# SRS-04 — AtlasOS – Calypso Authentication & IAM

Version: 1.0  
Identity Sources: Local (PostgreSQL), LDAP, OIDC SSO  
Date: 2025

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## 1. Purpose
Defines authentication, authorization, and audit requirements for AtlasOS – Calypso.

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## 2. Authentication Methods
- Local authentication with Argon2id password hashing
- LDAP bind authentication
- OIDC-based SSO integration

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## 3. Authorization
- Role-Based Access Control (Admin, Operator, ReadOnly)
- Permission enforcement per API endpoint

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## 4. Audit Logging
- Login success and failure
- Configuration changes
- Privileged system operations

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## 5. Acceptance Criteria
1. Local login works correctly.
2. LDAP authentication functions as expected.
3. OIDC login succeeds.
4. Audit trail is complete and immutable.
