Blockchain Capability Tokens for Dynamic Access Control
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Solution Overview
Problem
Existing access control systems face challenges in managing dynamic access rights, particularly in distributed systems, where changes in user roles and departmental transfers complicate tracking and interoperability, leading to potential access rights leakage and the Confused Deputy Problem.
Innovation Solution
A computer-implemented method using smart contracts on a blockchain system to create, grant, delete, and revoke capabilities, which are secure references to objects, ensuring fine-grained control and audit trails through immutable data storage, allowing for dynamic access control and authorization policies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If access control rights are managed in distributed systems with changing user roles and departmental transfers, then the system needs to be adaptable and flexible, but tracking and managing access rights becomes complex and difficult
Solution Approach 1:
The patent segments access control into discrete capability tokens that can be independently tracked and managed. Each capability represents a specific access right that can be granted, transferred, or revoked independently, making it easier to track access rights across changing user roles and departments without managing complex permission sets.
Solution Approach 2:
The patent introduces an audit trail as an intermediary mechanism that automatically records all capability grants, transfers, and revocations. This intermediary system simplifies tracking by providing a centralized, immutable record of access right propagation, eliminating the need for complex manual tracking across distributed systems.
2Adaptability or versatility
If access rights are propagated in distributed systems, then authorization flexibility improves, but access rights may spread or leak beyond known users
Solution Approach 1:
The patent implements feedback mechanisms through the audit trail that continuously monitor capability propagation. When capabilities are granted or transferred, the system automatically records these events and can trace the propagation path, providing feedback that enables detection and prevention of unauthorized access right leakage while maintaining flexible authorization.
Solution Approach 2:
The patent applies preliminary action by recording capability grants in an immutable audit trail before any potential misuse can occur. This proactive recording enables the system to track and confine access rights as they are propagated, allowing for early detection and prevention of access right leakage beyond authorized users.
3Loss of information
If traditional audit trails are used to track access rights, then access history can be recorded, but correlating access rights across different security policy models increases complexity
Solution Approach 1:
The patent creates a universal capability-based access control model that can represent and track access rights across different security policy models. The capability token and audit trail structure serve multiple functions: they can represent various types of access rights, track propagation across different departments and systems, and provide a unified view of access history, thereby simplifying correlation without losing access information.
4Reliability
If fine-grained control of access rights is implemented, then the Confused Deputy Problem can be prevented, but the system complexity increases
Solution Approach 1:
The patent segments access rights into fine-grained capability tokens that represent specific permissions. By dividing access control into discrete, traceable units, the system can precisely track which capabilities are held by which users and how they propagate, preventing the Confused Deputy Problem where unauthorized access occurs through capability misuse. The segmentation enables detailed tracking without requiring complex policy enforcement at each access point.
Data Source
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AI summary
This disclosure describes dynamic access control using capabilities (via dynamic access control interface (150)) on a blockchain system (180). The blockchain data structure is a time- stamped list of blocks, chained together cryptographically. In this disclosure, capabilities can be recorded on a blockchain system (via capabilities storage (170)) and thus access propagation is known. This makes revocation of access achievable by recording a new transaction, which in effect removes the previous authorization. There will be no change to transaction history and instead a new transaction records (170) the current status of the capability. An example implementation on a blockchain system (180) is given in Ethereum, which allows programs called "smart contracts" to run as transactions.