Decentralized MA-ABE for Fully Adaptive Authority Corruption
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Solution Overview
Problem
Existing multi-authority attribute-based encryption (MA-ABE) schemes lack fully adaptive security, as they assume static corruption of authorities and do not support decentralized systems where any party can join as an authority at any time without a predetermined maximum number of authorities, failing to capture realistic attack scenarios.
Innovation Solution
A decentralized MA-ABE scheme is developed that provides fully adaptive security by using bilinear groups with standard polynomial hardness assumptions, allowing any party to join as an authority and supporting adaptive corruption of authorities, with a construction based on composite and prime order bilinear groups, utilizing a novel dual system with dual subsystems to ensure collusion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single master authority is used in ABE schemes, then key management and collusion resistance are simplified, but the system lacks decentralization and cannot support multiple independent authorities
Solution Approach 1:
The system segments the authority function into multiple independent authorities, each controlling specific attributes. This allows decentralization where no single authority manages all attributes, and each authority operates independently to issue keys for its controlled attributes without coordinating with others.
Solution Approach 2:
The encryption scheme uses a universal framework that works with any number of authorities and any access policy structure. The system universally handles multiple authorities through a common cryptographic construction that doesn't require authority-specific coordination mechanisms.
2Adaptability or versatility
If the maximum number of authorities is predetermined, then security proofs become feasible, but the system cannot dynamically accommodate new authorities
Solution Approach 1:
The system dynamically accommodates authorities by using a security parameter that bounds the number of authorities per ciphertext rather than the total system authorities. New authorities can join and issue keys without system reconfiguration, as long as any single ciphertext involves at most the bounded number of authorities.
Solution Approach 2:
The security proof performs preliminary actions by bounding the authority count per ciphertext and using this bound in the security reduction. This preliminary bounding enables security proofs while allowing the system to dynamically grow in practice.
3Adaptability or versatility
If static corruption of authorities is assumed, then security proofs are simpler, but the system cannot capture realistic adaptive attack scenarios
Solution Approach 1:
The security model performs preliminary actions by allowing the adversary to adaptively corrupt authorities and make key queries throughout the game. The security proof then uses this adaptive model with a bounded authority parameter to achieve fully adaptive security guarantees.
Solution Approach 2:
The security proof incorporates feedback from adaptive corruption queries and key queries made by the adversary during the game. The proof structure adapts to the adversary's actions while maintaining security guarantees through the bounded authority parameter.
Data Source
AI summary
The invention relates to systems, methods, network devices, and machine-readable media for encrypting and decrypting messages in a decentralized multi-authority attribute-based encryption (MA-ABE) scheme that is provably fully-adaptively secure, specifically, secure against an attacker that may corrupt some of the authorities as well as perform key queries adaptively throughout the lifetime of the system.