title: How to use the CCHmac() function in iOS
body: <pre><code>CCHmac(CCHmacAlgorithm algorithm, const void *key, size_t keyLength,
         const void *data, size_t dataLength, void *macOut);
  </code></pre>
  
  <ul>
  <li>What will be the key?</li>
  <li>what will be the data?</li>
  <li>what will be the macOut?</li>
  <li><p>For example, I have API:</p>
  
  <pre><code>https://
  somedomain/
  beta/
  men?
  key=[API KEY]&amp;signature=[Signature]}
  </code></pre>
  
  <p>How can I pass API key to CCHmac function and get the signature and make the complete API, e.g.:</p>
  
  <pre><code>https://
  Somedomain/
  beta/
  men?
  key="Abcdefghi12345"&amp;signature=jhfjkshkjfhsdkfhkshdkjfioeoiejafjnanjasbjfs="}
  </code></pre></li>
  </ul>
  
  <p>Can someone provide me good tutorial or sample code for <code>CCHmac</code> function? I looked on the web but I don't find anything.</p>