# File lib/facebook_desktop_session.rb, line 108
    def signature(params)
      # choose the proper secret
      signatureSecret = nil
      unless (params[:method] == "facebook.auth.getSession" or params[:method] == "facebook.auth.createToken")
        signatureSecret = @session_secret
      else
        signatureSecret = @api_secret
      end
    
      # sign the parameters with that secret
      return signature_helper(params, signatureSecret)
    end