receivers, then encryption is simplified, but the system becomes susceptible to dictionary attacks

Engineering Contradiction:

Improvesecurity against dictionary attacksVSAvoidoperational simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system generates unique session keys dynamically for each broadcast or multicast session rather than reusing static keys. Each session key is derived from random numbers generated at the time of the session, making dictionary attacks ineffective since keys never repeat and are not predictable from previous sessions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of key uniqueness by ensuring each session key is cryptographically derived from fresh random values. This transforms the key space usage from static repetition to dynamic variation, preventing attackers from using dictionary attacks across multiple sessions while maintaining operational simplicity through automated key derivation

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If static keys are distributed for multiple multicast sessions, then key management is simplified, but considerable planning and management are required

Engineering Contradiction:

Improveadaptability to ad-hoc sessionsVSAvoidkey distribution management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system adapts to ad-hoc multicast sessions by generating session keys dynamically when sessions are initiated, rather than requiring pre-planned key distribution. Each multicast session independently generates its own key material, allowing the system to flexibly accommodate spontaneous or dynamic group formations without requiring advance key management planning

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Each multicast session self-generates its encryption keys through independent random number generation and cryptographic processing by the participating parties. This eliminates the need for centralized key distribution planning and management, as the system automatically creates and manages keys for each session as needed, providing both adaptability and reduced operational complexity

Inventive Principle:

Principle #25Self-service

4Reliability

If unique session keys are generated for each broadcast, then security is improved, but key distribution and management becomes more complex

Engineering Contradiction:

Improvesession key securityVSAvoidkey exchange simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Each party independently generates random numbers and processes them locally to derive session keys without requiring direct key exchange between parties. The system achieves unique secure session keys for each broadcast while maintaining operational simplicity because each participant performs the key derivation independently using their own random values combined with the broadcast identifier, eliminating complex key distribution protocols

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9008312B2System and method of creating and sending broadcast and multicast data

Publication Date: 2015.04.14 KOOLSPAN INC

AI summary

A method of encrypting broadcast and multicast data communicated between two or more parties, each party having knowledge of a shared key, is provided. The key is calculated using values, some of which are communicated between the parties, so that the shared key is not itself transferred. Avoiding the transfer of the key offers several advantages over existing encryption methods.