A system for scrambling/descrambling packets of a stream of content, each packet having a must stay clear (MSC) section, the system including an input handler including a receiving module to receive the stream, a characteristic analyzer to analyze the stream in order to determine a data independent characteristic of each packet, and a scrambling /descrambling device operationally associated with the input handler, the scrambling/descrambling device including a receiving module to receive the data independent characteristic for each packet from the input handler, and an Initial Value module to determine an Initial Value for each packet as a function of the data independent characteristic of one of the packets being processed, wherein the scrambling/descrambling device is adapted to scramble and/or descramble the packets based on the Initial Value and a Control Word. Related apparatus and methods are included.