title: Issue using CCCrypt (CommonCrypt) in Swift
body: <p>I am porting a working Objective-C Category (NSData+AESCrypt.m) to Swift and I have found an issue working with the pointers.  The code for the encrypting part in Swift compiles correctly, but generates a runtime EXEC_BAD_ACCES error.</p>
  
  <p>The code I have so far is (I tried to dissect the code as much as possible) :  </p>
  
  <pre><code>let key = "123456789012345678901234567890120"
  let keyLength = UInt(kCCKeySizeAES256 + 1)
  let keyPointer = strdup(key)    // Convert key to &lt;UnsafeMutablePointer&lt;Int8&gt;
  
  let message = "Don´t try to read this text. Top Secret Stuff"
  let data = (message as NSString).dataUsingEncoding(NSUTF8StringEncoding)
  let dataBytes = data?.bytes
  let length = data?.length
  let dataLength = UInt(length!)
  let dataPointer = UnsafePointer&lt;UInt8&gt;(dataBytes!)
  
  let operation: CCOperation = UInt32(kCCEncrypt)
  let algoritm: CCAlgorithm = UInt32(kCCAlgorithmAES128)
  let options: CCOptions = UInt32(kCCOptionECBMode + kCCOptionPKCS7Padding)
  
  let cryptBufferSize = UInt(dataLength + kCCBlockSizeAES128)
  var cryptBuffer = [UInt8](count: Int(cryptBufferSize), repeatedValue: 0)
  var cryptBufferPointer = UnsafeMutablePointer&lt;UInt8&gt;(cryptBuffer)
  
  var numBytesEncrypted = UnsafeMutablePointer&lt;UInt&gt;()
  
  var cryptStatus = CCCrypt(operation, algoritm, options, keyPointer, keyLength, nil, dataPointer, dataLength, cryptBufferPointer, cryptBufferSize, numBytesEncrypted)
  
  if UInt32(cryptStatus) == UInt32(kCCSuccess) {
      let size = NSInteger(cryptBufferSize)
      let encryptedData = NSData(bytes: cryptBufferPointer, length: size)
      let encryptedString = NSString(data: encryptedData, encoding: NSUTF8StringEncoding)
      println("Encrypted String = \(encryptedString)") // EXEC_BAD_ACCESS error
  } else {
      println("Error: \(cryptStatus)")
  }
  </code></pre>
  
  <p>The encryptedData object shows the following info: </p>
  
  <pre><code>&lt;279c2d0f d3ce2200 0dc10cc1 9df46e76 cb26f423 7c9bde76 f9d8d0e2 632acef9 74fb0614 4717422b 684d1889 e3ce882c 00000000 00000000 00000000 0000&gt;
  </code></pre>
  
  <p>But the encryptedString shows <code>0x0000000000</code> in the debugger, and trying to <code>println()</code> it generates the EXEC_BAD_ACCESS error</p>
  
  <p>Any idea what is missing?</p>
  
  <p>Rgds.... </p>