title: C# code for adaptive authentication
body: <p>Is there any C# code/classes/open-source/tools that is recommended for adaptive authentication?</p>
  
  <p>Some functions of our app utilize a Captcha to avoid spamming or inappropriate behavior, which unfortunately also slows down our genuine users. I would like display the Captcha only if certain parameters look 'shady', such as unusual IP address locations, changing IP for the same account name, unusual browser configs (may hint at anonymization service) etc. etc.</p>
  
  <p>I can obviously write code for this, but I assume it's a common enough problem that public resources would exist to help. We currently use the google Catchpa service, and obviously any solution that wraps that would be absolutely ideal.</p>