title: Creating SHA1 Hash from NSString
body: <p>How can I create a SHA1 from a <code>NSString</code>.</p>
  
  <p>Let's say the NSString is set up as:</p>
  
  <pre><code>NSString *message = @"Message";
  </code></pre>
  
  <p>I can use PHP to create a SHA1 hash with <code>sha($message)</code>. But unfortunately it doesn't work like that within Objective-C.</p>