How to get the hash value from check_box?

I want to get the value "0" (not checked) or "1" (checked) from check_box and save it as hash value. But no value can be saved... paper: nil I created the column "paper" as integer. Can someone help me?

Here is my code:

View:

<div class="formgroup">
  <%= f.label :paper, "Paper_Collection" %>
  <% @paper.each do |key, value| %>
  <div class="checkbox" >
    <%= f.check_box :paper, {checked: false, multiple: true}, value == "1" ? "checked" : "" %><%= key %>
  </div>
  <% end %>
</div>

Controller:

def new
  @box = Box.new
  @paper = {red: 0, blue: 0, yellow: 0, green: 0, black: 0, white: 0}
....
end
def create
  @box = Box.new(box_params)
  @box.user_id = current_user.id
  @paper = {red: 0, blue: 0, yellow: 0, green: 0, black: 0, white: 0}
...
end
private
 def box_params
  params.require(:box).permit(:status, :paper, :cable, reports: [])
 end