Information Hiding in Speech Signals for Secure Communication (eBook)

Zhijun Wu (Autor)

eBook Download: EPUB

2014 | 1. Auflage
200 Seiten
Elsevier Science (Verlag)
9780128014813 (ISBN)

Infos

In the digital world, the need to protect communications increases every day. While traditional digital encryption methods are useful, there are many other options for hiding your information. Information Hiding in Speech Signals for Secure Communication provides a number of methods to hide secret speech information using a variety of digital speech coding standards. Professor Zhijun Wu has conducted years of research in the field of speech information hiding, and brings his state-of-the-art techniques to readers of this book, including a mathematical model for information hiding, the core concepts of secure speech communication, the ABS-based information hiding algorithm, and much more. This book shows how to implement a secure speech communication system, including applications to various network security states. Readers will find information hiding algorithms and techniques (embedding and extracting) that are capable of withstanding the advanced forms of attack. The book presents concepts and applications for all of the most widely used speech coding standards, including G.711, G.721, G.728, G.729 and GSM, along with corresponding hiding and extraction algorithms. Readers will also learn how to use a speech covert communication system over an IP network as well as a speech secure communication system applied in PSTN. - Presents information hiding theory and the mathematical model used for information hiding in speech. - Provides a number of methods to hide secret speech information using the most common digital speech coding standards. - A combination of practice and theory enables programmers and system designers not only to implement tried and true encryption procedures, but also to consider probable future developments in their designs.

Professor Zhijun Wu achieved his post-doctoral work of Information security in July 2005 at Tsinghua University. He is currently a professor and doctoral tutor in the Civil Aviation University of China, and he is an expert of network information security in The Chinese Institute of Electronics. His research interests are in the field of networking and information security, and security protocol analysis and design.

Textauszug

Chapter 1

Introduction

Abstract

This chapter gives a general introduction to the background of secure communication based on information hiding, the application of information hiding, and speech coding technology. The basic definitions and related concepts in the realm of speech information hiding are introduced. The fundamentals will help readers to comprehend the new technology of information hiding. To help readers better understand the development of the research contents of this book, related works are analyzed to show other researchers’ achievements. A comparative analysis of the existing information hiding methods is given, as well as simple summaries of the principles and working processes for the five kinds of existing methods. Finally, the organization of this book is presented.

Keywords

analog scrambling

analysis-by-synthesis (ABS)

chaotic secure communication

decryption

digitized encryption

encryption

information hiding

LPC-IH-FS

MES-BD

minimum mean square error (MES)

Public Switched Telephone Network (PSTN)

steganography

Voice over Internet Protocol (VoIP)

Information communication is one of the most significant features of an information society. As an important part of information communication, secure communication protects state secrets, commercial secrets, and personal privacy, which is crucial for the nation, society, and individuals. Human beings are living in an information society, and communication security and confidentiality are used not only for military purposes, but also for public life, such as network voice communication, mobile communication, electronic payment, and mobile banking on the Internet [1].

There are many kinds of methods for secure communication over networks, although the available methods have different levels of shortcomings [2]. New approaches of secure speech communication are proposed to transmit security information via Voice over Internet Protocol (VoIP) and Public Switched Telephone Network (PSTN) based on the techniques of information hiding discussed in this chapter.

1.1. Background

With the development of network communication technology, speech communication technology has seen a gradual transition to VoIP communication from the original PSTN network communication [3]. At present, the speech communication network has become a hotspot in international and domestic telecommunications development. More and more speech services through networks are realized.

As we know, network-based threats have become more sophisticated, and PSTN and VoIP calls are vulnerable to threats such as session hijacking and man-in-the-middle attacks [2]. Without proper protective measures, attackers could intercept a PSTN or VoIP call and modify the call parameters or addresses (numbers). Even without modifying PSTN numbers or VoIP packets, attackers may be able to eavesdrop on telephone conversations being carried over a PSTN or VoIP network. If VoIP packets are traveling unprotected over the Internet, the attackers have the opportunity to access the information that these packets carry [4–7].

With a standard PSTN or VoIP connection, intercepting conversations requires physical access to telephone lines or access to the private branch exchange (PBX) and switch or router. Speech or data networks, which typically use the public Internet and the TCP/IP protocol stack, need safeguards to protect data security and personal privacy. In this context, the research of speech secure communication is particularly important [8].

