| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a data transmitting device, a data receiving device, and a data transmitting and receiving system, capable of safely transmitting the copyright-protected content in an Internet environment. <P>SOLUTION: The data receiving device receives video-sound data, whose copying is limited, from the data transmitting device in accordance with an Internet protocol. The data receiving device includes: a hop-number measuring part 1205 that measures the number of hops in a path up to the data transmitting device; a TTL determining part 1206 for determining an initial value of a TTL indicating a lifetime of an authentication and key exchange (AKE) packet on the basis of the measured number of hops; a TTL notifying part 1207 for transmitting a packet, in which the determined initial value is included in a payload, to the data transmitting device; and an AKE part 1204 for executing authentication of the data transmitting device and key exchange by using an AKE packet in which the determined initial value is set in a TTL field. <P>COPYRIGHT: (C)2010,JPO&INPIT |
