| 摘要 |
<p>A streaming system for encrypting a compressed image data and distributing it via network by a predetermined transport protocol. A streaming server used in this system performs encryption of each encryption block size starting at the head of a GOP and does not perform encryption of the trailing data not satisfying the encryption block size. The encrypted stream data is transmitted to a client terminal on RTP packet basis. Here, a part of a preceding and subsequent stream data is stored in the extended area of the RTP header so that the size of the stream data transmitted on RTP packet basis is the encryption block size multiplied by an integer. Furthermore, size information on the preceding data and/or the subsequent data added is also stored in the extended area. This streaming server can suppress increase of the size caused by encryption and support both of real-time reproduction and download reproduction without performing re-encryption.</p> |
