book

Computer Security: Art and Science

Name: Computer Security: Art and Science
Author: Matt Bishop
ISBN: 0201440997

by Matt Bishop

December 2002

Intermediate to advanced

1136 pages

32h 54m

English

Addison-Wesley Professional

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Copyright
Dedication
Preface
GoalsPhilosophyOrganizationRoadmapDependenciesBackgroundUndergraduate LevelGraduate LevelPractitionersSpecial AcknowledgmentAcknowledgments
1. Introduction
1. An Overview of Computer Security
1.1. The Basic Components1.1.1. Confidentiality1.1.2. Integrity1.1.3. Availability1.2. Threats1.3. Policy and Mechanism1.3.1. Goals of Security1.4. Assumptions and Trust1.5. Assurance1.5.1. Specification1.5.2. Design1.5.3. Implementation1.6. Operational Issues1.6.1. Cost-Benefit Analysis1.6.2. Risk Analysis1.6.3. Laws and Customs1.7. Human Issues1.7.1. Organizational Problems1.7.2. People Problems1.8. Tying It All Together1.9. Summary1.10. Research Issues1.11. Further Reading1.12. Exercises
2. Foundations
2. Access Control Matrix
2.1. Protection State2.2. Access Control Matrix Model2.2.1. Access Control by Boolean Expression Evaluation2.2.2. Access Controlled by History2.3. Protection State Transitions2.3.1. Conditional Commands2.4. Copying, Owning, and the Attenuation of Privilege2.4.1. Copy Right2.4.2. Own Right2.4.3. Principle of Attenuation of Privilege2.5. Summary2.6. Research Issues2.7. Further Reading2.8. Exercises
3. Foundational Results
3.1. The General Question3.2. Basic Results3.3. The Take-Grant Protection Model3.3.1. Sharing of Rights3.3.2. Interpretation of the Model3.3.3. Theft in the Take-Grant Protection Model3.3.4. Conspiracy3.3.5. Summary3.4. Closing the Gap3.4.1. Schematic Protection Model3.4.1.1. Link Predicate3.4.1.2. Filter Function3.4.1.3. Putting It All Together3.4.1.4. Demand and Create Operations3.4.1.5. Safety Analysis3.5. Expressive Power and the Models3.5.1. Brief Comparison of HRU and SPM3.5.2. Extending SPM3.5.3. Simulation and Expressiveness3.5.4. Typed Access Matrix Model3.6. Summary3.7. Research Issues3.8. Further Reading3.9. Exercises
3. Policy
4. Security Policies
4.1. Security Policies4.2. Types of Security Policies4.3. The Role of Trust4.4. Types of Access Control4.5. Policy Languages4.5.1. High-Level Policy Languages4.5.2. Low-Level Policy Languages4.6. Example: Academic Computer Security Policy4.6.1. General University Policy4.6.2. Electronic Mail Policy4.6.2.1. The Electronic Mail Policy Summary4.6.2.2. The Full Policy4.6.2.3. Implementation at UC Davis4.7. Security and Precision4.8. Summary4.9. Research Issues4.10. Further Reading4.11. Exercises
5. Confidentiality Policies
5.1. Goals of Confidentiality Policies5.2. The Bell-LaPadula Model5.2.1. Informal Description5.2.2. Example: The Data General B2 UNIX System5.2.2.1. Assigning MAC Labels5.2.2.2. Using MAC Labels5.2.3. Formal Model5.2.3.1. Basic Security Theorem5.2.3.2. Rules of Transformation5.2.4. Example Model Instantiation: Multics5.2.4.1. The get-read Rule5.2.4.2. The give-read Rule5.3. Tranquility5.4. The Controversy over the Bell-LaPadula Model5.4.1. McLean's †-Property and the Basic Security Theorem5.4.2. McLean's System Z and More Questions5.4.3. Summary5.5. Summary5.6. Research Issues5.7. Further Reading5.8. Exercises

