Internet Cryptography: Table of Contents

[Cover]
Contents of Internet Cryptography

by Richard E. Smith
ISBN 0-201-92480-3, Addison Wesley, 1997

Preface

xv

Who this Book is For xv

How this Book is Organized xvi

Crypto Today and Tomorrow xviii

Comments and Questions xviii

Acknowledgments

xix

Chapter 1 Introduction

1

1.1 The Basic Problem 1

1.2 Essentials of Crypto 4

1.2.1 Crypto is Hard to Use 6

1.2.2 Balancing Crypto Use with Your Objectives 7

1.3 Essentials of Networking and the Internet 8

1.3.1 Protocol Layers and Network Products 9

1.3.2 Internet Technology 12

1.3.3 Internet Protocols in Your Host 14

1.3.4 The Internet Security Problem 16

1.3.5 An Internet Rogue's Gallery 19

1.4 Setting Realistic Security Objectives 20

1.5 Appropriate Communications Security 22

1.5.1 Communications Security Goals 23

1.5.2 Internet Crypto Techniques 25

1.6 Legal Restrictions 27

1.7 For Further Information 30

Chapter 2 Encryption Basics

33

2.1 Encryption Building Blocks 33

2.1.1 Stream Ciphers 34

2.1.2 Block Ciphers 36

2.2 How Crypto Systems Fail 42

2.2.1 Cryptanalysis and Modern Codes 44

2.2.2 Brute Force Cracking of Secret Keys 46

2.2.3 Attacks on Improper Crypto Use 50

2.3 Choosing Between Strong and Weak Crypto 51

2.3.1 Properties of Good Crypto Algorithms 52

2.3.2 Crypto Algorithms to Consider 55

2.3.3 Selecting a Block Cipher Mode 57

2.3.4 Identifying a Safe Key Length 58

2.3.5 Levels of Risk for Different Applications 60

2.4 For Further Information 62

Chapter 3 Link Encryption

63

3.1 Security Objectives 63

3.2 Product Example: In-line Encryptor 65

3.2.1 Red/Black Separation 66

3.2.2 Crypto Algorithm and Keying 67

3.2.3 Encryptor Vulnerabilities 68

3.2.4 Product Security Requirements 71

3.3 Deployment Example: Point-to-Point Encryption 72

3.3.1 Point-to-Point Practical Limitations 73

3.3.2 Physical Protection and Control 74

3.3.3 Deployment Security Requirements 75

3.4 Deployment Example: IP-routed Configuration 76

3.4.1 Site Protection 77

3.4.2 Networkwide Security 78

3.4.3 Deployment Security Requirements 81

3.5 Key Recovery and Escrowed Encryption 82

3.6 For Further Information 85

Chapter 4 Managing Secret Keys

87

4.1 Security Objectives 87

4.2 Basic Issues in Secret Key Management 88

4.3 Technology: Random Key Generation 89

4.3.1 Random Seeding 90

4.3.2 Pseudorandom Number Generators 92

4.3.3 Technical Security Requirements 95

4.4 Deployment Example: Manual Key Distribution 95

4.4.1 Preparing Secret Keys for Delivery 96

4.4.2 Batch Generation of Keys 98

4.4.3 Printing Keys on Paper 102

4.4.4 Key Packaging and Delivery 103

4.4.5 Key Splitting for Safer Delivery 104

4.4.6 Deployment Security Requirements 106

4.5 Technology: Automatic Rekeying 107

4.5.1 ANSI X9.17 Point-to-Point Rekeying 108

4.5.2 Variations of X9.17 110

4.5.3 Technical Security Requirements 112

4.6 Key Distribution Centers (KDCs) 113

4.7 Maintaining Keys and System Security 116

4.8 For Further Information 117

Chapter 5 Security at the IP Layer

119

5.1 Security Objectives 119

5.2 Basic Issues with Using IPSEC 120

5.3 Technology: Cryptographic Checksums 121

5.3.1 One-way Hash Functions 123

5.3.2 Technical Security Requirements 126

5.4 IPSEC: IP Security Protocol 127

5.4.1 IPSEC Authentication 130

5.4.2 IPSEC Encryption 131

5.5 IPSEC Key Management 134

