# File lib/httpclient/auth.rb, line 408
    def get(req)
      return nil unless NTLMEnabled
      target_uri = req.header.request_uri
      domain_uri, param = @challenge.find { |uri, v|
        Util.uri_part_of(target_uri, uri)
      }
      return nil unless param
      user, passwd = Util.hash_find_value(@auth) { |uri, auth_data|
        Util.uri_part_of(target_uri, uri)
      }
      unless user
        user, passwd = @auth_default
      end
      return nil unless user
      state = param[:state]
      authphrase = param[:authphrase]
      case state
      when :init
        t1 = Net::NTLM::Message::Type1.new
        return t1.encode64
      when :response
        t2 = Net::NTLM::Message.decode64(authphrase)
        t3 = t2.response({:user => user, :password => passwd}, @ntlm_opt.dup)
        @challenge.delete(domain_uri)
        return t3.encode64
      end
      nil
    end