1xml.instruct!
 2xml.Item ID: id, xmlns: 'https://www.example.org/item#' do
 3  signature_for reference_id: id, xml: xml
 4  xml.Encrypted xmlns: 'https://www.example.org/item#' do
 5    encrypt_data_for xml: xml do |xml|
 6      xml.EncryptMe do
 7        xml.Secret "secret"
 8      end
 9    end
10  end
11end