5.6 Other TCP/IP Network Security Protocols 137

5.7 For Further Information 139

Chapter 6 Virtual Private Networks

141

6.1 Security Objectives 142

6.2 Basic Issues with VPNs 142

6.3 Technology: IPSEC Proxy Cryptography 143

6.3.1 ESP Tunnel Mode 145

6.3.2 ESP Transport Mode 147

6.4 Product Example: IPSEC Encrypting Router 148

6.4.1 Blocking Classic Internet Attacks 149

6.4.2 Product Security Requirements 151

6.5 Deployment Example: Site-to-Site Encryption 153

6.5.1 Header Usage and Security 156

6.5.2 Deployment Security Requirements 159

6.6 For Further Information 159

Chapter 7 Remote Access with IPSEC

161

7.1 Security Objectives 161

7.2 Basic Issues with IPSEC Clients 162

7.3 Product Example: IPSEC Client 163

7.3.1 Client Security Associations 165

7.3.2 Client Self-Defense on the Internet 166

7.3.3 Client Theft and Key Protection 167

7.3.4 Product Security Requirements 169

7.4 Deployment Example: Client-to-Server Site Access 171

7.4.1 Remote Access Security Issues 172

7.4.2 Deployment Security Requirements 175

7.5 For Further Information 176

Chapter 8 IPSEC and Firewalls

177

8.1 Security Objectives 177

8.2 Basic Issues with IPSEC and Firewalls 178

8.3 Internet Firewalls 179

8.3.1 What Firewalls Control 180

8.3.2 How Firewalls Control Access 181

8.3.3 Firewall Control Mechanisms 183

8.4 Product Example: IPSEC Firewall 187

8.4.1 Administering Multiple Sites 189

8.4.2 Product Security Requirements 190

8.5 Deployment Example: A VPN with a Firewall 191

8.5.1 Establishing a Site Security Policy 192

8.5.2 Chosen Plaintext Attack on a Firewall 193

8.5.3 Deployment Security Requirements 195

8.6 For Further Information 195

Chapter 9 Public Key Crypto and SSL

197

9.1 Public Key Cryptography 197

9.1.1 Evolution of Public Key Crypto 199

9.1.2 Diffie-Hellman Public Key Technique 200

9.2.1 Brute Force Attacks on RSA 205

9.2.2 Other RSA Vulnerabilities 208

9.2.3 Technical Security Requirements 211

9.3 Technology: Secret Key Exchange with RSA Crypto 212

9.3.1 Attacking Public Key Distribution 213

9.3.2 Public Key versus Secret Key Exchange 215

9.3.3 Technical Security Requirements 218

9.4 Secure Sockets Layer 218

9.4.1 Other SSL Properties 222

9.4.2 Basic Attacks Against SSL 223

9.4.3 SSL Security Evolution 226

9.5 For Further Information 228

Chapter 10 World Wide Web Transaction Security

229

10.1 Security Objectives 229

10.2 Basic Issues in Internet Transaction Security 230

10.3 Transactions on the World Wide Web 232

10.3.1 Transactions with Web Forms 233

10.3.2 Web Form Security Services 235

10.4 Security Alternatives for Web Forms 236

10.4.1 Password Protection 237

10.4.2 Network-level Security (IPSEC) 237

10.4.3 Transport-level Security (SSL) 238

10.4.4 Application-level Security (SHTTP) 239

10.4.5 Client Authentication Alternatives 240

10.5 Product Example: Web Browser with SSL 242

10.5.1 Browser Cryptographic Services 244

10.5.2 Authentication Capabilities 245

10.5.3 Client Security and Executable Contents 247

10.5.4 Product Security Requirements 250

10.6 Product Example: Web Server with SSL 252

10.6.1 Web Server Vulnerabilities 253

10.6.2 Mandatory Protection 257

10.6.3 Product Security Requirements 258

10.7 Deployment Example: Vending with Exportable Encryption 259

10.7.1 Export Restrictions and Transaction Security 261

10.7.2 Site Configuration 262

