Guides

Device Fingerprinting

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In the Device Fingerprinting guide, you learned how you can combat piracy of your content by displaying a device-specific watermark on the screen.

In this tutorial, we'll write a very simple Node.js script that calls the API.

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Note

In this screenshot, the resolution and timecode data is part of the video, while the device ID is injected by the device fingerprinting feature. The fingerprint has been styled using the API to match the other text, but is rendered in a completely different way!

Prerequisites

  • Create an API Key for a tenant with senza:messages:send-direct and senza:messages:send-group permissions.
  • Read the guide on Making API Requests to learn how to call the Senza API.

Display Fingerprint API

See the Display Fingerprint page in the API Reference for full details on calling the API.

You can make a POST request to https://api.senza.synamedia.com/tenants/1.1/{tenantId}/displayFingerprint. Include the ID of the tenant corresponding to the one you selected when creating the API key in the URL path.

The body of the request should contain these parameters:

  • textColor: Hexadecimal color code for the text color, i.e. #FFFFFFFF. Note that it takes an eight-character code with RGBA values. For the last two characters, 00 represents transparent and FF is opaque.
  • backgroundColor: Hexadecimal color code for the background color, in the same format.
  • position: Position of the fingerprint display on the screen, which can be one of these strings:
    • top-left, top-center, top-right
    • middle-left, middle-center, middle-right
    • bottom-left, bottom-center, bottom-right
  • duration: Duration in seconds to display the fingerprint on the screen. Duration with 0 turns it off.
  • fontSize: Font size for the fingerprint text.

For example, if you call the API with these parameters, it will display a the fingerprint like in the screenshot above, with 38-point yellow text on a black background. 

{
  "textColor":"#EEE450FF",
  "backgroundColor":"#000000FF",	
  "position":"bottom-center",
  "duration":1200,
  "fontSize":38
}

Script

Here is a very short Node.js script that demonstrates how to call the API.

Start by editing the config.json file with:

  1. your tenant ID
  2. the client ID and client secret you obtained when creating your API key
  3. the body parameters you'd like to use
{
  "tenantId": "your-tenant-id",
  "oauth": {
    "client_id": "your-client-id",
    "client_secret": "your-client-secret",
    "audience": "https://projects.synamedia.com",
    "grant_type": "client_credentials"
  },
  "params": {
    "textColor": "#EEE450FF",
    "backgroundColor":" #000000FF",	
    "position": "bottom-center",
    "duration": 20,
    "fontSize": 38
  }
}

Here is the whole script:

import config from './config.json' with {type: "json"};

async function getAccessToken() {
  let tokenResponse = await fetch("https://auth.synamedia.com/oauth/token", {
  	method: "post",
  	body: JSON.stringify(config.oauth),
  	headers: {"Content-Type": "application/json"}
  });
  let json = await tokenResponse.json();
  return json.access_token;
}

async function displayFingerprint(accessToken, tenantId, params) {
  let res = await fetch(`https://api.senza.synamedia.com/tenants/1.1/${tenantId}/displayFingerprint`, {
  	method: "post",
  	body: JSON.stringify(params),
  	headers: {
      "Content-Type": "application/json",
      "Authorization": "Bearer " + accessToken
    }
  });
  console.log(res.status);
}

(async () => {
  const accessToken = await getAccessToken();
  await displayFingerprint(accessToken, config.tenantId, config.params);
})();

First, the script exchanges the API key for an access token by calling the Auth Token endpoint.

Then, it calls the Display Fingerprint API with the tenant ID in the URL path, the access token in the headers, and the body parameters from the config file.

You don't need to install anything because the script does not depend on any packages. To run the script, call:

node device-fingerprint.js

It will print 200 indicating success. All devices in the tenant will then display the device ID fingerprint.

Examples

You can go for a subtle look:

  "params": {
    "textColor": "#e20074FF",
    "backgroundColor":" #5D3FD3FF",	
    "position": "middle-center",
    "duration": 100,
    "fontSize": 80
  }

Or a not-so-subtle look:

  "params": {
    "textColor": "#e20074FF",
    "backgroundColor":" #5D3FD3FF",	
    "position": "middle-center",
    "duration": 100,
    "fontSize": 80
  }

Updated 3 days ago