blockbuster

README

Blockbuster: Seamless Video Monetization with Lightning Network

Blockbuster is a video sharing platform that allows content creators to monetize their videos instantly using the L402 protocol & the Lightning Network.

With just an email sign-up, creators can upload and start earning, while viewers can purchase access using their public keys without creating accounts.

You can use blockbuster at https://blockbuster.fewsats.com

How It Works

1. Content Creators upload videos and get L402 URIs
2. Viewers use public keys (e.g., Nostr ID) to purchase access
3. L402 & Lightning Network facilitates instant, low-cost payments

Video Upload and L402 URI Generation

When a content creator uploads a video, the system:

1. Uploads the video to storage
2. Generates a unique L402 URI for the video
3. Stores video metadata and L402 URI in the database

L402 URI Scheme

An L402 URI is generated for each uploaded video. It follows this scheme:

l402://blockbuster.fewsats.com/video/info/79c816f77fdc4e66b8cd18ad67537936

and contains the following information in JSON format.

{
  "version": "1.0",
  "name": "How to focus and think deeply | Andrew Huberman and Lex Fridman",
  "description": "Lex Fridman Podcast full episode:  ...",
  "cover_url": "https://pub-xxxerea.r2.dev/cover-images/79c816f77fdc4e66b8cd18ad67sfas537936",
  "content_type": "video",
  "pricing": [
    {
      "amount": 1,
      "currency": "USD"
    }
  ],
  "access": {
   "endpoint": "https://blockbuster.fewsats.com/video/stream/79c816f77fdc4e66b8cd18ad67537836",
    "method": "POST",
    "authentication": {
      "protocol": "L402",
      "header": "Authorization",
      "format": "L402 {credentials}:{proof_of_payment}"
    }
  }
}

Creators can share this URI, which provides information about the content and the endpoint where you can pay for it.

Buy video with L402 URI

The process of purchasing access to a video using an L402 URI involves several steps:

1. Fetch Video Info: The viewer's client fetches video metadata through the L402 URI.

   GET https://blockbuster.fewsats.com/video/info/79c816f77fdc4e66b8cd18ad67537936
   

   Server responds with JSON:

   {
     "version": "1.0",
     "name": "How to focus and think deeply | Andrew Huberman and Lex Fridman",
     "description": "Lex Fridman Podcast full episode: ...",
     "cover_url": "https://pub-xxxerea.r2.dev/cover-images/79c816f77fdc4e66b8cd18ad67sfas537936",
     "content_type": "video",
     "pricing": [
       {
         "amount": 100,
         "currency": "USD"
       }
     ],
     "access": {
       "endpoint": "https://blockbuster.fewsats.com/video/stream/79c816f77fdc4e66b8cd18ad67537836",
       "method": "POST",
       "authentication": {
         "protocol": "L402",
         "header": "Authorization",
         "format": "L402 {credentials}:{proof_of_payment}"
       }
     }
   }
   

2. Request Payment Challenge:

The user sends request payment to the L402 endpoint, with their public key, domain (ie. blockbuster.fewsats.com), current timestamp and a signed domain:timestamp message .

POST https://blockbuster.fewsats.com/video/stream/79c816f77fdc4e66b8cd18ad67537836
{
    "pub_key": "03...public_key...",
    "domain": "blockbuster.fewsats.com",
    "timestamp": 1686123456,
    "signature": "304...signature..."
}

The signature and public key serve multiple purposes:

1. Proves that the request comes from private key owner.
2. Prevents unauthorized access and tampering with the request.
3. Protects against replay attacks by including a timestamp.

This approach allows for authentication without requiring traditional user accounts and previous sign up.

1. Server Processing: The server handles the request as follows:

   func StreamVideo(request) {
     // Validate the signature
     if !ValidateSignature(request.PubKey, request.Signature, request.Domain, request.Timestamp) {
       return ErrorResponse("Invalid signature")
     }
   
     // Create L402 challenge
     challenge = CreateL402Challenge(request.PubKey, videoExternalID)
   
     // Respond with 402 Payment Required status and challenge
     return PaymentRequiredResponse(challenge)
   }
   

   The 402 Payment Required challenge is included in the Www-Authenticate header and contains the Lightning Invoide and a unique macaroon tied to the user's public key:

   HTTP/1.1 402 Payment Required
   Www-Authenticate: L402 macaroon="AGIAJEemVQUTEyNCR0exk7ek90Cg==", invoice="lnbc1500n1..."
   

2. Paying the Invoice: The viewer pays the Lightning invoice using their preferred wallet.

   After payment, the viewer sends another request including the macaroon and preimage:

   POST https://blockbuster.fewsats.com/video/stream/79c816f77fdc4e66b8cd18ad67537836
   Authorization: L402 macaroon:preimage
   

3. Server Verification and Response: The server verifies the credentials and responds with the video URL:

   func StreamVideo(request) {
     paymentHash = ValidateL402Credentials(request.AuthorizationHeader)
     if paymentHash == "" {
       return ErrorResponse("Invalid credentials")
     }
   
     RecordPurchaseAndView(videoExternalID, paymentHash)
     streamURLs = GenerateStreamURL(videoExternalID)
     return SuccessResponse(streamURLs)
   }
   

   The response include 2 URLs to stream the video either using HLS or Dash formats. URLs can be used either in browser-based or desktop video players.

   {
     "hls_url": "https://videodelivery.net/9876543210abcdef/manifest/video.m3u8",
     "dash_url": "https://videodelivery.net/9876543210abcdef/manifest/video.mpd"
   }
   

This flow ensures secure, account-less authentication and payment for video access using the L402 protocol and Lightning Network.

System Architecture

Blockbuster is written in golang and built with a modular architecture. The main three modules are video, auth and l402.

Video

Video module handles:

• upload video proccess /video/upload
• L402-protected stream video /video/stream/:id
• L402 URI video info /video/info/:id
• list user videos /user/videos

Auth

Auth module is responsible of email authentication system for content creators. * Email login link /auth/login, /auth/logout * User info /me

• Viewers using a public key using auth middleware l402/authenticator.go

L402

The L402 module defines an authenticator l402/authenticator.go that is responsible for:

• Protecting videos behind a L402 paywall
• Minting macaroons tied to the viewer public key
• Verifying the signature sent on the payment requests

Configuration and Deployment

The system is highly configurable through the sample-config.conf file. Key settings include:

• Database connection
• Storage service
• Lightning Network provider
• L402 protocol settings

Run the server

1. Clone the repository
2. Copy sample-config.conf into blockbuster.conf and configure:
   • Database connection (defaults to SQLite)
   • Storage service
   • Lightning Network provider
   • L402 protocol settings
3. Run the server:

   go run cmd/server/main.go
   

Contributing

We welcome contributions!

License

Blockbuster is released under the MIT License.