10.7.3 Deployment Security Requirements 264

10.8 For Further Information 266

Chapter 11 Secured Electronic Mail

267

11.1 Security Objectives 267

11.2 Basic Issues with E-Mail Security 268

11.3 Basics of Internet Electronic Mail 269

11.3.1 Internet E-Mail Software Architecture 271

11.3.2 E-Mail Security Problems 272

11.4 Technology: Off-line Message Keying 275

11.4.1 Encryption Tokens 276

11.4.2 Technical Security Requirements 277

11.5 Technology: Digital Signatures 278

11.5.1 Attacks on Digital Signatures 280

11.5.2 The Digital Signature Standard 284

11.5.3 Technical Security Requirements 286

11.6 Product Example: Secure E-Mail Client 287

11.6.1 Basic Secure Client Features 288

11.6.2 E-Mail Client Security Issues 290

11.6.3 Product Security Requirements 292

11.7 E-Mail Deployment 293

11.8 For Further Information 294

Chapter 12 Public Key Certificates

295

12.1 Security Objectives 295

12.2 Distributing Public Keys 296

12.3 Technology: Public Key Certificates 299

12.3.1 Generating Public Key Pairs 301

12.3.2 Certificate Revocation 302

12.3.3 Certification Authority Workstation 303

12.3.4 Technical Security Requirements 305

12.4 Certificate Distribution 306

12.4.1 Transparent Distribution 307

12.4.2 Interactive Distribution 308

12.5 Centralized Certification Authority 310

12.5.1 Netscape Server Authentication 311

12.5.2 Handling Multiple Certification Authorities 312

12.6 Hierarchical Certification Authority 313

12.6.1 PEM Internet Certification Hierarchy 314

12.6.2 Private Trees 316

12.7 PGP "Web of Trust" 316

12.8 For Further Information 319

Appendix A: Glossary

321

Appendix B: Bibliography

341

Index

345

Preface	xv
	Who this Book is For	xv
	How this Book is Organized	xvi
	Crypto Today and Tomorrow	xviii
	Comments and Questions	xviii
Acknowledgments	xix
Chapter 1 Introduction	1
	1.1 The Basic Problem	1
	1.2 Essentials of Crypto	4
		1.2.1 Crypto is Hard to Use	6
		1.2.2 Balancing Crypto Use with Your Objectives	7
	1.3 Essentials of Networking and the Internet	8
		1.3.1 Protocol Layers and Network Products	9
		1.3.2 Internet Technology	12
		1.3.3 Internet Protocols in Your Host	14
		1.3.4 The Internet Security Problem	16
		1.3.5 An Internet Rogue's Gallery	19
	1.4 Setting Realistic Security Objectives	20
	1.5 Appropriate Communications Security	22
		1.5.1 Communications Security Goals	23
		1.5.2 Internet Crypto Techniques	25
	1.6 Legal Restrictions	27
	1.7 For Further Information	30
Chapter 2 Encryption Basics	33
	2.1 Encryption Building Blocks	33
		2.1.1 Stream Ciphers	34
		2.1.2 Block Ciphers	36
	2.2 How Crypto Systems Fail	42
		2.2.1 Cryptanalysis and Modern Codes	44
		2.2.2 Brute Force Cracking of Secret Keys	46
		2.2.3 Attacks on Improper Crypto Use	50
	2.3 Choosing Between Strong and Weak Crypto	51
		2.3.1 Properties of Good Crypto Algorithms	52
		2.3.2 Crypto Algorithms to Consider	55
		2.3.3 Selecting a Block Cipher Mode	57
		2.3.4 Identifying a Safe Key Length	58
		2.3.5 Levels of Risk for Different Applications	60
	2.4 For Further Information	62
Chapter 3 Link Encryption	63
	3.1 Security Objectives	63
	3.2 Product Example: In-line Encryptor	65
		3.2.1 Red/Black Separation	66
		3.2.2 Crypto Algorithm and Keying	67
		3.2.3 Encryptor Vulnerabilities	68
		3.2.4 Product Security Requirements	71
	3.3 Deployment Example: Point-to-Point Encryption	72
		3.3.1 Point-to-Point Practical Limitations	73
