Cryptography and Network Security

Starting with the historical facts behind the concept of information, which led to the creation of computer networks, Internet of things and cryptocurrencies, the book then arrives at the main definitions of cryptography and network security, the protocols that keep the systems running and the cybercrimes that could disrupt the systems. The basics of information theory, how to measure information, and the information associated with a source are discussed. Source codes are presented, along with the concepts of information transmission, joint information, conditional entropy, mutual information and channel capacity. Computer networks are discussed, including the main protocols and network architectures, and the important TCP/IP protocol. Network security, a topic intrinsically connected to computer networks and the Internet, is presented, along with information about basic hacker attacks, alternatives to prevent attacks, data protection and secure protocols. The information theoretical aspects of cryptography are described including the hash function. Appendices include a review of probability theory, a discussion of cryptoalgorithms and cryptosystems, and a glossary of information security terms. Illustrations and graphics help the reader understand the theory. This book provides a comprehensive introduction to the foundations of cryptography and network security. As well as a thorough presentation of the evolution of the topic the book includes information about basic hacker attacks, alternatives to prevent attacks, ways to increase data protection and how to set up and implement secure protocols. Front Cover 1 Cryptography and Network Security 4 Dedication 6 Contents 8 Preface 16 Acknowledgements 18 List of Figures 20 List of Tables 24 1 Introduction 26 1.1 Information on the Network 28 1.2 The Internet of Things 29 1.3 Network Security 31 1.4 Network Encryption 32 1.5 Electronic Voting 33 1.6 Security with Biometrics 35 1.7 How to Understand Recognition 37 1.8 Blockchain and Cryptocurrency 38 1.8.1 Enterprises Can Profit from Blockchain 38 1.8.2 The Cryptocurrency Frenzy 39 2 Main Definitions 44 2.1 Criteria for a Security System 44 2.2 Security Aspects to Consider 45 2.3 Malicious Codes 47 2.3.1 Virus 48 2.3.2 Worms 49 2.3.3 Robots 50 2.3.4 Spy Programs 51 2.3.5 Backdoor Program 52 2.3.6 Trojan Horse 52 2.3.7 Rootkit 53 2.4 Internet Scams 54 2.4.1 Identity Theft 55 2.4.2 Resource Anticipation Fraud 55 2.4.3 Phishing 55 2.4.4 Pharming 56 2.4.5 E-commerce Scams 56 2.4.6 Hoax 57 2.5 Internet Attacks 58 2.5.1 Vulnerability Exploitation 59 2.5.2 Network Scan 59 2.5.3 Fake E-mail Address 59 2.5.4 Traffic Interception 60 2.5.5 Brute Force Attack 60 2.5.6 Page Defacement 61 2.5.7 Denial of Service 61 2.6 Cryptography 62 2.6.1 Symmetric Key and Asymmetric Key Cryptography 62 2.6.2 Hash Function 63 2.6.3 Digital Signature 64 2.6.4 Digital Certificate 64 2.6.5 Cryptography Programs 66 3 Information Theory 68 3.1 Information Measurement 70 3.2 Requirements for an Information Metric 71 3.3 Source Coding 77 3.4 Extension of a Memoryless Discrete Source 79 3.4.1 Improving the Coding Efficiency 79 3.5 Prefix Codes 80 3.6 The Information Unit 83 4 Source Coding 86 4.1 Types of Source Codes 86 4.1.1 Block Codes 86 4.1.2 Non-Singular Codes 86 4.1.3 Uniquely Decodable Codes 87 4.1.4 Instantaneous Codes 88 4.2 Construction of Instantaneous Codes 90 4.3 Kraft Inequality 92 4.4 Huffman Code 94 4.4.1 Constructing a Binary Huffman Code 95 