6. Integrity Policies
6.1. Goals6.2. Biba Integrity Model6.2.1. Low-Water-Mark Policy6.2.2. Ring Policy6.2.3. Biba's Model (Strict Integrity Policy)6.3. Lipner's Integrity Matrix Model6.3.1. Lipner's Use of the Bell-LaPadula Model6.3.2. Lipner's Full Model6.3.3. Comparison with Biba6.4. Clark-Wilson Integrity Model6.4.1. The Model6.4.1.1. A UNIX Approximation to Clark-Wilson6.4.2. Comparison with the Requirements6.4.3. Comparison with Other Models6.5. Summary6.6. Research Issues6.7. Further Reading6.8. Exercises
7. Hybrid Policies
7.1. Chinese Wall Model7.1.1. Informal Description7.1.2. Formal Model7.1.3. Bell-LaPadula and Chinese Wall Models7.1.4. Clark-Wilson and Chinese Wall Models7.2. Clinical Information Systems Security Policy7.2.1. Bell-LaPadula and Clark-Wilson Models7.3. Originator Controlled Access Control7.4. Role-Based Access Control7.5. Summary7.6. Research Issues7.7. Further Reading7.8. Exercises
8. Noninterference and Policy Composition
8.1. The Problem8.1.1. Composition of Bell-LaPadula Models8.2. Deterministic Noninterference8.2.1. Unwinding Theorem8.2.2. Access Control Matrix Interpretation8.2.3. Security Policies That Change over Time8.2.4. Composition of Deterministic Noninterference-Secure Systems8.3. Nondeducibility8.3.1. Compositon of Deducibly Secure Systems8.4. Generalized Noninterference8.4.1. Composition of Generalized Noninterference Systems8.5. Restrictiveness8.5.1. State Machine Model8.5.2. Composition of Restrictive Systems8.6. Summary8.7. Research Issues8.8. Further Reading8.9. Exercises
4. Implementation I: Cryptography
9. Basic Cryptography
9.1. What Is Cryptography?9.2. Classical Cryptosystems9.2.1. Transposition Ciphers9.2.2. Substitution Ciphers9.2.2.1. Vigenère Cipher9.2.2.2. One-Time Pad9.2.3. Data Encryption Standard9.2.4. Other Classical Ciphers9.3. Public Key Cryptography9.3.1. Diffie-Hellman9.3.2. RSA9.4. Cryptographic Checksums9.4.1. HMAC9.5. Summary9.6. Research Issues9.7. Further Reading9.8. Exercises
10. Key Management
10.1. Session and Interchange Keys10.2. Key Exchange10.2.1. Classical Cryptographic Key Exchange and Authentication10.2.2. Kerberos10.2.3. Public Key Cryptographic Key Exchange and Authentication10.3. Key Generation10.4. Cryptographic Key Infrastructures10.4.1. Merkle's Tree Authentication Scheme10.4.2. Certificate Signature Chains10.4.2.1. X.509: Certification Signature Chains10.4.2.2. PGP Certificate Signature Chains10.4.3. Summary10.5. Storing and Revoking Keys10.5.1. Key Storage10.5.1.1. Key Escrow10.5.1.2. Key Escrow System and the Clipper Chip10.5.1.3. The Yaksha Security System10.5.1.4. Other Approaches10.5.2. Key Revocation10.6. Digital Signatures10.6.1. Classical Signatures10.6.2. Public Key Signatures10.6.2.1. RSA Digital Signatures10.6.2.2. El Gamal Digital Signature10.7. Summary10.8. Research Issues10.9. Further Reading10.10. Exercises
11. Cipher Techniques
11.1. Problems11.1.1. Precomputing the Possible Messages11.1.2. Misordered Blocks11.1.3. Statistical Regularities11.1.4. Summary11.2. Stream and Block Ciphers11.2.1. Stream Ciphers11.2.1.1. Synchronous Stream Ciphers11.2.1.2. Self-Synchronous Stream Ciphers11.2.2. Block Ciphers11.2.2.1. Multiple Encryption11.3. Networks and Cryptography11.4. Example Protocols11.4.1. Secure Electronic Mail: PEM11.4.1.1. Design Principles11.4.1.2. Basic Design11.4.1.3. Other Considerations11.4.1.4. Conclusion11.4.2. Security at the Transport Layer: SSL11.4.2.1. Supporting Cryptographic Mechanisms11.4.2.2. Lower Layer: SSL Record Protocol11.4.2.3. Upper Layer: SSL Handshake Protocol11.4.2.4. Upper Layer: SSL Change Cipher Spec Protocol11.4.2.5. Upper Layer: SSL Alert Protocol11.4.2.6. Upper Layer: Application Data Protocol11.4.2.7. Summary11.4.3. Security at the Network Layer: IPsec11.4.3.1. IPsec Architecture11.4.3.2. Authentication Header Protocol11.4.3.3. Encapsulating Security Payload Protocol11.4.4. Conclusion11.5. Summary11.6. Research Issues11.7. Further Reading11.8. Exercises