1.1.1. Progress in Secure Communication

The traditional speech secure communication technology mainly adopts the methods of Analog Scrambling [9,10] and Digitized Encryption [11,12]. Analog Scrambling is performed by segmenting and then scrambling the speech signals in the frequency domain, time domain, or both domains at the same time in order to change the intelligible speech signals into unintelligible signals. In Digitized Encryption, the speech signal is digitalized and then encrypted. Both of these traditional approaches rely on the transformation of speech signals themselves and cryptographic strength to protect the security communication of secret information. In recent decades, cryptographic strength has continuously improved. By contrast, the development of speech secure communication systems has been slow. The encryption system of Analog Scrambling has poor security performance, but with the development of voice signal digital technology, Digitized Encryption is widely used in speech secure communication [13,14].

At present, there are many successful encryption algorithms in modern cryptography technology, and their confidentiality is extremely high. So far, the most successful method of secure communication is implemented by data encryption, which has a certain degree of security and is easy to implement. But this method has inherent shortcomings [15,16].

First, most of the current encryption algorithms are designed through specific calculation procedures. The strength of encryption algorithms depends on the computing capacity of the computer in use, and the improvement in the rate of undecipherable passwords relies on increasing the length of the key. With the rapid growth of the computing power of computers, password security is always faced with new challenges.

Second, the approach transforms plain text into cipher text by using an encryption algorithm, and then the cipher text is transferred to the open channel. The encrypted data stream is almost random and meaningless gibberish, implying the encrypted information is important and secret, and attracts attackers’ attention. By monitoring the communication channel, attackers can easily identify the encrypted information. Once gibberish is intercepted, the target of the attack will be found. Various kinds of attack methods can be used for cryptanalysis.

Third, in the case of a small amount of secret information exposure, attackers can gain valuable information by analyzing the characteristics of disclosure information and tracing the content of secret information, even though attackers cannot decode the messages to gain the entire secret content.

The traditional secure telephony based on an encryption system has the same drawbacks [17]. The transferred speech information is hidden in the cipher text. For the eavesdropper, the intercepted information has a high degree of ambiguity, or it can be seen as a kind of interference or noise. Undoubtedly, the communication performance of such a secure communication system can be designed perfectly, but its security performance might not be optimal. Once the secure communication lines were monitored and detected by eavesdroppers, two actions the eavesdroppers may take are:

1. Intercepting secret information from the communication channel carefully and deciphering the information meticulously.

2. Destroying the secure communication line and preventing the transfer of confidential information.

Moreover, the encryption method of the traditional secure telephone is in the time domain or frequency domain, which has two shortcomings:

1. The encryption algorithms and methods are limited, and most of them are based on the analog signal. Encrypted information is easily detected and destroyed.

2. The process of encryption and decryption may lead to different degrees of decline in the quality of the original speech signal.

In addition, a relatively new type of secure communication is chaotic secure communication [18,19]. This approach mainly makes use of the chaos system’s sensitivity to the initial state and parameter dependence to protect the security of confidential information communication. Although chaotic secure communication has been a breakthrough in theoretical and experimental studies, there are still more practical application issues left, and many practical problems such as system synchronization need to be solved [20].

Whenever multimedia data—for example, speech—are transmitted via a network, they need to be protected from manipulation, forgery, and theft. More elaborate attacks demand more sophisticated security technologies, which have to be optimized for the particular requirements of each application scenario. A newly developed technique of information security, information hiding, breaks the traditional cryptology thought concepts. Information hiding technology carefully examines information security from a new perspective [21]. Traditional secure communication approaches cannot satisfy the current security requirements, because the garbled bits are likely to attract attention or even attacks from others. It is imperative to introduce a new mechanism for secure communication, which is why we address this issue. Compared with traditional secure communication and chaotic secure communication, secure communication based on information hiding technology has several distinctive characteristics for secure communication. The most important characteristics are univocal and continuous plain text speech signals that are transmitted on the communication line, so secure communication will be more covert and safer [22].

Traditional secure communication depends mainly on the strength of encryption algorithms. However, with the advent of the...

Produkt-Details

• Erscheint lt. Verlag: 27.8.2014
• Sprache: englisch
• Themenwelt: Informatik ► Netzwerke ► Sicherheit / Firewall
• Themenwelt: Informatik ► Theorie / Studium ► Kryptologie
• Themenwelt: Naturwissenschaften
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• ISBN-13: 9780128014813 / 9780128014813