Patent ID: 8458454

Claim:
A conditional access apparatus capable of decrypting a first encrypted key information that meets a first predetermined filter condition, but incapable of decrypting a second encrypted key information that meets a second predetermined filter condition, said conditional access apparatus comprising: a hardware processor-based filtering unit for: receiving encrypted media data to output said media data, receiving encrypted key information, determining whether said received key information meets the first or the second predetermined filter condition, and when said received key information meets the first or the second predetermined filter condition, outputting said received key information; a hardware processor-based key information decrypting unit for: setting said first predetermined filter condition to said filtering unit, and decrypting the key information outputted from said filtering unit when the outputted key information is the first encrypted key information that meets the first predetermined filter condition, a hardware processor-based media data decrypting unit for decrypting the media data outputted from said filter unit by using the key information decrypted by said key information decrypting unit; and a hardware processor-based key information informing unit for: receiving the second predetermined filter condition from another conditional access apparatus to set said received second predetermined filter condition to said filtering unit, and when the outputted key information is the second encrypted key information that meets said second predetermined filter condition and is thus outputted from said filtering unit, sending the outputted key information to the other conditional access apparatus.