12. Authentication
12.1. Authentication Basics12.2. Passwords12.2.1. Attacking a Password System12.2.2. Countering Password Guessing12.2.2.1. Random Selection of Passwords12.2.2.2. Pronounceable and Other Computer-Generated Passwords12.2.2.3. User Selection of Passwords12.2.2.4. Reusable Passwords and Dictionary Attacks12.2.2.5. Guessing Through Authentication Functions12.2.3. Password Aging12.3. Challenge-Response12.3.1. Pass Algorithms12.3.2. One-Time Passwords12.3.3. Hardware-Supported Challenge-Response Procedures12.3.4. Challenge-Response and Dictionary Attacks12.4. Biometrics12.4.1. Fingerprints12.4.2. Voices12.4.3. Eyes12.4.4. Faces12.4.5. Keystrokes12.4.6. Combinations12.4.7. Caution12.5. Location12.6. Multiple Methods12.7. Summary12.8. Research Issues12.9. Further Reading12.10. Exercises
5. Implementation II: Systems
13. Design Principles
13.1. Overview13.2. Design Principles13.2.1. Principle of Least Privilege13.2.2. Principle of Fail-Safe Defaults13.2.3. Principle of Economy of Mechanism13.2.4. Principle of Complete Mediation13.2.5. Principle of Open Design13.2.6. Principle of Separation of Privilege13.2.7. Principle of Least Common Mechanism13.2.8. Principle of Psychological Acceptability13.3. Summary13.4. Research Issues13.5. Further Reading13.6. Exercises
14. Representing Identity
14.1. What Is Identity?14.2. Files and Objects14.3. Users14.4. Groups and Roles14.5. Naming and Certificates14.5.1. Conflicts14.5.2. The Meaning of the Identity14.5.3. Trust14.6. Identity on the Web14.6.1. Host Identity14.6.1.1. Static and Dynamic Identifiers14.6.1.2. Security Issues with the Domain Name Service14.6.2. State and Cookies14.6.3. Anonymity on the Web14.6.3.1. Anonymity for Better or Worse14.7. Summary14.8. Research Issues14.9. Further Reading14.10. Exercises
15. Access Control Mechanisms
15.1. Access Control Lists15.1.1. Abbreviations of Access Control Lists15.1.2. Creation and Maintenance of Access Control Lists15.1.2.1. Which Subjects Can Modify an Object's ACL?15.1.2.2. Do the ACLs Apply to a Privileged User?15.1.2.3. Does the ACL Support Groups and Wildcards?15.1.2.4. Conflicts15.1.2.5. ACLs and Default Permissions15.1.3. Revocation of Rights15.1.4. Example: Windows NT Access Control Lists15.2. Capabilities15.2.1. Implementation of Capabilities15.2.2. Copying and Amplifying Capabilities15.2.3. Revocation of Rights15.2.4. Limits of Capabilities15.2.5. Comparison with Access Control Lists15.3. Locks and Keys15.3.1. Type Checking15.3.2. Sharing Secrets15.4. Ring-Based Access Control15.5. Propagated Access Control Lists15.6. Summary15.7. Research Issues15.8. Further Reading15.9. Exercises
16. Information Flow
16.1. Basics and Background16.1.1. Entropy-Based Analysis16.1.2. Information Flow Models and Mechanisms16.2. Nonlattice Information Flow Policies16.2.1. Confinement Flow Model16.2.2. Transitive Nonlattice Information Flow Policies16.2.3. Nontransitive Information Flow Policies16.3. Compiler-Based Mechanisms16.3.1. Declarations16.3.2. Program Statements16.3.2.1. Assignment Statements16.3.2.2. Compound Statements16.3.2.3. Conditional Statements16.3.2.4. Iterative Statements16.3.2.5. Goto Statements16.3.2.6. Procedure Calls16.3.3. Exceptions and Infinite Loops16.3.4. Concurrency16.3.5. Soundness16.4. Execution-Based Mechanisms16.4.1. Fenton's Data Mark Machine16.4.2. Variable Classes16.5. Example Information Flow Controls16.5.1. Security Pipeline Interface16.5.2. Secure Network Server Mail Guard16.6. Summary16.7. Research Issues16.8. Further Reading16.9. Exercises
