Module user 

User system for Eidetica.

Provides multi-user account management with per-user key storage, database tracking, and sync preferences.

Architecture

• Instance: Manages infrastructure (user accounts, system databases, backends)
• User: Handles contextual operations (database access, key management) via sessions

The user’s root signing key is stored in _users as types::UserCredentials (encrypted or unencrypted). Each user has a private database (_user_<username>) owned by the user’s root key (Admin(0)), with the device key granted Read permission. The private database stores:

• keys: Additional Ed25519 keypairs with per-database SigKey mappings
• databases: Tracked databases with sync preferences
• settings: User configuration

Key Management

Keys are Ed25519 keypairs. The root key is encrypted at rest using the user’s password (Argon2id key derivation + AES-256-GCM). Decryption failure IS password verification — no separate password hash is stored. Each key can authenticate with multiple databases via SigKey mappings, which are auto-discovered when tracking a database.

Sync Settings

Per-database sync preferences (types::SyncSettings):

• sync_enabled: Master switch
• sync_on_commit: Trigger sync on each commit
• interval_seconds: Periodic sync interval

When multiple users track the same database, settings are merged to use the most aggressive settings.

Re-exports

pub use admin::InstanceAdmin;

pub use errors::UserError;

pub use key_manager::UserKeyManager;

pub use session::DatabaseBuilder;

pub use session::User;

pub use types::*;

Modules

admin

Instance-admin capability view.

crypto

Cryptographic functions for user system

errors

Error types for the user system

key_manager

User key manager for session-based key management

session

User session management

system_databases

System database initialization for the user system

types

Core data types for the user system