A METHOD FOR SECURING A PORTABLE SECURITY MODULE FOR USE WITH A DECODING ELEMENT AND A PORTABLE SECURITY MODULE

摘要

A method for securing a portable security module for use with a decoding element, the portable security module and the decoding element allowing to descramble scrambled audiovisual information are disclosed. The method comprises processing at the portable security module Entitlement Control Messages (ECMs) received at the portable security module to allow the descrambling of the scrambled audiovisual information; analyzing at the portable security module a sequence of ECMs, the sequence of ECMs comprising a new ECM and a previous ECM received at a previous time, the ECMs of the sequence being received at the portable security module at distinct times, the analyzing being performed at the receiving of the new ECM; incrementing an error register upon a determined result of the analyzing, wherein the error register is incremented when the previous ECM and the new ECM do not match; and applying a penalty to the portable security module depending on a value of the error register by introducing a dead time at the processing so as to slow down the processing.