Variable Key Ladder for Conditional Access Security
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Solution Overview
Problem
Conventional conditional access systems in media program stream delivery systems use fixed encryption and decryption key hierarchies, which are inflexible and unable to accommodate future security needs or new business models, failing to provide increased security and counteract hacker attacks.
Innovation Solution
A system and method for generating and managing variable key ladders, where keys are determined based on network connection and configuration data, allowing for dynamic configuration of encryption and decryption keys using a device key, session or category key, and control words, enabling flexible key management and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed encryption and decryption key hierarchies are used in conventional conditional access systems, then system stability and simplicity are maintained, but the system cannot accommodate future security needs, new business models, or counter hacker attacks
Solution Approach 1:
The patent implements a dynamic key ladder structure where the number of encryption/decryption tiers can be configured variable (e.g., 1 to 7 tiers) rather than fixed. This allows the system to adapt its complexity level according to security requirements, business models, and threat levels, directly resolving the contradiction between adaptability and complexity by making the system structure flexible and reconfigurable
Solution Approach 2:
The key ladder system is designed to support multiple functions and configurations within a single framework. It can operate with different numbers of tiers (1-7), support various key types (control words, program keys, session keys, category keys), and accommodate different business models (subscription, pay-per-view, impulse purchase). This multi-functionality allows the system to meet diverse future security needs without requiring completely separate systems, thus improving adaptability while managing complexity
2Reliability
If conventional fixed key systems are used, then implementation simplicity is maintained, but the system fails to provide increased security and flexibility for new business models
Solution Approach 1:
The patent segments the key hierarchy into multiple distinct tiers (control word tier, program key tier, session key tier, category key tier) that can be independently configured and managed. Each tier serves a specific security function and can be optimized separately. This segmentation allows the system to achieve high security through multiple layers while maintaining operational flexibility by allowing selective configuration of each segment based on specific business needs
Solution Approach 2:
The system allows dynamic configuration of the key ladder structure, enabling operators to adjust the number of tiers and key types based on security requirements and business models. The system can be configured to use 1-7 different tiers depending on the security level needed, providing both high security capability and operational flexibility to adapt to different scenarios
3Duration of action of stationary object
If hardware state machines with fixed key hierarchies are used, then system stability is maintained, but the system is not modifiable and cannot extend its life cycle
Solution Approach 1:
The patent replaces fixed hardware state machines with a dynamic, reconfigurable key ladder system that can be modified through software configuration. The system supports adding, removing, or reconfiguring key tiers and types without hardware changes, enabling the system to evolve with changing security requirements and extend its operational life cycle while maintaining stability through structured design
Solution Approach 2:
The system allows modification of key hierarchy parameters such as the number of tiers (1-7), key types at each tier, and key generation algorithms. By enabling parameter changes without requiring hardware redesign, the system can adapt to new security threats and business models, thereby extending its life cycle while maintaining operational stability through controlled parameter adjustment
4Object-affected harmful factors
If conventional CA systems are used, then current operational requirements are met, but the system cannot counter future hacker attacks or accommodate new business models
Solution Approach 1:
The patent implements a dynamic key ladder with 1-7 configurable tiers that can be adjusted based on threat levels and security requirements. This dynamic structure allows the system to increase security complexity in response to hacker attacks while managing overall system complexity through modular design, enabling the system to resist future attacks adaptively rather than being locked into a fixed complexity level
Solution Approach 2:
The key ladder system combines multiple key types (control words, program keys, session keys, category keys) and encryption algorithms in a composite hierarchical structure. This composite approach creates multiple layers of security that are more resistant to hacking attempts, as attackers must compromise multiple key tiers rather than a single key hierarchy, while the structured composite design manages the inherent complexity
Data Source
AI summary
A method of generating encryption and decryption keys for a multiple tier, variable key ladder (VKL) hierarchy includes determining a device key based on network connection and configuration data contained in conditional access system firmware, decrypting and extracting a session or category key from an input media stream or an Entitlement Management Message using the device key, and configuring a key ladder in response to at least one Entitlement Control Message (ECM), wherein the key ladder comprises the device key and at least one of (i) a program key, (ii) the session or category key, and (iii) at least one control word.