code: public AuthResult authenticate(String username, String password, String division) {
          ensureConnection();
          
          if (isAuthenticated()) {
              return new AuthResult("0");
          }
          
          String av = username + ";" + password;
          List<String> results = callRPCList("RGNETBRP AUTH:" + Constants.VERSION, null, connectionParams.getAppid(),
              getLocalName(), "", // This is the pre-authentication token
              ";".equals(av) ? av : Security.encrypt(av, serverCaps.getCipherKey()), getLocalAddress(), division);
          AuthResult authResult = new AuthResult(results.get(0));
          
          if (authResult.status.succeeded()) {
              setPostLoginMessage(results.subList(2, results.size()));
              init(results.get(1));
          }
          
          return authResult;
      }
docs: Request authentication from the server.
  
  @param username User name.
  @param password Password.
  @param division Login division (may be null).
  @return Result of authentication.