摘要 |
The present invention is directed to a streaming system for encrypting compression-encoded image data to distribute it via network of a predetermined transport protocol, and a streaming server used in this system transmits, to a client terminal, on the RTP packet basis, stream data encrypted so that encryption is performed every encryption block size from the leading portion of each GOP without encrypting the last data having less than encryption block size. In this instance, portions of prior and/or posterior stream data are stored into an extended area of RTP header so that size of stream data transmitted every RTP packet is integral multiple of encryption block size. Further, size information of added prior additional data and/or posterior additional data are also stored into the extended area. This streaming server suppresses increase in size by encryption to have ability to support both real time production and down-load reproduction without replacement of encryption.
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