Subscriber Revocation in Publish-Subscribe Networks Using Attribute-Based Encryption
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Solution Overview
Problem
Current attribute-based encryption (ABE) systems face challenges in efficient revocation, as time-based key revocation incurs network and processing costs and does not allow for immediate revocation, while trusted proxies raise performance and security concerns.
Innovation Solution
A tree data structure is generated with leaf nodes representing subscribers, subtrees representing different likelihoods of ABE key revocation, and ABE keys are assigned to ensure that revoked subscribers are excluded from decrypting payloads, allowing for immediate revocation without relying on key expiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-based ABE key revocation is used, then revocation can be achieved, but network and processing costs increase and immediate revocation is not possible
Solution Approach 1:
The patent segments the set of ABE keys into multiple subsets, where each subset corresponds to a specific subset of subscribers. By dividing the key management into discrete, manageable segments, the system can selectively revoke access for specific subscriber groups without affecting the entire system, enabling immediate revocation while maintaining efficiency.
Solution Approach 2:
The patent implements dynamic key assignment where subscribers are assigned different numbers of ABE keys based on their revocation likelihood. High-risk subscribers receive more keys that can be quickly revoked, while low-risk subscribers receive fewer keys. This dynamic approach allows the system to adapt revocation strategies to individual subscriber profiles, achieving immediate revocation when needed without unnecessary processing overhead.
2Reliability
If time-based ABE key revocation is used, then revocation can be achieved, but processing costs increase
Solution Approach 1:
The patent applies local quality by assigning different numbers of ABE keys to different subscriber groups based on their individual revocation risks. Subscribers with higher revocation likelihood receive more keys and thus have higher processing costs when revoked, while subscribers with lower risk receive fewer keys. This localized differentiation optimizes processing efficiency by concentrating resources on high-risk cases rather than treating all subscribers uniformly.
Solution Approach 2:
The system performs preliminary actions by pre-calculating and pre-assigning ABE keys to subscribers based on their revocation likelihood before any revocation event occurs. This preliminary key assignment allows the system to respond immediately to revocation requests without needing to perform complex key generation or distribution operations at the time of revocation, significantly reducing processing costs.
3Adaptability or versatility
If ABE keys are assigned to all subscribers, then all subscribers can decrypt payloads, but ciphertext expansion increases
Solution Approach 1:
The patent applies partial action by assigning ABE keys selectively rather than universally. Instead of giving every subscriber the full set of keys, the system assigns only the necessary number of keys to each subscriber based on their revocation likelihood and access requirements. This partial key assignment reduces the total number of keys that need to be managed in ciphertexts, thereby reducing ciphertext expansion while maintaining adequate access capability for all authorized subscribers.
Data Source
AI summary
Techniques for subscriber revocation in a publish-subscribe network using attribute-based encryption (ABE) are disclosed, including: generating a tree data structure including leaf nodes representing subscribers, subtrees of the tree data structure representing subsets of subscribers having different likelihoods of ABE key revocation; generating ABE keys associated with edges in the tree data structure; assigning ABE keys to the leaf nodes, each leaf node being assigned a subset of the ABE keys associated with edges that form a path from a root node to the leaf node; based at least on a revocation record that indicates one or more revoked subscribers, determining a minimal subset of ABE keys that covers all non-revoked subscribers; and encrypting a payload using an encryption policy requiring at least one ABE key in the minimal subset of the ABE keys, to obtain a ciphertext that is not accessible to the one or more revoked subscribers.