+ /**
+ * Generate a new keypair for a local user and store in the database.
+ *
+ * Warning: this can be very slow on systems without the GMP module.
+ * Runtimes of 20-30 seconds are not unheard-of.
+ *
+ * @param int $user_id id of local user we're creating a key for
+ */
+ public function generate($user_id)