17. Confinement Problem
17.1. The Confinement Problem17.2. Isolation17.2.1. Virtual Machines17.2.2. Sandboxes17.3. Covert Channels17.3.1. Detection of Covert Channels17.3.1.1. Noninterference17.3.1.2. The Shared Resource Matrix Methodology17.3.1.3. Information Flow Analysis17.3.1.4. Covert Flow Trees17.3.2. Analysis of Covert Channels17.3.2.1. Covert Channel Capacity and Noninterference17.3.2.2. Measuring Covert Channel Capacity17.3.2.3. Analyzing a Noisy Covert Channel's Capacity17.3.3. Mitigation of Covert Channels17.4. Summary17.5. Research Issues17.6. Further Reading17.7. Exercises
6. Assurance
18. Introduction to Assurance
18.1. Assurance and Trust18.1.1. The Need for Assurance18.1.2. The Role of Requirements in Assurance18.1.3. Assurance Throughout the Life Cycle18.2. Building Secure and Trusted Systems18.2.1. Life Cycle18.2.1.1. Conception18.2.1.2. Manufacture18.2.1.3. Deployment18.2.1.4. Fielded Product Life18.2.2. The Waterfall Life Cycle Model18.2.2.1. Requirements Definition and Analysis18.2.2.2. System and Software Design18.2.2.3. Implementation and Unit Testing18.2.2.4. Integration and System Testing18.2.2.5. Operation and Maintenance18.2.2.6. Discussion18.2.3. Other Models of Software Development18.2.3.1. Exploratory Programming18.2.3.2. Prototyping18.2.3.3. Formal Transformation18.2.3.4. System Assembly from Reusable Components18.2.3.5. Extreme Programming18.3. Summary18.4. Research Issues18.5. Further Reading18.6. Exercises
19. Building Systems with Assurance
19.1. Assurance in Requirements Definition and Analysis19.1.1. Threats and Security Objectives19.1.2. Architectural Considerations19.1.2.1. Security Mechanisms and Layered Architecture19.1.2.2. Building Security In or Adding Security Later19.1.3. Policy Definition and Requirements Specification19.1.4. Justifying Requirements19.2. Assurance During System and Software Design19.2.1. Design Techniques That Support Assurance19.2.2. Design Document Contents19.2.2.1. Security Functions Summary Specification19.2.2.2. External Functional Specification19.2.2.3. Internal Design Description19.2.2.4. Internal Design Specification19.2.3. Building Documentation and Specifications19.2.3.1. Modification Specifications19.2.3.2. Security Specifications19.2.3.3. Formal Specifications19.2.4. Justifying That Design Meets Requirements19.2.4.1. Requirements Tracing and Informal Correspondence19.2.4.2. Informal Arguments19.2.4.3. Formal Methods: Proof Techniques19.2.4.4. Review19.3. Assurance in Implementation and Integration19.3.1. Implementation Considerations That Support Assurance19.3.2. Assurance Through Implementation Management19.3.3. Justifying That the Implementation Meets the Design19.3.3.1. Security Testing19.3.3.2. Security Testing Using PGWGTest MatricesTest AssertionsTest Specifications19.3.3.3. Formal Methods: Proving That Programs Are Correct19.4. Assurance During Operation and Maintenance19.5. Summary19.6. Research Issues19.7. Further Reading19.8. Exercises
20. Formal Methods
