# File lib/omniauth/strategies/oauth2/taobao.rb, line 73
      def generate_sign(params)
        # params.sort.collect { |k, v| "#{k}#{v}" }
        str = client_secret + params.sort {|a,b| "#{a[0]}"<=>"#{b[0]}"}.flatten.join + client_secret
        params['sign'] = Digest::MD5.hexdigest(str).upcase!
        params
      end