WhatsApp Flows Encrypted Data Exchange Workflow

Summary

This workflow enables secure end-to-end encrypted data exchange with WhatsApp Flows for interactive applications inside Whatsapp. It implements the WhatsApp Business Encryption protocol using RSA for key exchange and AES-GCM for payload encryption, providing a secure channel for sensitive data transmission while interfacing with WhatsApp's Business API. This follows the official WhatsApp Business Encryption specifications to establish an encrypted GraphQL-powered data exchange channel between your business and the WhatsApp consumer client.

How It Works

Encryption Flow

1. Webhook Reception: Receives encrypted data from WhatsApp containing:

   • encrypted_flow_data: The AES-encrypted payload
   • encrypted_aes_key: The RSA-encrypted AES key
   • initial_vector: Initialization vector for AES decryption

2. Decryption Process:

   • The workflow decrypts the AES key using an RSA private key
   • Then uses this AES key to decrypt the payload data
   • The inverted IV is used for response encryption

3. Data Processing:

   • The workflow parses the decrypted JSON data
   • Routes requests based on the screen parameter.

4. Response Generation:

   • Generates appropriate response data based on the request type
   • Encrypts the response using the same AES key and inverted IV
   • Returns the base64-encoded encrypted response

Key Components

• Webhook Endpoint: Entry point for encrypted WhatsApp requests
• Decryption Pipeline: RSA and AES decryption components
• Business Logic Router: Screen-based routing for different functionality
• Encryption Pipeline: Secure response encryption

How to Use

1. Deploy the Workflow:

   • Import the workflow JSON into your n8n instance

2. Set Up WhatsApp Integration:

   • Configure your WhatsApp Business API to send requests to your n8n webhook URL
   • Ensure your WhatsApp integration is set up to encrypt data using the public key pair of the private key used in this workflow

3. Test the Flow:

   • Send an encrypted test message from WhatsApp to verify connectivity
   • Check if appointment data is being retrieved correctly
   • Validate that seat selection is functioning as expected

4. Production Use:

   • Monitor the workflow performance in production
   • Set up error notification if needed

Requirements

Authentication Keys

RSA Private Key: Required for decrypting the AES key (included in the workflow)
WhatsApp Business Public Key: Must be registered with the WhatsApp Business API
PostgreSQL Credentials: For accessing appointment data from the database

WhatsApp Business Encryption Setup
As specified in the WhatsApp Business Encryption documentation:

Generate a 2048-bit RSA Key Pair:

The private key remains with your business (used in this workflow)
The public key is shared with WhatsApp

Register the Public Key with WhatsApp:

Use the WhatsApp Cloud API to register your public key
Set up the public key using the /v17.0/{WhatsApp-Business-Account-ID}/whatsapp_business_encryption endpoint

Key Registration API Call:
POST /v17.0/{WhatsApp-Business-Account-ID}/whatsapp_business_encryption
{
"business_public_key": "YOUR_PUBLIC_KEY"
}

Verification:

Verify your public key is registered using a GET request to the same endpoint
Ensure the key status is "active"