5 Information Transmission and Channel Capacity 100 5.1 The Concept of Information Theory 101 5.2 Joint Information Measurement 101 5.3 Conditional Entropy 103 5.4 Model for a Communication Channel 104 5.5 Noiseless Channel 105 5.6 Channel with Independent Output and Input 105 5.7 Relations Between the Entropies 106 5.8 Mutual Information 107 5.9 Channel Capacity 109 5.9.1 Capacity of the Memoryless Discrete Channel 110 5.9.2 Relative Redundancy and Efficiency 110 6 Computer Networks 116 6.1 Data Flow in Networks 117 6.1.1 Capacity of a Channel Composition 117 6.1.2 Stationary Data Flow 121 6.2 Queue Models 124 6.2.1 Markov Model 126 6.2.2 Solution for a Stable Network 128 6.2.3 Constant Arrival Rate System 129 6.2.4 Efficient Server Model 132 6.2.5 Model with Discouraged Arrivals 133 6.2.6 Models of Queues M/G/1, M/M/1, and M/D/1 134 6.3 Local Area Networks 137 6.3.1 Definitions and Functions 137 6.3.2 Applications for Local Area Networks 138 6.3.3 Network Structure and Topology 138 6.3.4 Channel Access Techniques 141 6.3.5 Traffic on the Network 142 6.3.6 Performance Measures 143 7 Network Protocols and Architecture 148 7.1 What the World Was Like Without the Internet 148 7.2 Layer Architecture 152 7.2.1 The ISO Reference Model 154 7.2.2 Reference Model layers 154 7.2.3 IEEE 802 Standards for Computer Networks 158 8 The TCP/IP Protocol 160 8.1 TCP/IP Protocol History 160 8.2 Internet Coordination 160 8.3 Types of Networks 162 8.4 Transmission Protocols 162 8.5 Interconnection Equipment 163 8.6 Interconnection Protocols 163 8.6.1 Other TCP Services 164 8.6.2 TCP Header Structure 165 8.7 The IP Protocol 166 8.7.1 IP Addresses 166 8.7.2 Example of a DNS 167 8.7.3 Datagram Fragmentation 167 8.7.4 IP Routing 168 8.7.5 IP Address Resolution 169 8.7.6 User Datagram Protocol 171 8.7.7 Applications that Use TCP and UDP 171 8.7.8 Applications that Use TCP and UDP 172 8.8 The TCP/IP Protocol 172 8.8.1 Application Layer 173 8.8.2 Transport Layer 174 8.8.3 Internet Layer 176 8.9 Security Protocols for TCP/IP 178 8.9.1 IP Security Protocol 179 8.9.2 Vulnerabilities and Precautions Regarding TCP/IP 180 8.9.3 Vulnerabilities and Precautions Regarding TCP/IP Services 181 9 Network Security 184 9.1 Cryptography Applied to Computer Networks 184 9.1.1 Potential Network Vulnerabilities 185 9.1.2 Listening, Data Change, Forged Identity 185 9.1.3 Password-Based Attacks 186 9.1.4 Denial of Service 186 9.1.5 Password Break Attack 187 9.1.6 Sniffer Attack 187 9.1.7 Attack to the Application Layer 188 9.2 Alternatives to Prevent Attacks 188 9.2.1 Security Technologies 189 9.2.2 Security Mechanisms for the Application Layer 189 9.2.3 Security Mechanisms for the Transport Layer 190 9.2.4 Security Mechanisms for the Network Layer 190 9.3 Secure Sockets Layer Protocol 191 9.3.1 Encryption Used with SSL 193 9.4 Exchange of Information for the Safe Sockets Layer 194 9.4.1 Server Authentication 196 9.4.2 Attack of the Man in the Middle 198 9.4.3 Client Authentication 198 9.5 Data Protection with IPsec 200 9.5.1 Security Associations 201 9.5.2 Tunneling 203 9.5.3 Authentication Header 204 9.5.4 Authentication Header Format 204 9.5.5 Authentication Header in Transport and Tunnel Modes 207 9.5.6 AH in Tunnel Mode 207 9.6 Encapsulated Security Load 209 9.6.1 ESP Package Format 209 9.6.2 ESP in Transport Mode 211 9.6.3 ESP in Tunnel Mode 211 9.7 Espionage Between Countries 211 10 Theoretical Cryptography 214 10.1 Introduction 214 10.2 Cryptographic Aspects of Computer Networks 215 10.2.1 