title: How to securely pass the API Key in the HTTP Header?
body: <p>I am building a API suite to connect to our application. Each user will have an unique API key which will be passed in the Header. </p>
  
  <p>I am here to ask, what is the best way to authenticate the user? I donot want the user to pass the API key without any encryption ? </p>
  
  <p>I am passing the API key like this : </p>
  
  <pre><code>$headers['x-axpr-auth'] = '&lt;API-KEY&gt;';
  </code></pre>
  
  <p>Since, I am building the API myself, I have the flexibility to use different encryption/authentication techniques. </p>