由於近年來，與多媒體相關的廣泛應用備受各界需要，因此安全性的議題與考量便格外的重要。而這之中使用MHT以及REC/RPB之加密策略，便是能夠同時兼顧安全性和高效能的兩種加密方法。它們天生具有之低加密成本特性使得它的發展非常值得期待。 而在本論文中，將提出讓MHT與REC/RPB所加密之密文串在實際網路傳輸時，能有效抑制加密所造成之錯誤擴散範圍，讓密文串在遭遇傳輸錯誤與封包遺失時，具有一定程度的錯誤抵抗能力，使得原加密策略可使用於著重即時處理之視訊資料的改良方法。雖然它會增加儲存臨時金鑰的暫存空間要求，並且對時間效能與安全性有一定程度的影響，但仍能保持格式相容、及REC本身不因金鑰的不同而影響壓縮率的特性。並能因應實際即時視訊傳輸時，能夠不需解碼已超過時間之封包，就能正確解密目前時間點之圖像。因而這項研究，將有助於MHT與REC/RPB能實際應用於即時與同步處理方面的發展上。 The application for multimedia is very valued in recent years, included multi- media security. In this respect, MHT (Multiple Huffman Tables) and REC (Randomize Entropy Coding) / RPB (Rotation in Partition Bit streams) encryption schemes, is a good scheme that can satisfy security and efficiency than other method. In this paper, we propose the enhanced strategy that can reduce the error propagation range in network transmission for encrypted cipher by MHT or REC/RPB. Although, it increase the storage space for KHS register, and will effect the security and efficiency, but it isn''t serious. And this strategy can compatible for real-time application for throw away the timeout packet. Therefore, this approach will conduce to the real-time multimedia encryption application for MHT and REC/RPB.
