Demonstrates how one can set own cypher for encrypting file with carrierwave_securefile

_form.html.erb

<%= form_for @book, :html => {:multipart => true} do |f| %>
  <% if @book.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@book.errors.count, "error") %> prohibited this book from being saved:</h2>
 
      <ul>
      <% @book.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
 
  <div class="field">
    <%= f.label :cypher, t(:encrypt_your_file_with_the_following_cypher) %><br />
    <%= f.text_field :cypher %>
  </div>
 
 
  <div class="field">
    <%= f.label :file %><br />
    <%= f.file_field :file %>
  </div>
 
  
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

book.rb

class Book < ActiveRecord::Base
  attr_accessible :expiration, :cypher, :file, :user_id, :asset_id
 
  mount_uploader :file, BookUploader
 
  validates :file, :presence => true
 
  def url
    file
  end
 
end

books_controller.rb

class BooksController < ApplicationController
  .
  .
  .
  # GET /books/new
  # GET /books/new.json
  def new
    @book = Book.new
 
    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @book }
    end
  end
  
  .
  .
  .
end