20.1. Formal Verification Techniques20.2. Formal Specification20.3. Early Formal Verification Techniques20.3.1. The Hierarchical Development Methodology20.3.1.1. Verification in HDM20.3.1.2. The Boyer-Moore Theorem Prover20.3.2. Enhanced HDM20.3.3. The Gypsy Verification Environment20.3.3.1. The Gypsy Language20.3.3.2. The Bledsoe Theorem Prover20.4. Current Verification Systems20.4.1. The Prototype Verification System20.4.1.1. The PVS Specification Language20.4.1.2. The PVS Proof Checker20.4.1.3. Experience with PVS20.4.2. The Symbolic Model Verifier20.4.2.1. The SMV Language20.4.2.2. The SMV Proof Theory20.4.2.3. SMV Experience20.4.3. The Naval Research Laboratory Protocol Analyzer20.4.3.1. NPA Languages20.4.3.2. NPA Experience20.5. Summary20.6. Research Issues20.7. Further Reading20.8. Exercises
21. Evaluating Systems
21.1. Goals of Formal Evaluation21.1.1. Deciding to Evaluate21.1.2. Historical Perspective of Evaluation Methodologies21.2. TCSEC: 1983–199921.2.1. TCSEC Requirements21.2.1.1. TCSEC Functional Requirements21.2.1.2. TCSEC Assurance Requirements21.2.2. The TCSEC Evaluation Classes21.2.3. The TCSEC Evaluation Process21.2.4. Impacts21.2.4.1. Scope Limitations21.2.4.2. Process Limitations21.2.4.3. Contributions21.3. International Efforts and the ITSEC: 1991–200121.3.1. ITSEC Assurance Requirements21.3.1.1. Requirements in the TCSEC Not Found in the ITSEC21.3.1.2. Requirements in the ITSEC Not Found in the TCSEC21.3.2. The ITSEC Evaluation Levels21.3.3. The ITSEC Evaluation Process21.3.4. Impacts21.3.4.1. Vendor-Provided Security Targets21.3.4.2. Process Limitations21.4. Commercial International Security Requirements: 199121.4.1. CISR Requirements21.4.2. Impacts21.5. Other Commercial Efforts: Early 1990s21.6. The Federal Criteria: 199221.6.1. FC Requirements21.6.2. Impacts21.7. FIPS 140: 1994–Present21.7.1. FIPS 140 Requirements21.7.2. FIPS 140-2 Security Levels21.7.3. Impact21.8. The Common Criteria: 1998–Present21.8.1. Overview of the Methodology21.8.2. CC Requirements21.8.3. CC Security Functional Requirements21.8.4. Assurance Requirements21.8.5. Evaluation Assurance Levels21.8.6. Evaluation Process21.8.7. Impacts21.8.8. Future of the Common Criteria21.8.8.1. Interpretations21.8.8.2. Assurance Class AMA and Family ALC_FLR21.8.8.3. Products Versus Systems21.8.8.4. Protection Profiles and Security Targets21.8.8.5. Assurance Class AVA21.8.8.6. EAL521.9. SSE-CMM: 1997–Present21.9.1. The SSE-CMM Model21.9.2. Using the SSE-CMM21.10. Summary21.11. Research Issues21.12. Further Reading21.13. Exercises
7. Special Topics
22. Malicious Logic
22.1. Introduction22.2. Trojan Horses22.3. Computer Viruses22.3.1. Boot Sector Infectors22.3.2. Executable Infectors22.3.3. Multipartite Viruses22.3.4. TSR Viruses22.3.5. Stealth Viruses22.3.6. Encrypted Viruses22.3.7. Polymorphic Viruses22.3.8. Macro Viruses22.4. Computer Worms22.5. Other Forms of Malicious Logic22.5.1. Rabbits and Bacteria22.5.2. Logic Bombs22.6. Theory of Malicious Logic22.6.1. Theory of Computer Viruses22.7. Defenses22.7.1. Malicious Logic Acting as Both Data and Instructions22.7.2. Malicious Logic Assuming the Identity of a User22.7.2.1. Information Flow Metrics22.7.2.2. Reducing the Rights22.7.2.3. Sandboxing22.7.3. Malicious Logic Crossing Protection Domain Boundaries by Sharing22.7.4. Malicious Logic Altering Files22.7.5. Malicious Logic Performing Actions Beyond Specification22.7.5.1. Proof-Carrying Code22.7.6. Malicious Logic Altering Statistical Characteristics22.7.7. The Notion of Trust22.8. Summary22.9. Research Issues22.10. Further Reading22.11. Exercises
23. Vulnerability Analysis
