Decentralized identity systems use various methods for access control and permission management, including:

1. _Attribute-Based Access Control_ (ABAC): Access is granted based on user attributes, like role or clearance level.

2. _Role-Based Access Control_ (RBAC): Access is granted based on user roles, like admin or user.

3. _Mandatory Access Control_ (MAC): Access is granted based on strict rules, like military clearance levels.

4. _Discretionary Access Control_ (DAC): Access is granted based on user discretion, like sharing personal data.

5. _Permissioned Blockchain_: Access is granted through blockchain-based permission management.

6. _Smart Contracts_: Self-executing contracts with access control rules, automating permission management.

7. _Decentralized Identity Graphs_: Graph databases storing identity relationships and access permissions.

8. _User-Managed Access_ (UMA): Users control access to their data and identity information.

These methods ensure:

1. _Granular control_: Fine-grained access control, granting access to specific resources or data.

2. _Transparency_: Clear understanding of who has access and why.

3. _Security_: Protection against unauthorized access and data breaches.

4. _Privacy_: Control over personal data and identity information.

5. _Compliance_: Adherence to regulations and standards for access control and permission management.

By utilizing these decentralized access control and permission management methods, individuals can trust that their digital identity and personal data are secure and under their control.