Potential Vulnerabilities of Computer Networks 215 10.3 Principles of Cryptography 216 10.4 Information Theoretical Aspects of Cryptography 217 10.4.1 Relations Between the Entropies 219 10.5 Mutual Information for Cryptosystems 220 11 The Hash Function 222 11.1 Introduction to Network Security 222 11.2 Hash Functions 223 11.3 Objectives of the Hash Function 224 11.4 Mathematical Preliminaries 226 11.5 Privacy Amplification 227 11.6 Conclusion 229 12 Criminal Cases 230 12.1 Introduction to Cybercrimes 230 12.2 Types of Cybercrimes 230 12.3 Famous Cybercrimes 231 12.3.1 The Mythical Pegasus 232 12.3.2 Hackers' Attack to Colonial and JBS 232 12.3.3 The Biggest Ransomware Attack Ever 233 12.3.4 Credit Cards Data Stolen from Home Depot's System 233 12.3.5 Largest Theft of Customer Data 233 12.3.6 Yahoo Data Breach 234 12.3.7 Customer's Data Stolen from Healthcare Companies 234 12.3.8 Social Security Numbers Stolen from IRS 234 12.3.9 Government Data Breach Due to Outdated Technology 235 12.3.10 Google Corporate Servers Hacked in China 235 12.3.11 Sony Pictures Hacked 235 12.3.12 Wikileaks Obtained Sensitive Information from the Democratic National Committee 236 12.3.13 A DDoS Attack that Took Down Twitter, PayPal, and Netflix 236 12.3.14 MafiaBoy's Teenage Crimes 236 12.3.15 Epsilon Attacked by Hackers 237 12.3.16 NHS Patients Had Their Computers Infected 237 12.3.17 When the United States Department of Defense was Attacked 238 12.3.18 The Ashley Madison Hack 238 12.3.19 The Stuxnet Worm Attack 238 12.3.20 The Iceman Attack 239 12.3.21 Bitcoin Stolen from Bitfinex Exchange in Hong Kong 239 12.3.22 Crypto Exchange Bithumb Hacked 239 12.3.23 Espionage Between Partners 240 Appendix A Probability Theory 242 A.1 Set Theory and Measure 242 A.1.1 Basic Set Theory 243 A.1.2 Some Operations on Sets 244 A.1.3 Families of Sets 245 A.1.4 Indexing of Sets 246 A.1.5 An Algebra of Sets 247 A.1.6 The Borel Algebra 248 A.2 Basic Probability Theory 248 A.2.1 The Axioms of Probability 249 A.2.2 Bayes' Rule 250 A.3 Random Variables 251 A.3.1 Expected Value of a Random Variable 252 A.3.2 Moments of a Random Variable 252 A.3.3 Variance of a Random Variable 253 A.3.4 Characteristic Function 253 A.3.4.1 Two Important Distributions 253 A.3.5 Joint Random Variables 254 Appendix B Cryptoalgorithms and Cryptosystems 258 Appendix C Glossary of Information Security Terms 272 References 294 Index 302 About the Author 320 Back Cover 324 "Starting with the historical evolution of computer and communications networks and their security, the book then arrives at the main definitions of cryptography and network security. Next, the basics of information theory, how to measure information, the information associated with a certain source are also discussed. Source codes are presented, along with the concepts of information transmission, joint information, conditional entropy, mutual information and channel capacity. Computer networks are discussed, including the main protocols and network architectures, and the important TCP/IP protocol. Network security, a topic intrinsically connected to computer networks and the Internet, is presented, along with information about basic hacker attacks, alternatives to prevent attacks, data protection and secure protocols. The information theoretical aspects of cryptography are described including the hash function. An appendix includes a review of probability theory. Illustrations and graphics will help the reader understand the theory"-- Provided by publisher