A Four Level Speech Signal Encryption Algorithm

In this paper, we present a novel speech encryption algorithm based on four level of hash based encryption. Our approach integrates a modified time domain scrambling scheme with an amplitude scrambling method which masks the speech signal with algorithmic based noise by specific mixing. In this, we use different algorithm to encrypt the speech signal at different levels i.e. we encrypt the original signal four times using different algorithm at each level. The output of one level makes the input of next level. As a result of this algorithm, the speech signal becomes more and more secure at each level.