FIELD: physics, computer engineering.
SUBSTANCE: invention relates to controlling access to scrambled content during hierarchical encoding. The hierarchical access control method includes: receiving and transmitting to a protective processor second cryptograms (CWi)Ki for i, ranging from 1 to k-1, obtained by encoding control words CW1-CWk-1 using corresponding keys K1-Kk-1, built using at least part of an array formed by data residing in ECMk, and an operational key CEk; decoding the second cryptograms (CWi)Ki, only if access conditions CAk, obtained in the ECMk message, correspond to access rules TA, and without preliminary comparison of access conditions CAi with access rules TA for i, strictly less than k, and, otherwise, blocking decoding of the second cryptograms (CWi)Ki, if access conditions CAk do not correspond to access rules TA.
EFFECT: controlling access to content which is encoded and scrambled on component elements in a hierarchical manner with less computational power compared to existing methods.
11 cl, 8 dwg
