Anonymous Key Verification via Virtual Index and Local Revocation Lists
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anonymous authentication methods face inefficiencies in verifying key validity, particularly when revocation lists grow in length, leading to increased computation time and delayed service access for users seeking immediate authentication.
Innovation Solution
A method and server configuration that generate a local revocation list and calculate a virtual index to verify key validity, allowing the service provision server to efficiently determine if a key is valid or revoked by comparing the virtual index with the local revocation list.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the online key update method is used to verify key validity, then the service user can be prevented from using revoked keys, but the computation time and service delay increase significantly when the revocation list grows in length
Solution Approach 1:
The patent divides the centralized revocation list into distributed time-lock puzzles that are segmented across multiple service providers. Each service provider maintains a local view of the revocation list based on their specific service domain, rather than all providers maintaining the complete centralized list. This segmentation reduces the computational burden on individual providers and enables parallel verification processes.
Solution Approach 2:
The patent implements preliminary action by pre-computing time-lock puzzles and distributing them to service providers before actual key revocation occurs. The revocation list is built incrementally through time-lock mechanisms, allowing service providers to prepare verification structures in advance rather than computing them in real-time when a revocation check is needed.
2Reliability
If the VLR method is used where service providers continuously receive revocation lists, then key revocation can be verified, but the verification time is lengthened proportionally to the revocation list length
Solution Approach 1:
The patent applies local quality by enabling each service provider to maintain a customized local revocation list tailored to their specific service domain. Instead of all providers using the same global revocation list, each provider optimizes their local list to include only the portions relevant to their services, reducing verification time and computational overhead while maintaining revocation verification capability.
Solution Approach 2:
The centralized revocation list is segmented into domain-specific subsets that are distributed to appropriate service providers. This segmentation allows parallel verification across multiple providers simultaneously, with each provider working on a smaller, more manageable portion of the overall revocation data, thereby increasing overall verification productivity.
3Reliability
If unique keys are issued to service users in anonymous authentication, then user anonymity is maintained, but key validity comparison becomes impossible without exposing the keys
Solution Approach 1:
The patent introduces time-lock puzzles as an intermediary mechanism between the unique anonymous keys and the revocation verification process. These puzzles act as a mediator that enables validity comparison without requiring direct exposure of the underlying keys. The time-lock puzzles transform the verification problem from direct key comparison into a computational puzzle-solving process that preserves anonymity while enabling revocation checks.
Solution Approach 2:
The patent changes the verification parameter from direct key values to time-lock puzzle solutions. Instead of comparing keys directly (which would compromise anonymity), the system transforms the verification task into solving computational puzzles where the solution proves key validity without revealing the key itself. This parameter transformation maintains anonymity while enabling effective revocation verification.
Data Source
AI summary
Disclosed herein is a method of verifying key validity and a server for performing the method. The method is configured such that a service provision server verifies key validity in an anonymous service for providing local linkability. The service provision server receives a revocation list. A local revocation list is generated using the received revocation list and a secret key. A virtual index of a service user required to verify key validity is calculated. Whether a key of the service user is valid is verified, based on whether the virtual index is included in the local revocation list.