| 摘要 |
<p>Key encryption key data used for communication between a key management device (3) and reception devices (4_1 to 4_N) is acquired according to a tree divided into two horizontal layers (A0, A1). In this case, the LSD method is employed as the revocation method of each section (31 [0]) belonging to the horizontal layer (A0). Moreover, the CST method is employed as the revocation method of each section (31 [1]) belonging to the horizontal layer (A1).</p> |
