private function baseString($url, $method, $parameters)
	{
		// Sort the parameters alphabetically
		uksort($parameters, 'strcmp');

		// Encode parameters.
		foreach ($parameters as $key => $value)
		{
			$key = $this->safeEncode($key);

			if (\is_array($value))
			{
				foreach ($value as $k => $v)
				{
					$v    = $this->safeEncode($v);
					$kv[] = "{$key}={$v}";
				}
			}
			else
			{
				$value = $this->safeEncode($value);
				$kv[]  = "{$key}={$value}";
			}
		}

		// Form the parameter string.
		$params = implode('&', $kv);

		// Signature base string elements.
		$base = array(
			$method,
			$url,
			$params,
		);

		// Return the base string.
		return implode('&', $this->safeEncode($base));
	}