基于DCT变换的端到端语音加密算法

为了实现语音的端到端安全加密通信，提出了一种新的可通过RPE LTP压缩编码的语音加解密算法。该算法基于DCT变换域，在发送端对语音信号先后进行频域置乱和时域置乱，接收端进行解置乱和重建信号。运算过程限制在实数域，不会涉及相位的估计问题，避免了语音数据的损失。仿真结果表明，加密算法实现了加密的语音信号非噪声化，保持了语音信号的特性，满足通过声码器进行编码的信号输入要求。进一步降低了加密后的语音可懂度，提高了解密后的语音质量和信号重建率。

End to end speech encryption algorithm based on DCT transform

For the realization of the end to end secure encrypted communication of voice,this paper proposes a new voice encryption algorithm,which can penetrate RPE LTP compression encoder. In the sender,the algorithm scrambles with the voice signal in frequency and time domain based on DCT transform domain .In the receiving end, it decrypts and reconstructs the signal. Opreation process is limited in real number domain and does not involve the phase estimation problem,it avoids the loss of voice data.The results show that the encryption algorithm can realize the non noise signal of the encrypted voice,maintains the characteristics of the speech signal, meets the requirements of input signal to penetrate RPE LTP compression encoder.Reduce the encrypted speech intelligibility further, improve the quality of the decrypted voice.