title: CommonHMAC in Swift
body: <p>I'm trying to create a HMAC SHA-1 hash of a string in Swift but can't figure out how to interact with the APIs as it doesn't seem to be importing the CommonCrypto framework. I've tried various different forms of "import CommonCrypto" and creating a bridging header file but none of it made a difference. </p>
  
  <p>The odd thing is that if I create an Objective-C class, I'm able to interact with APIs without any problems, so this seems to be unique to Swift.</p>
  
  <p>Also if anyone could tell me what the equivalent of <code>uint8_t digest[CC_SHA1_DIGEST_LENGTH]</code> is in Swift I'd be very grateful</p>