CONTENT DATA, TRANSMITTER APPARATUS, RECEIVER APPARATUS AND DECRYPTING METHOD

摘要

A transmitter apparatus (100) comprises an initialization vector generating part (110) that generates an initialization vector (IV1-IV5) which is used for encrypting stream data by use of a stream cryptography system and which is changed at every initializing interval specified by a stream cryptography module; an initialized packet generating part (140) that generates an initialized packet (IP) which includes an initialization vector to be used in encrypting stream data immediately after the initialized packet and which also includes another initialization vector to be used in encrypting stream data other than the stream data immediately after the initialized packet; an encrypting part (120) that uses the generated initialization vector to initialize a stream cryptography module and that further uses the initialized stream cryptography module to encrypt the stream data immediately after the initialization vector; an encrypted packet generating part (130) that generates an encrypted packet (EP) including the encrypted stream cryptography data; and a transmitting part (150) that transmits, by use of broadcast/multicast, the initialized packet (IP) and encrypted packet (EP).