Information Security

"Preface xv About The Author xix Acknowledgments xxi 1 Introductions 1 1.1 The Cast of Characters 1 1.2 Alice's Online Bank 2 1.2.1 Confidentiality, Integrity, and Availability 2 1.2.2 Beyond CIA 2 1.3 About This Book 4 1.3.1 Cryptography 4 1.3.2 Access Control 5 1.3.3 Network Security 6 1.3.4 Software 6 1.4 The People Problem 7 1.5 Principles and Practice 7 1.6 Problems 8 I Crypto 13 2 Classic Cryptography 15 2.1 Introduction 15 2.2 How to Speak Crypto 15 2.3 Classic Crypto 17 2.3.1 Simple Substitution Cipher 18 2.3.2 Cryptanalysis of a Simple Substitution 20 2.3.3 Definition of Secure 21 2.3.4 Double Transposition Cipher 22 2.3.5 One-Time Pad 23 2.3.6 Codebook Cipher 27 viii CONTENTS 2.4 Classic Crypto in History 28 2.4.1 Ciphers of the Election of 1876 28 2.4.2 Zimmermann Telegram 30 2.4.3 Project VENONA 32 2.5 Modern Crypto History 33 2.6 A Taxonomy of Cryptography 36 2.7 A Taxonomy of Cryptanalysis 37 2.8 Summary 39 2.9 Problems 39 3 Symmetric Ciphers 45 3.1 Introduction 45 3.2 Stream Ciphers 46 3.2.1 A5/1 47 3.2.2 RC4 49 3.3 Block Ciphers 51 3.3.1 Feistel Cipher 51 3.3.2 DES 52 3.3.3 Triple DES 57 3.3.4 AES 59 3.3.5 TEA 62 3.3.6 Block Cipher Modes 64 3.4 Integrity 68 3.5 Quantum Computers and Symmetric Crypto 70 3.6 Summary 72 3.7 Problems 72 4 Public Key Crypto 79 4.1 Introduction 79 4.2 Knapsack 82 4.3 RSA 85 4.3.1 Textbook RSA Example 87 4.3.2 Repeated Squaring 88 4.3.3 Speeding Up RSA 90 4.4 Diffie-Hellman 91 4.5 Elliptic Curve Cryptography 93 4.5.1 Elliptic Curve Math 93 4.5.2 ECC Diffie-Hellman 95 4.5.3 Realistic Elliptic Curve Example 96 4.6 Public Key Notation 97 4.7 Uses for Public Key Crypto 98 4.7.1 Confidentiality in the Real World 98 4.7.2 Signatures and Non-repudiation 99 CONTENTS ix 4.7.3 Confidentiality and Non-repudiation 99 4.8 Certificates and PKI 102 4.9 Quantum Computers and Public Key 104 4.10 Summary 106 4.11 Problems 106 5 Crypto Hash Functions++ 115 5.1 Introduction 115 5.2 What is a Cryptographic Hash Function? 116 5.3 The Birthday Problem 117 5.4 A Birthday Attack 119 5.5 Non-Cryptographic Hashes 120 5.6 SHA-3 121 5.7 HMAC 124 5.8 Cryptographic Hash Applications 126 5.8.1 Online Bids 126 5.8.2 Blockchain 127 5.9 Miscellaneous Crypto-Related Topics 136 5.9.1 Secret Sharing 136 5.9.2 Random Numbers 140 5.9.3 Information Hiding 143 5.10 Summary 147 5.11 Problems 147 II Access Control 159 6 Authentication 161 6.1 Introduction 161 6.2 Authentication Methods 162 6.3 Passwords 163 6.3.1 Keys Versus Passwords 164 6.3.2 Choosing Passwords 164 6.3.3 Attacking Systems via Passwords 166 6.3.4 Password Verification 167 6.3.5 Math of Password Cracking 168 6.3.6 Other Password Issues 173 6.4 Biometrics 174 6.4.1 Types of Errors 176 6.4.2 Biometric Examples 176 6.4.3 Biometric Error Rates 181 6.4.4 Biometric Conclusions 182 6.5 Something You Have 182 x CONTENTS 6.6 Two-Factor Authentication 183 6.7 Single Sign-On and Web Cookies 183 6.8 Summary 184 6.9 Problems 185 7 Authorization 195 7.1 Introduction 195 7.2 A Brief History of Authorization 196 7.2.1 The Orange Book 196 7.2.2 The Common Criteria 199 7.3 Access Control Matrix 200 7.3.1 ACLs and Capabilities 201 7.3.2 Confused