controller.rb

class SurveyTransController < ApplicationController
  skip_before_filter :authenticate_user!
  layout "survey"

  def survey
  end

  def password_confirmation
    # if params[:password_confirmation].present? && params[:survey_id].present?
        @survey = Survey.find_by_id(params[:survey_id])
        if @survey.present? && @survey.password == params[:password_confirmation]
          session[:current_survey_id] = @survey.id
          redirect_to :survey_form_section
        else
          flash[:notice] = "Datos incorrectos. Favor verifique sus datos."
          redirect_to :survey
        end
    # else
    #   flash[:notice] = "No pueden estar vacios."
    #   redirect_to :survey
    # end
  end

  def survey_form_section
   unless session[:current_survey_id].nil?
    @survey = Survey.find_by_id(session[:current_survey_id])
    @project= @survey.project

    # despues de completar el form
    # redirect_to :survey_form
   else
    redirect_to :survey,
      notice: 'No tiene acceso a esta section. Favor entrar credenciales.'
   end
  end

  def survey_form
    unless session[:current_survey_id].nil?
      @survey = Survey.find_by_id(session[:current_survey_id])
      @anwser = @survey.anwsers.new(answer_params)
      @anwser.section_id = params[:section]
    else
    redirect_to :survey,
      notice: 'No tiene acceso a esta section. Favor entrar credenciales.'
    end
  end

  def survey_proccess
  end

  def survey_finish
  end

  private

    def answer_params
      params.require(:answer).permit()
    end
end   

routes.rb

    get '/survey', to: 'survey_trans#survey', as: :survey
    get '/password_confirmation', to: 'survey_trans#password_confirmation', as: :password_confirmation
    get '/survey_form_section', to: 'survey_trans#survey_form_section', as: :survey_form_section
    get '/survey_form', to: 'survey_trans#survey_form'
    post '/survey_form', to: 'survey_trans#survey_form'
    get '/survey_finish', to: 'survey_trans#survey_finish', as: :survey_finish

view_form.html.erb

<div class="well profile box col-lg-5 col-lg-offset-3">
  <div class="row">
    <div class="col-md-12">

<h1>Contraseña de Confirmación</h1>
<hr />
<%= form_tag({controller: "survey_trans", action: "password_confirmation"}, {method: :get}) do %>
    <div class="form-group">
      <%= text_field_tag :survey_id,nil, class: "form-control", placeholder: "Encuesta",maxlength: 10 %>
      <span class="help-block">"Número de encuesta".</span>
    </div>
    <div class="form-group">
      <%= password_field_tag :password_confirmation,nil, class: "form-control", placeholder: "contraseña",maxlength: 10 %>
      <span class="help-block">"contraseña para poder llenar encuesta".</span>
    </div>
    <button class="btn btn-success ladda-button" data-style="zoom-out" type="submit">
      <span class="ladda-label">Confirmar</span>
      <span class="ladda-spinner"></span>
    </button>
    <%=link_to "Form Section", survey_form_section_path, class: "btn btn-warning"%>

<% end %>
  </div>
 </div>
</div>