public function unmaskToken($maskedToken)
	{
		$decoded=base64_decode(strtr($maskedToken,'-_','+/'));
		$length=$this->strlen($decoded)/2;
		// Check if the masked token has an even length.
		if(!is_int($length))
			return '';
		return $this->substr($decoded,$length,$length)^$this->substr($decoded,0,$length);
	}