This dissertation presents the application of independent component analysis (ICA) and chaos synchronization on secure communications. We reviewed literatures related to chaos and ICA encryptions. The shortages of chaos and ICA encryptions are also pointed out. A modified ICA is proposed to recover signals with precise amplitude and phase. Three new schemes for secure communication are proposed. These schemes utilize ICA and chaos techniques to encrypt a message signal. Using a modified ICA technique, the schemes enable encryption of message signals with white noises. The keys, key space and key selection rules for each scheme are discussed in detail. Security analyses reveal that these schemes are immune to possible attacks including ciphertext only attack, known-plaintext, chosen plaintext/ciphertext attack, filtering attack, etc. Performance analyses are given by three measures including root mean square error, signal to noise ratio and computational times. Results show that the original message signal have been well masked by the key signals in the encrypted signals yet recovered faithfully and efficiently by the present schemes.

本論文提出獨立成份分析與渾沌同步在秘密通訊的應用，文中回顧有關渾沌加密和獨立成份分析加密法相關的文獻，並討論渾沌加密與獨立成份分析加密法的優缺點。進一步我們提出一個修正的獨立成份分析法來準確地回復訊號的振幅與相位。論文中提出三個使用獨立成份分析與/或渾沌同步於秘密通訊的方法。利用修正的獨立成份分析技術，可使用雜訊將原訊息訊號加以加密。論文中詳細討論每個方法的金鑰、金鑰空間及金鑰的選擇法。安全性分析顯示所提之方法免於只知密文攻擊、已知明文攻擊、選擇明文/密文攻擊及濾波攻擊等等。論文中以誤差均方根、訊雜比及計算時間來評估效能分析，結果顯示本論文所提之方法可將原訊息訊號隱藏在密文中並且有效率的解密訊息訊號。

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