本論文主要是在無線區域網路的環境，設計一套具有保密功能的視訊通訊系統來達到即時且安全的多媒體資料傳輸。本文利用橢圓曲線方法來對使用者身份資料及會議金鑰加密，並使用LFSR/ FCSR ASG亂數產生器來實現即時多媒體資訊串流加解密的功能，以達到即時安全傳輸的效果。另外，本文是將影像、語音分離處理，影像使用JPEG壓縮技術；音訊方面則是使用LZO壓縮技術，以有效降低傳輸的資料量，若遇到網路頻寬不足時，本系統可選擇關閉影像傳輸，只維持單純的語音安全通訊。

The goal of this research is aimed at real-time, secure communication in the wireless environment. Elliptic curve cryptography is used to encrypt the user's identity and a session key and a stream cipher based on LFSR/FCSR ASG are developed to process multimedia data in real-time, with secure transmission. Under an uncertainty of bandwidth scenario, video and audio are compressed by JPEG and LZO separately. As a result, the amount of data to be transmitted has been reduced significantly. When the network is extremely congested, this system can be forced to suspend the video stream so that it can maintain secure communication, using audio data only.