23.1. Introduction23.2. Penetration Studies23.2.1. Goals23.2.2. Layering of Tests23.2.3. Methodology at Each Layer23.2.4. Flaw Hypothesis Methodology23.2.4.1. Information Gathering and Flaw Hypothesis23.2.4.2. Flaw Testing23.2.4.3. Flaw Generalization23.2.4.4. Flaw Elimination23.2.5. Example: Penetration of the Michigan Terminal System23.2.6. Example: Compromise of a Burroughs System23.2.7. Example: Penetration of a Corporate Computer System23.2.8. Example: Penetrating a UNIX System23.2.9. Example: Penetrating a Windows NT System23.2.10. Debate23.2.11. Conclusion23.3. Vulnerability Classification23.3.1. Two Security Flaws23.4. Frameworks23.4.1. The RISOS Study23.4.1.1. The Flaw Classes23.4.1.2. Legacy23.4.2. Protection Analysis Model23.4.2.1. The Flaw Classes23.4.2.2. Analysis Procedure23.4.2.3. Legacy23.4.3. The NRL Taxonomy23.4.3.1. The Flaw Classes23.4.3.2. Legacy23.4.4. Aslam's Model23.4.4.1. The Flaw Classes23.4.4.2. Legacy23.4.5. Comparison and Analysis23.4.5.1. The xterm Log File Flaw23.4.5.2. The fingerd Buffer Overflow Flaw23.4.5.3. Summary23.5. Gupta and Gligor's Theory of Penetration Analysis23.5.1. The Flow-Based Model of Penetration Analysis23.5.2. The Automated Penetration Analysis Tool23.5.3. Discussion23.6. Summary23.7. Research Issues23.8. Further Reading23.9. Exercises
24. Auditing
24.1. Definitions24.2. Anatomy of an Auditing System24.2.1. Logger24.2.2. Analyzer24.2.3. Notifier24.3. Designing an Auditing System24.3.1. Implementation Considerations24.3.2. Syntactic Issues24.3.3. Log Sanitization24.3.4. Application and System Logging24.4. A Posteriori Design24.4.1. Auditing to Detect Violations of a Known Policy24.4.1.1. State-Based Auditing24.4.1.2. Transition-Based Auditing24.4.2. Auditing to Detect Known Violations of a Policy24.5. Auditing Mechanisms24.5.1. Secure Systems24.5.2. Nonsecure Systems24.6. Examples: Auditing File Systems24.6.1. Audit Analysis of the NFS Version 2 Protocol24.6.2. The Logging and Auditing File System (LAFS)24.6.3. Comparison24.7. Audit Browsing24.8. Summary24.9. Research Issues24.10. Further Reading24.11. Exercises
25. Intrusion Detection
25.1. Principles25.2. Basic Intrusion Detection25.3. Models25.3.1. Anomaly Modeling25.3.1.1. Derivation of Statistics25.3.2. Misuse Modeling25.3.3. Specification Modeling25.3.4. Summary25.4. Architecture25.4.1. Agent25.4.1.1. Host-Based Information Gathering25.4.1.2. Network-Based Information Gathering25.4.1.3. Combining Sources25.4.2. Director25.4.3. Notifier25.5. Organization of Intrusion Detection Systems25.5.1. Monitoring Network Traffic for Intrusions: NSM25.5.2. Combining Host and Network Monitoring: DIDS25.5.3. Autonomous Agents: AAFID25.6. Intrusion Response25.6.1. Incident Prevention25.6.2. Intrusion Handling25.6.2.1. Containment Phase25.6.2.2. Eradication Phase25.6.2.3. Follow-Up Phase25.7. Summary25.8. Research Issues25.9. Further Reading25.10. Exercises
8. Practicum
26. Network Security
26.1. Introduction26.2. Policy Development26.2.1. Data Classes26.2.2. User Classes26.2.3. Availability26.2.4. Consistency Check26.3. Network Organization26.3.1. Firewalls and Proxies26.3.2. Analysis of the Network Infrastructure26.3.2.1. Outer Firewall Configuration26.3.2.2. Inner Firewall Configuration26.3.3. In the DMZ26.3.3.1. DMZ Mail Server26.3.3.2. DMZ WWW Server26.3.3.3. DMZ DNS Server26.3.3.4. DMZ Log Server26.3.3.5. Summary26.3.4. In the Internal Network26.3.5. General Comment on Assurance26.4. Availability and Network Flooding26.4.1. Intermediate Hosts26.4.2. TCP State and Memory Allocations26.5. Anticipating Attacks26.6. Summary26.7. Research Issues26.8. Further Reading26.9. Exercises
