No.
Instead, implement the method SPSessionDelegate -session:didGenerateLoginCredentials:forUserName:and save the credentials in NSUserDefaultsor whatever (these credentials are already encrypted and are safe to store in clear text).
, , , SPLoginViewController SPSession attemptLoginWithUserName:existingCredential:rememberCredentials:. , , - , .
, rememberCredentials: attemptLoginWithStoredCredentials: .