		3.3.2 Physical Protection and Control	74
		3.3.3 Deployment Security Requirements	75
	3.4 Deployment Example: IP-routed Configuration	76
		3.4.1 Site Protection	77
		3.4.2 Networkwide Security	78
		3.4.3 Deployment Security Requirements	81
	3.5 Key Recovery and Escrowed Encryption	82
	3.6 For Further Information	85
Chapter 4 Managing Secret Keys	87
	4.1 Security Objectives	87
	4.2 Basic Issues in Secret Key Management	88
	4.3 Technology: Random Key Generation	89
		4.3.1 Random Seeding	90
		4.3.2 Pseudorandom Number Generators	92
		4.3.3 Technical Security Requirements	95
	4.4 Deployment Example: Manual Key Distribution	95
		4.4.1 Preparing Secret Keys for Delivery	96
		4.4.2 Batch Generation of Keys	98
		4.4.3 Printing Keys on Paper	102
		4.4.4 Key Packaging and Delivery	103
		4.4.5 Key Splitting for Safer Delivery	104
		4.4.6 Deployment Security Requirements	106
	4.5 Technology: Automatic Rekeying	107
		4.5.1 ANSI X9.17 Point-to-Point Rekeying	108
		4.5.2 Variations of X9.17	110
		4.5.3 Technical Security Requirements	112
	4.6 Key Distribution Centers (KDCs)	113
	4.7 Maintaining Keys and System Security	116
	4.8 For Further Information	117
Chapter 5 Security at the IP Layer	119
	5.1 Security Objectives	119
	5.2 Basic Issues with Using IPSEC	120
	5.3 Technology: Cryptographic Checksums	121
		5.3.1 One-way Hash Functions	123
		5.3.2 Technical Security Requirements	126
	5.4 IPSEC: IP Security Protocol	127
		5.4.1 IPSEC Authentication	130
		5.4.2 IPSEC Encryption	131
	5.5 IPSEC Key Management	134
	5.6 Other TCP/IP Network Security Protocols	137
	5.7 For Further Information	139
Chapter 6 Virtual Private Networks	141
	6.1 Security Objectives	142
	6.2 Basic Issues with VPNs	142
	6.3 Technology: IPSEC Proxy Cryptography	143
		6.3.1 ESP Tunnel Mode	145
		6.3.2 ESP Transport Mode	147
	6.4 Product Example: IPSEC Encrypting Router	148
		6.4.1 Blocking Classic Internet Attacks	149
		6.4.2 Product Security Requirements	151
	6.5 Deployment Example: Site-to-Site Encryption	153
		6.5.1 Header Usage and Security	156
		6.5.2 Deployment Security Requirements	159
	6.6 For Further Information	159
Chapter 7 Remote Access with IPSEC	161
	7.1 Security Objectives	161
	7.2 Basic Issues with IPSEC Clients	162
	7.3 Product Example: IPSEC Client	163
		7.3.1 Client Security Associations	165
		7.3.2 Client Self-Defense on the Internet	166
		7.3.3 Client Theft and Key Protection	167
		7.3.4 Product Security Requirements	169
	7.4 Deployment Example: Client-to-Server Site Access	171
		7.4.1 Remote Access Security Issues	172
		7.4.2 Deployment Security Requirements	175
	7.5 For Further Information	176
Chapter 8 IPSEC and Firewalls	177
	8.1 Security Objectives	177
	8.2 Basic Issues with IPSEC and Firewalls	178
	8.3 Internet Firewalls	179
		8.3.1 What Firewalls Control	180
		8.3.2 How Firewalls Control Access	181
		8.3.3 Firewall Control Mechanisms	183
	8.4 Product Example: IPSEC Firewall	187
		8.4.1 Administering Multiple Sites	189
		8.4.2 Product Security Requirements	190
	8.5 Deployment Example: A VPN with a Firewall	191
		8.5.1 Establishing a Site Security Policy	192
		8.5.2 Chosen Plaintext Attack on a Firewall	193
		8.5.3 Deployment Security Requirements	195
	8.6 For Further Information	195
Chapter 9 Public Key Crypto and SSL	197
	9.1 Public Key Cryptography	197
		9.1.1 Evolution of Public Key Crypto	199
		9.1.2 Diffie-Hellman Public Key Technique	200
