SPEECH SIGNAL CRYPTOGRAPHY USING WPT

Ziad Alqadi,Holwa Fayeq Taha

doi:10.29121/ijetmr.v7.i7.2020.727

Abstract

Digital speech signal is one of the most important types of data used due to the large number of computerized applications that are needed for mankind. Some computerized applications that use digital signals need a high level of security to protect the signal, and to turn it into a vague and incomprehensible signal to any third party, and that is why we have to seek a secure method of cryptography to protect the speech signal. In this research paper we will introduce a method based wavelet packet tree decomposition and reconstruction to generate an encrypted speech, the method will reorder the original speech using a secret number of decomposition levels, the obtained wavelet decomposition sizes will be used to form a speech segments, which must be rearranged in a secret order to get the encrypted speech, the introduced method will be implemented and evaluated to prove the security issues.

Highlights

The digital signal [3], [4], [5] such as sound [1] and digital image [2], [6], [7] is considered one of the most important types of data currently used and one of the most widely circulated data [8], [9], [10]
By selecting the decomposition level we can obtain a set of approximations and details (C in the figure) with a specified length of each (L in the figure), these components can be used to divide a speech signal into segment with a defined length, these segments can be rearranged in order to generate an encrypted speech signal, figure 3 shows an example of signal decomposition using Wavelet packet tree method (WPT): Figure 3: Speech signal decomposition example
The proposed method of encryption-decryption is based on WPT decomposition, and the encryption phase as shown in figure 4 can be implemented applying the following steps: 1) Get the original speech signal

Summary

INTRODUCTION

The digital signal [3], [4], [5] such as sound [1] and digital image [2], [6], [7] is considered one of the most important types of data currently used and one of the most widely circulated data [8], [9], [10]. The process of data encryption [17], [18] is only the process of destroying the original data so that this data becomes distorted and incomprehensible to any third party who is not authorized [19], [20] and this process is usually carried out by carrying out specific processing operations on the original data and by using a secret key (as shown in figure 1) [21], [22] that is known only by the sender and its recipient. As for the decryption process, it is executed on the encrypted data using the secret key and the specific processing operations to obtain data identical to the original without losing or losing any part of the information [23], [24], [25]. By selecting the decomposition level we can obtain a set of approximations and details (C in the figure) with a specified length of each (L in the figure), these components can be used to divide a speech signal into segment with a defined length, these segments can be rearranged in order to generate an encrypted speech signal, figure 3 shows an example of signal decomposition using WPT:

THE PROPOSED METHOD

IMPLEMENTATION AND EXPERIMENTAL RESULTS

CONCLUSION