Product Overview

The solution "pow.do" is a privacy-focused, decentralized proof-of-work time tracking system built around Electron (client side), Blossom storage, Nostr protocol (events & relays), and a local Kimai instance for persisting time-tracking data.

High-level Architecture

The overall solution is made up of:

• Local Client (actual time tracker, an electron desktop app)
  • captures ActivityWatch data & screenshots
  • creates encrypted ZIP file and uploads to Blossom
  • creates signed Nostr Event linking to the ZIP file on Blossom
  • gift-wraps this event (NIP-17) and publishes it to a Nostr relay
• Public Server (with Blossom file storage and Nostr event relay)
  • Blossom files regularly discarded
  • Relay whitelisted to end user npubs
• Private Server (with Data Vending Machine, Kimai time tracking instance and a DB)
  • DVM monitors relay, picks up Nostr Event
  • DVM fetches ZIP file from Blossom
  • DVM sends collected Activity Watch data into a local DB
  • DVM updates Kimai instance with time tracking data

Architecture Diagram

The architecture looks like this:

Component Design

1. Electron App (Client side)

• Framework: ElectronJS, Chromium frontend.
• Responsibilities:
  • Periodically capture user screenshots.
  • Query the local ActivityWatch API to collect usage data on a regular interval.
  • Bundle screenshots & ActivityWatch data as encrypted zip files and upload to Blossom server.
  • Use Blossom API to persist data securely.
  • Create signed Nostr Events referencing the stored Blossom files.
  • Gift-wrap (encrypt/secure via NIP-17) the Nostr event for enhanced privacy/security.
  • Publish the gift-wrapped event to a Nostr relay.
• Required Libraries/Tools:
  • Electron framework (UI & client app)
  • Node.js scripting
  • ActivityWatch API Client (REST API calls)
  • Blossom API Client (REST API - file upload handling)
  • Nostr protocol JS client (e.g., nostr-tools library)
  • ZIP/compression libraries (adm-zip, archiver)
  • nostr-tools (JavaScript) or equivalent
  • encryption/decryption utility supporting NIP-17

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2. Blossom File Storage Service

• Description: Decentralized hash-based file storage to securely store ZIP archives of screenshots & ActivityWatch data.
• Data Flow: Electron app → encrypted zip → Blossom Server (via REST API)
• Security & Privacy: Files are hash-identified, no direct user-identification metadata exposed. Content is encrypted.

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3. Nostr Relay

• Description: Decentralized event publishing via signed JSON messages (Nostr event).
• Nostr Usage:
  • Publishing: Electron client creates Nostr events, signs them, and publishes to relay servers.
  • Gift-wrapping (NIP-17): Electron client encrypts events using NIP-17 before publishing, ensuring that only the DVM can decrypt and access the Blossom file URLs.

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4. Data Vending Machine (DVM)

• Description: The DVM is a separate backend (or daemon) that:

  • Subscribes to the chosen Nostr relay.
  • Receives and decrypts the gift-wrapped Nostr events (using NIP-17 technique).
  • Fetches the referenced ZIP file from Blossom (via Blossom API).
  • Unzips & extracts data (screenshots/activity logs).
  • Parses extracted activitywatch / screenshot data and sends it to the DB
  • Tracks ongoing time usage and updates the dedicated Kimai API endpoints.

• Client-to-DVM Data Flow:

  Electron Client 
    → Nostr event signed & gift-wrapped event with Blossom file URL
    → Sent to relay
    → DVM subscribes to Nostr relay feed, receives gift-wrapped event
  

• Data Flow in DVM:

  Nostr Relay → DVM (relay subscription)
    → Event Decryption (NIP-17)
    → Blossom download (via hash)
    → Data Parsing (python/node — depending on language preference)
    → Kimai API call (add/update time-entry, activity, and time data)
  

• Libraries & dependencies: -Python or Node.js client for Nostr events (nostr-tools in Node)

  • HTTP client for Blossom API (authenticated/file download)
  • HTTP client for Kimai API updates/addition of entries (requests or axios)
  • ZIP utilities for unzipping (e.g., Node.js's adm-zip or unzip)

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5. Kimai (Local Instance)

• Description: Open-source time tracking tool storing final extracted data.
• Deployed Local/Privately: As per your requirements—keeping all time-tracked data internal/private.
• Data Flow:

  DVM → Kimai API (insert/update entries)
  

• Setup Considerations:
  • Host Kimai locally in a container with no public IP access.
  • DVM accesses Kimai API endpoints directly.

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Security & Privacy Considerations

• Event Encrypting & Security: Utilizing NIP-17 ensures additional confidentiality.
• File hashing/storage (Blossom): Secure with cryptographic hashing, eliminating data manipulation risks.
• Privacy: Nostr Relay protects both Server and Client IPs
• Decentralization: Leveraging open protocols (Nostr), distributed storage systems (Blossom).
• Traceability: The data trail remains verifiable and secured (signed events, cryptographic proof via Blossom hashes, encrypted via NIP-17).
• Flexibility: Easy to scale or swap out components later if required (Blossom → alternative storage, Kimai → other time-tracking tools).

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High-level Sequence Diagram (text-based)

Electron App:
  ├─ Capture Screenshots & ActivityWatch data
  └─ Upload ecnrypted ZIP to Blossom server (API)

Electron App:
  ├─ Create JSON Nostr Event (signed via keypair)
  ├─ Gift-wrap (NIP-17 encryption)
  └─ Publish event to Nostr relay

DVM (Backend):
  ├─ Listen to Relay for events
  ├─ Decrypt Nostr Event via NIP-17 (Gift-wrap)
  ├─ Use content from event to download ZIP from Blossom
  ├─ Extract ZIP and parse data
  └─ Upload parsed data to DB
  └─ Add time entries to Kimai via REST/API

Mermaid flow: