Subset-Difference Broadcast Encryption Blacklisting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional subset-difference encryption schemes face inefficiencies in revoking compromised devices, as revoking one device often results in the revocation of multiple innocent devices due to shared keys, leading to unnecessary key distribution and access restrictions.
Innovation Solution
A subset-difference tree-based blacklisting method is employed, where a blacklist is created to systematically eliminate subset differences associated with compromised devices, allowing for the generation of substitute subsets that do not cover the revoked nodes, thereby isolating and revoking only the compromised devices while maintaining access for innocent ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional subset-difference encryption schemes revoke compromised devices by removing shared keys, then security is improved, but innocent devices are also revoked due to shared key relationships
Solution Approach 1:
The patent segments the subset-difference tree into multiple independent subsets, allowing selective revocation of compromised devices by targeting specific subsets rather than revoking all devices sharing keys with compromised ones. This enables precise control over which devices are revoked and which remain accessible.
Solution Approach 2:
The patent applies local quality by creating blacklist-specific subset differences that are localized to compromised devices only. The blacklist mechanism ensures that revocation properties are applied locally to specific devices rather than globally to all devices sharing keys, maintaining access control accuracy.
2Adaptability or versatility
If subset-difference lists are expanded to cover all possible device combinations, then coverage is improved, but computational complexity and key distribution overhead increase
Solution Approach 1:
The patent performs preliminary action by pre-computing and storing subset-difference lists in a tree structure before actual revocation operations. This allows the system to efficiently handle revocation by simply referencing pre-computed blacklist entries rather than computing all possible subset differences in real-time, reducing computational complexity.
Solution Approach 2:
The patent introduces a new dimension by organizing subset differences in a hierarchical tree structure with multiple levels. This dimensional organization allows the system to cover all possible device combinations efficiently by traversing the tree structure, reducing the computational overhead compared to flat enumeration of all subsets.
3Productivity
If the subset-difference tree structure is maintained for efficient revocation, then revocation efficiency is improved, but the system becomes vulnerable to compromised devices deriving keys from parent nodes
Solution Approach 1:
The patent extracts the security vulnerability by removing the ability of compromised devices to derive keys from parent nodes. The blacklist mechanism extracts and isolates compromised devices, preventing them from utilizing the hierarchical key derivation property of the subset-difference tree, thus maintaining key security while preserving revocation efficiency.
Solution Approach 2:
The patent introduces an intermediary mechanism (the blacklist) that mediates between the efficient subset-difference tree structure and the security requirement. The blacklist acts as an intermediary layer that allows the tree structure to maintain its efficiency while blocking compromised devices from deriving keys, thus resolving the security-efficiency trade-off.
Data Source
AI summary
An encryption scheme is provided in which subset-difference lists are generated by blacklisting subsets corresponding to compromised devices and splitting subset difference lists corresponding to the blacklisted subsets into multiple subset difference lists. In some embodiments, a subset-difference tree is generated. The subset-difference tree includes a plurality of subsets. The subset-difference tree covers a plurality of nodes. Each of the plurality of subsets has an apex node among the plurality of nodes. At least one blacklisted node of the plurality of nodes is determined. A first subset among the plurality of subsets is identified that covers the at least one blacklisted node. A plurality of substitute subsets is determined. Each of the plurality of substitute subsets overlaps the first subset and does not cover the at least one blacklisted node. The plurality of substitute subsets are substituted for the first subset.