Deputy 202 7.4 Multilevel Security Models 204 7.4.1 Bell-LaPadula 206 7.4.2 Biba's Model 207 7.4.3 Compartments 208 7.5 Covert Channels 210 7.6 Inference Control 212 7.7 CAPTCHA 214 7.8 Summary 216 7.9 Problems 216 III Topics in Network Security 221 8 Network Security Basics 223 8.1 Introduction 223 8.2 Networking Basics 223 8.2.1 The Protocol Stack 225 8.2.2 Application Layer 226 8.2.3 Transport Layer 228 8.2.4 Network Layer 231 8.2.5 Link Layer 233 8.3 Cross-Site Scripting Attacks 235 8.4 Firewalls 236 8.4.1 Packet Filter 238 8.4.2 Stateful Packet Filter 240 8.4.3 Application Proxy 240 8.4.4 Defense in Depth 242 8.5 Intrusion Detection Systems 243 8.5.1 Signature-Based IDS 245 8.5.2 Anomaly-Based IDS 246 CONTENTS xi 8.6 Summary 250 8.7 Problems 250 9 Simple Authentication Protocols 257 9.1 Introduction 257 9.2 Simple Security Protocols 259 9.3 Authentication Protocols 261 9.3.1 Authentication Using Symmetric Keys 264 9.3.2 Authentication Using Public Keys 267 9.3.3 Session Keys 268 9.3.4 Perfect Forward Secrecy 270 9.3.5 Mutual Authentication, Session Key, and PFS 273 9.3.6 Timestamps 273 9.4 ``Authentication"""" and TCP 275 9.5 Zero Knowledge Proofs 278 9.6 Tips for Analyzing Protocols 282 9.7 Summary 284 9.8 Problems 284 10 Real-World Security Protocols 293 10.1 Introduction 293 10.2 SSH 294 10.2.1 SSH and the Man-in-the-Middle 295 10.3 SSL 296 10.3.1 SSL and the Man-in-the-Middle 299 10.3.2 SSL Connections 300 10.3.3 SSL Versus IPsec 300 10.4 IPsec 301 10.4.1 IKE Phase 1 302 10.4.2 IKE Phase 2 309 10.4.3 IPsec and IP Datagrams 310 10.4.4 Transport and Tunnel Modes 311 10.4.5 ESP and AH 313 10.5 Kerberos 314 10.5.1 Kerberized Login 316 10.5.2 Kerberos Ticket 316 10.5.3 Security of Kerberos 318 10.6 WEP 319 10.6.1 WEP Authentication 319 10.6.2 WEP Encryption 320 10.6.3 WEP Non-Integrity 320 10.6.4 Other WEP Issues 321 10.6.5 WEP: The Bottom Line 322 xii CONTENTS 10.7 GSM 322 10.7.1 GSM Architecture 323 10.7.2 GSM Security Architecture 324 10.7.3 GSM Authentication Protocol 326 10.7.4 GSM Security Flaws 327 10.7.5 GSM Conclusions 329 10.7.6 3GPP 330 10.8 Summary 330 10.9 Problems 331 IV Software 339 11 Software Flaws and Malware 341 11.1 Introduction 341 11.2 Software Flaws 341 11.2.1 Buffer Overflow 345 11.2.2 Incomplete Mediation 356 11.2.3 Race Conditions 356 11.3 Malware 358 11.3.1 Malware Examples 359 11.3.2 Malware Detection 365 11.3.3 The Future of Malware 367 11.3.4 The Future of Malware Detection 369 11.4 Miscellaneous Software-Based Attacks 369 11.4.1 Salami Attacks 369 11.4.2 Linearization Attacks 370 11.4.3 Time Bombs 371 11.4.4 Trusting Software 372 11.5 Summary 373 11.6 Problems 373 12 Insecurity in Software 381 12.1 Introduction 381 12.2 Software Reverse Engineering 382 12.2.1 Reversing Java Bytecode 384 12.2.2 SRE Example 385 12.2.3 Anti-Disassembly Techniques 390 12.2.4 Anti-Debugging Techniques 391 12.2.5 Software Tamper Resistance 392 12.3 Software Development 393 12.3.1 Flaws and Testing 395 12.3.2 Secure Software Development? 396 CONTENTS xiii 12.4 Summary 396 12.5 Problems 397 Appendix 403 A-1 Modular Arithmetic 403 A-2 Permutations 405 A-3 Probability 406 A-4 DES Permutations 406 Index 418"