* @return false|array
	 */
	protected function prepare_key_download() {

		$key_id       = llms_filter_input( INPUT_GET, 'id', FILTER_SANITIZE_NUMBER_INT );
		$consumer_key = llms_filter_input_sanitize_string( INPUT_GET, 'ck' );

		// return if missing required fields.
		if ( ! $key_id || ! $consumer_key ) {
			return false;
		}

		// return if key doesn't exist.
		$key = LLMS_REST_API()->keys()->get( $key_id );
		if ( ! $key ) {
			return false;
		}

		// validate the decoded consumer key looks like the stored truncated key.
		$consumer_key = base64_decode( $consumer_key ); //phpcs:disable WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode -- This is benign usage.
		if ( substr( $consumer_key, -7 ) !== $key->get( 'truncated_key' ) ) {
			return false;
		}

		return array(
			'fn' => sanitize_file_name( $key->get( 'description' ) ) . '.txt',
			'ck' => $consumer_key,
			'cs' => $key->get( 'consumer_secret' ),
		);