title: API Key content encryption
body: <p>I just started experimenting with RESTful APIs.</p>
  
  <p>Generally, two kinds exist: open APIs and private APis for which you need API keys. What exactly are API keys used for? Can they ensure data encryption as well? I am confused because some API providers have 2 sets of keys, one public and another private perhaps pointing towards data and content security as well?</p>
  
  <p>To sum up, if I query the database using a RESTful API and its key, the response that I receive from the database will be secure/encrypted or APIs keys are just used to authenticate source of request?</p>