Some Aspects for Enhancement of Security in Noisy Environment

To escape eavesdropping, speech scrambling techniques are employed to scramble clear speech into unintelligible signals. Analog scramblers are intended for use in applications where the level of security is not critical and hardware modifications are prohibitively expensive. Lower the correlation between the speech samples to reduce the residual intelligibility of the speech signal. The use of a wide set of kasami sequences to improve security in a speech encryption system is discussed. The speech signal is separated into segments, and the polynomial is created using a chaotic map. Encryption using chaotic map is much better than traditional encryption methods. We are producing a large set of kasami sequences using this polynomial. Using this sequence as a key, the speech signal is encrypted using the AES-128 bit technique. The evaluation is carried out in terms of noise attack. The system's security is determined by the number of PN sequences included in the coding set. Also, the residual intelligibility is very low if each sample of the speech signal is encrypted with a different sequence rather than the same sequence for each sample, hence the signal is better encrypted if the code set comprises a larger number of sequences.