27. System Security
27.1. Introduction27.2. Policy27.2.1. The Web Server System in the DMZ27.2.2. The Development System27.2.3. Comparison27.2.4. Conclusion27.3. Networks27.3.1. The Web Server System in the DMZ27.3.2. The Development System27.3.3. Comparison27.4. Users27.4.1. The Web Server System in the DMZ27.4.2. The Development System27.4.3. Comparison27.5. Authentication27.5.1. The Web Server System in the DMZ27.5.2. Development Network System27.5.3. Comparison27.6. Processes27.6.1. The Web Server System in the DMZ27.6.2. The Development System27.6.3. Comparison27.7. Files27.7.1. The Web Server System in the DMZ27.7.2. The Development System27.7.3. Comparison27.8. Retrospective27.8.1. The Web Server System in the DMZ27.8.2. The Development System27.9. Summary27.10. Research Issues27.11. Further Reading27.12. Exercises
28. User Security
28.1. Policy28.2. Access28.2.1. Passwords28.2.2. The Login Procedure28.2.2.1. Trusted Hosts28.2.3. Leaving the System28.3. Files and Devices28.3.1. Files28.3.1.1. File Permissions on Creation28.3.1.2. Group Access28.3.1.3. File Deletion28.3.2. Devices28.3.2.1. Writable Devices28.3.2.2. Smart Terminals28.3.2.3. Monitors and Window Systems28.4. Processes28.4.1. Copying and Moving Files28.4.2. Accidentally Overwriting Files28.4.3. Encryption, Cryptographic Keys, and Passwords28.4.4. Start-up Settings28.4.5. Limiting Privileges28.4.6. Malicious Logic28.5. Electronic Communications28.5.1. Automated Electronic Mail Processing28.5.2. Failure to Check Certificates28.5.3. Sending Unexpected Content28.6. Summary28.7. Research Issues28.8. Further Reading28.9. Exercises
29. Program Security
29.1. Introduction29.2. Requirements and Policy29.2.1. Requirements29.2.2. Threats29.2.2.1. Group 1: Unauthorized Users Accessing Role Accounts29.2.2.2. Group 2: Authorized Users Accessing Role Accounts29.2.2.3. Summary29.3. Design29.3.1. Framework29.3.1.1. User Interface29.3.1.2. High-Level Design29.3.2. Access to Roles and Commands29.3.2.1. Interface29.3.2.2. Internals29.3.2.3. Storage of the Access Control Data29.4. Refinement and Implementation29.4.1. First-Level Refinement29.4.2. Second-Level Refinement29.4.3. Functions29.4.3.1. Obtaining Location29.4.3.2. The Access Control Record29.4.3.3. Error Handling in the Reading and Matching Routines29.4.4. Summary29.5. Common Security-Related Programming Problems29.5.1. Improper Choice of Initial Protection Domain29.5.1.1. Process Privileges29.5.1.2. Access Control File Permissions29.5.1.3. Memory Protection29.5.1.4. Trust in the System29.5.2. Improper Isolation of Implementation Detail29.5.2.1. Resource Exhaustion and User Identifiers29.5.2.2. Validating the Access Control Entries29.5.2.3. Restricting the Protection Domain of the Role Process29.5.3. Improper Change29.5.3.1. Memory29.5.3.2. Changes in File Contents29.5.3.3. Race Conditions in File Accesses29.5.4. Improper Naming29.5.5. Improper Deallocation or Deletion29.5.6. Improper Validation29.5.6.1. Bounds Checking29.5.6.2. Type Checking29.5.6.3. Error Checking29.5.6.4. Checking for Valid, not Invalid, Data29.5.6.5. Checking Input29.5.6.6. Designing for Validation29.5.7. Improper Indivisibility29.5.8. Improper Sequencing29.5.9. Improper Choice of Operand or Operation29.5.10. Summary29.6. Testing, Maintenance, and Operation29.6.1. Testing29.6.1.1. Testing the Module29.6.2. Testing Composed Modules29.6.3. Testing the Program29.7. Distribution29.8. Conclusion29.9. Summary29.10. Research Issues29.11. Further Reading29.12. Exercises
