MessageSerializer

hash.rb

class Hash
  def symbolize_keys
    inject({}) do |result, (key, value)|
      new_key         = case key
                          when String then
                            key.to_sym
                          else
                            key
                        end
      new_value       = case value
                          when Hash then
                            value.symbolize_keys
                          else
                            value
                        end
      result[new_key] = new_value
      result
    end
  end
end

message_serializer.rb

require 'securerandom'
require 'base64'
require 'json'

class MessageSerializer
  class << self
    def dump(hash)
      encrypt hash.to_json
    end

    def load(hash)
      JSON.parse(decrypt hash).symbolize_keys
    end

    private
    def encrypt(message)
      encode64 scramble(message, __method__)
    end

    def decrypt(message)
      scramble decode64(message), __method__
    end

    def scramble(message, mode)
      cipher     = cipher mode
      cipher.key = key
      cipher.update(message) << cipher.final
    end

    def cipher(mode)
      OpenSSL::Cipher::AES256.new(:CBC).send mode
    end

    def key
      @key ||= OpenSSL::Digest::SHA256.digest secret
    end

    def secret
      ENV['CPIHER_KEY'] || '3ac956d2'
    end

    def encode64(message)
      Base64.urlsafe_encode64 message
    end

    def decode64(message)
      Base64.urlsafe_decode64 message
    end
  end
end