CTwitterInterface::BuildSignature

protected function BuildSignature($sigString)
{
	if(!function_exists("hash_hmac"))
		return null;

	$key = implode('&',
		$this->urlencode(
			array(
				$this->appSecret,
				($this->tokenSecret? $this->tokenSecret : ''),
			)
		)
	);
	return base64_encode(hash_hmac('sha1', $sigString, $key, true));
}