Spreading-Based Voice Encryption by Means of OVSF Codes

Diego Renza,Estibaliz Martinez,Dora M Ballesteros

doi:10.3390/app10010112

Diego Renza, Estibaliz Martinez + Show 1 more

Open Access

https://doi.org/10.3390/app10010112

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Journal: Applied sciences	Publication Date: Dec 21, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: Military University Nueva Granada

Abstract

This paper presents a new methodology to encrypt voice signals, in such a way that they simulate being a noise signal. The objective is to obtain a signal that does not generate suspicions about its content, while protecting the message. The process is based on the spread and scrambling of the signal through the use of OVSF (orthogonal variable spreading factor) codes. The security of the method is based mainly on the input value used for the randomization phase. From a computational cost point of view, the use of fixed-length codes allows for a shorter retrieval time compared to a similar method based on variable-length codes. Regarding the encrypted signal, its main characteristic is its high entropy (very close to the ideal value). Finally, in the recovery process, a signal identical to the original is obtained.

Highlights

With the advance of technology, the volume of information processed daily has grown exponentially
The proposed encryption scheme for voice signals is based on the spreading of the input signal using OVSF codes, obtaining a signal that will sound like noise
CSF is a 2b × 2b matrix, where each row corresponds to an OVSF code

Summary

Introduction

With the advance of technology, the volume of information processed daily has grown exponentially. The security of the information has become a necessity when transmitting private information. Some authors have proposed new methodologies aimed at providing a level of data security and integrity. The purpose of transmitting information under any secure communication method is to provide a level of privacy over the data, which means limiting access by a third party or unauthorized people [1,2]. In this regard, encryption is a security mechanism used to provide confidentiality and protection to a system, guaranteeing reliability and protection over the information to be transmitted. Different techniques have been implemented based on the codification of voice signals in order to obtain an undecipherable audio signal whose characteristics are totally different with respect to the original one, including security, confidentiality, and integrity aspects [3]

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