A Voice Hiding Method Based upon Analog Modulation Technique

[[abstract]]在這篇論文中，我們提出ㄧ個運用類比調變技術隱匿音頻訊息之方法。 由聲音學可知，我們人類的一些聽覺缺陷(特性)；其中一個特性是，當聲音訊號太高頻的時候，我們人的耳朵是沒辦法聽到的(人類約可聽到頻率為一萬六Hz以內的聲音)。因此我們利用類比調變技術，將我們的秘密訊號調變至頻率高的位置，以達到保護訊號的工作。我們方法的一個好處是：不容易被別人察覺我們有秘密的訊號隱藏著，因此使得我們的方法對於訊號保密有不錯的功效。無論如何，當合法的接收者收到我們處理過的加密訊號，他將有能力用我們解密的方法，獲得與我們的秘密訊號相近的訊號，並且得知該訊息。[[abstract]]In this thesis, we propose a voice hiding method based upon analog modulation technique. According to some characteristics (drawbacks) of human hearing system, we know that humans can not hear the speech signal of high frequency (most adults are unable to hear the signals of above 16 kHz). Therefore, we exploit the analog modulation technique to modulate every secret message into high frequency to hide the secret messages. One advantage of our method is that illegal receivers would not be conscious that some message is with secret messages. Thus, the protection of our crypto-method is quite good. However, the legal receivers get the processed-signal, he will get approximate secret signal by our decryption method.[[note]]碩