9. End Matter
30. Lattices
30.1. Basics30.2. Lattices30.3. Exercises
31. The Extended Euclidean Algorithm
31.1. The Euclidean Algorithm31.2. The Extended Euclidean Algorithm31.3. Solving ax mod n = 131.4. Solving ax mod n = b31.5. Exercises
32. Entropy and Uncertainty
32.1. Conditional and Joint Probability32.2. Entropy and Uncertainty32.3. Joint and Conditional Entropy32.3.1. Joint Entropy32.3.2. Conditional Entropy32.3.3. Perfect Secrecy32.4. Exercises
33. Virtual Machines
33.1. Virtual Machine Structure33.2. Virtual Machine Monitor33.2.1. Privilege and Virtual Machines33.2.2. Physical Resources and Virtual Machines33.2.3. Paging and Virtual Machines33.3. Exercises
34. Symbolic Logic
34.1. Propositional Logic34.1.1. Natural Deduction in Propositional Logic34.1.1.1. Rules34.1.1.2. Derived Rules34.1.2. Well-Formed Formulas34.1.3. Truth Tables34.1.4. Mathematical Induction34.2. Predicate Logic34.2.1. Natural Deduction in Predicate Logic34.3. Temporal Logic Systems34.3.1. Syntax of CTL34.3.2. Semantics of CTL34.4. Exercises
35. Example Academic Security Policy
35.1. University of California E-mail Policy35.1.1. Summary: E-mail Policy Highlights35.1.1.1. Cautions35.1.1.2. Do35.1.1.3. Do Not35.1.1.4. Does This Policy Apply to You?35.1.2. University of California Electronic Mail Policy35.1.2.1. Introduction35.1.2.2. Purpose35.1.2.3. Definitions35.1.2.4. Scope35.1.2.5. General Provisions35.1.2.6. Specific ProvisionsA. Allowable UseB. Security and ConfidentialityC. Archiving and Retention35.1.2.7. Policy Violations35.1.2.8. Responsibility for Policy35.1.2.9. Campus Responsibilities and Discretion35.1.2.10. Appendix A—Definitions35.1.2.11. Appendix B—References35.1.2.12. Appendix C—Policies Relating to Nonconsensual Access35.1.3. UC Davis Implementation of the Electronic Mail Policy35.1.3.1. Purpose and Scope35.1.3.2. Definitions35.1.3.3. PolicyA. Allowable UsersB. Allowable UsesC. Termination of AffiliationD. Service RestrictionsE. Inspection, Monitoring, or DisclosureF. Administrative RecordsG. Postmaster ProceduresH. Backup PracticesI. Notification of Policy35.1.4. References and Related Policy35.2. The Acceptable Use Policy for the University of California, Davis35.2.1. Part I35.2.1.1. Introduction35.2.1.2. Rights and Responsibilities35.2.1.3. Existing Legal Context35.2.1.4. Enforcement35.2.2. Part II
Bibliography

Content preview from Computer Security: Art and Science

Chapter 9. Basic Cryptography

	YORK: Then, York, be still awhile, till time do serve:Watch thou and wake when others be asleep,To pry into the secrets of the state;
	--The Second Part of King Henry the Sixth, I, i, 249–260.

Cryptography is a deep mathematical subject. Because this book focuses on system security, we view cryptography as a supporting tool. Viewed in this context, the reader needs only a brief overview of the major points of cryptography relevant to that use. This chapter provides such an overview.

Cryptographic protocols provide a cornerstone for secure communication. These protocols are built on ideas presented in this chapter and are discussed at length later on.

What Is Cryptography?

The word cryptography comes from two Greek words ...

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Computer Security Art and Science, 2nd Edition

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Computer Security: Art and Science

by Matt Bishop

Chapter 9. Basic Cryptography

What Is Cryptography?

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