		9.2.1 Brute Force Attacks on RSA	205
		9.2.2 Other RSA Vulnerabilities	208
		9.2.3 Technical Security Requirements	211
	9.3 Technology: Secret Key Exchange with RSA Crypto	212
		9.3.1 Attacking Public Key Distribution	213
		9.3.2 Public Key versus Secret Key Exchange	215
		9.3.3 Technical Security Requirements	218
	9.4 Secure Sockets Layer	218
		9.4.1 Other SSL Properties	222
		9.4.2 Basic Attacks Against SSL	223
		9.4.3 SSL Security Evolution	226
	9.5 For Further Information	228
Chapter 10 World Wide Web Transaction Security	229
	10.1 Security Objectives	229
	10.2 Basic Issues in Internet Transaction Security	230
	10.3 Transactions on the World Wide Web	232
		10.3.1 Transactions with Web Forms	233
		10.3.2 Web Form Security Services	235
	10.4 Security Alternatives for Web Forms	236
		10.4.1 Password Protection	237
		10.4.2 Network-level Security (IPSEC)	237
		10.4.3 Transport-level Security (SSL)	238
		10.4.4 Application-level Security (SHTTP)	239
		10.4.5 Client Authentication Alternatives	240
	10.5 Product Example: Web Browser with SSL	242
		10.5.1 Browser Cryptographic Services	244
		10.5.2 Authentication Capabilities	245
		10.5.3 Client Security and Executable Contents	247
		10.5.4 Product Security Requirements	250
	10.6 Product Example: Web Server with SSL	252
		10.6.1 Web Server Vulnerabilities	253
		10.6.2 Mandatory Protection	257
		10.6.3 Product Security Requirements	258
	10.7 Deployment Example: Vending with Exportable Encryption	259
		10.7.1 Export Restrictions and Transaction Security	261
		10.7.2 Site Configuration	262
		10.7.3 Deployment Security Requirements	264
	10.8 For Further Information	266
Chapter 11 Secured Electronic Mail	267
	11.1 Security Objectives	267
	11.2 Basic Issues with E-Mail Security	268
	11.3 Basics of Internet Electronic Mail	269
		11.3.1 Internet E-Mail Software Architecture	271
		11.3.2 E-Mail Security Problems	272
	11.4 Technology: Off-line Message Keying	275
		11.4.1 Encryption Tokens	276
		11.4.2 Technical Security Requirements	277
	11.5 Technology: Digital Signatures	278
		11.5.1 Attacks on Digital Signatures	280
		11.5.2 The Digital Signature Standard	284
		11.5.3 Technical Security Requirements	286
	11.6 Product Example: Secure E-Mail Client	287
		11.6.1 Basic Secure Client Features	288
		11.6.2 E-Mail Client Security Issues	290
		11.6.3 Product Security Requirements	292
	11.7 E-Mail Deployment	293
	11.8 For Further Information	294
Chapter 12 Public Key Certificates	295
	12.1 Security Objectives	295
	12.2 Distributing Public Keys	296
	12.3 Technology: Public Key Certificates	299
		12.3.1 Generating Public Key Pairs	301
		12.3.2 Certificate Revocation	302
		12.3.3 Certification Authority Workstation	303
		12.3.4 Technical Security Requirements	305
	12.4 Certificate Distribution	306
		12.4.1 Transparent Distribution	307
		12.4.2 Interactive Distribution	308
	12.5 Centralized Certification Authority	310
		12.5.1 Netscape Server Authentication	311
		12.5.2 Handling Multiple Certification Authorities	312
	12.6 Hierarchical Certification Authority	313
		12.6.1 PEM Internet Certification Hierarchy	314
		12.6.2 Private Trees	316
	12.7 PGP "Web of Trust"	316
	12.8 For Further Information	319
Appendix A: Glossary	321
Appendix B: Bibliography	341
Index	345

Richard E. Smith, smith@smat.us
Web design assistance by Anne Chenette
Last update: 7/25/2002

Contents of Internet Cryptography