Apparatus and method for encrypting MPEG packets

摘要

A method of encrypting clear payload data to form encrypted payload data uses a block cipher, the block cipher being characterized by a predetermined block length. The method includes a step of parsing (7) and first and second steps of encrypting (8). The step of parsing parses (7) the clear payload data into at least one full clear block. Each full clear block is characterized by the predetermined block length. The residual block is characterized by a residual block length, the residual block length being less than the predetermined block length. The step of parsing further parses (7) the last full clear block into a first part and a second part, the second part being characterized by a length equaling a difference between the predetermined block length and the residual block length.