- (NSString *)createUUID
{
  // Create universally unique identifier (object)
  CFUUIDRef uuidObject = CFUUIDCreate(kCFAllocatorDefault);
 
  // Get the string representation of CFUUID object.
  NSString *uuidStr = [(NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuidObject) autorelease];
 
  // If needed, here is how to get a representation in bytes, returned as a structure
  // typedef struct {
  //   UInt8 byte0;
  //   UInt8 byte1;
  //   ...
  //   UInt8 byte15;
  // } CFUUIDBytes;
  CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuidObject);
 
  CFRelease(uuidObject);
 
  return uuidStr;
}