Speech Encryption Using Stream Cipher

In this work, we have realized an efficient implementation of stream cipher algorithm for speech data encryption and decryption. The design consists of a 128-bit non linear feedback shift register (NLFSR), a 128-bit linear feedback shift register (LFSR) and a Boolean function. First of all three speeches were recorded from different speakers and were saved as wav file format. The developed program is used to transform the original speech data wav file into positive data, and then transform the positive data into positive digital data file. Finally, we use our implemented program to encrypt and decrypt the speech data. The proposed scheme is compared to a similar one of Grain-128. The results show that the proposed scheme is secure and the encrypted speech was very different than the original speech and no significant information on the original speech could be retrieved. Thus, the results given by the proposed scheme are better than the results given by Grain-128.