Understanding PKI

Carlisle Adams is recognized internationally for his many contributions to the design, specification, and standardization of public-key infrastructures. He is senior cryptographer and principal of security at Entrust, Inc. He has been an active participant in the IETF Public-Key Infrastructure X.509 (PKIX) and Common Authentication Technology (CAT) working groups. Steve Lloyd has more than 20 years experience in data communications and distributed systems security. His areas of expertise include distributed message handling systems and directory services, TCP/IP, security protocols, security architectures, and large-scale Public-Key Infrastructure policy and technology. He is currently manager of IT security consulting at AEPOS Technologies Corporation. 0672323915AB10042002

Foreword.


Preface.


About the Authors.
I. CONCEPTS.

1. Introduction.
2. Public-Key Cryptography.


Symmetric versus Asymmetric Ciphers.



Secret Key.



New Directions: Public Key.



Public/Private-Key Pair.



Services of Public-Key Cryptography.



Security between Strangers.



Encryption.



Digital Signature.



Data Integrity.



Key Establishment.



Other Services.



Algorithms.



RSA.



DSA.



DH.



ECDSA and ECDH.



SHA-1.



Ongoing Work.



Summary.

3. The Concept of an Infrastructure.


Pervasive Substrate.



Application Enabler.



Secure Sign-On.



End-User Transparency.



Comprehensive Security.



Business Drivers.



Public-Key Infrastructure Defined.



Certification Authority.



Certificate Repository.



Certificate Revocation.



Key Backup and Recovery.



Automatic Key Update.



Key History.



Cross-Certification.



Support for Non-repudiation.



Time Stamping.



Client Software.



Summary.

4. Core PKI Services: Authentication, Integrity, and Confidentiality.


Definitions.



Authentication.



Integrity.



Confidentiality.



Mechanisms.



Authentication.



Integrity.



Confidentiality.



Operational Considerations.



Performance.



Online versus Offline Operation.



Commonality of Underlying Algorithms.



Entity Naming.



Summary.

5. PKI-Enabled Services.


Secure Communication.



Secure Time Stamping.



Notarization.



Non-repudiation.



Connection with Other Services.



Need for Secure Data Archive.



Complexity of This Service.



The Human Factor.



Privilege Management.



Authentication and Authorization.



Authorization Authorities.



Delegation.



Connection with the PKI.



Privacy.



Mechanisms Required to Create PKI-Enabled Services.



Digital Signatures, Hashes, MACs, and Ciphers.



Trusted Time Sources.



Privilege Policy Creation Mechanism.



Privilege Policy Processing Engines.



Privilege Management Infrastructure Mechanisms.



Privacy Architecture.



Operational Considerations.



Trusted Time Delivery Mechanism.



Secure Protocols.



Server Redundancy.



Physically Secure Archive Facilities.



Privacy Certificates and Identity Mapping.



Real Life.



Comprehensive PKI and Current Practice.



Summary.

6. Certificates and Certification.


Certificates.



Digital Certificate.



Certificate Structure and Semantics.



Alternative Certificate Formats.



Certificate Policies.



Object Identifiers.



Policy Authorities.



Certification Authority.



Registration Authority.



Summary.

7. Key and Certificate Management.


Key/Certificate Life-Cycle Management.



Initialization Phase.



Issued Phase.



Cancellation Phase.



Summary.

8. Certificate Revocation.


Periodic Publication Mechanisms.



Certificate Revocation Lists (CRLs).



Complete CRLs.



Certification Authority Revocation Lists (CARLs).



End-Entity Public-Key Certification Revocation Lists (EPRLs).



CRL Distribution Points.



Redirect CRLs.



Delta and Indirect Delta CRLs.



Indirect CRLs.



Certificate Revocation Trees (CRTs).



Online Query Mechanisms.



Online Certificate Status Protocol (OCSP).



Simple Certificate Validation Protocol (SCVP).



Other Revocation Options.



Performance, Scalability, and Timeliness.



Summary.

9. Trust Models.


Strict Hierarchy of Certification Authorities.



Loose Hierarchy of Certification Authorities.



Policy-Based Hierarchies.



Distributed Trust Architecture.



Mesh Configuration.



Hub-and-Spoke Configuration.



Four-Corner Trust Model.



Web Model.



User-Centric Trust.



Cross-Certification.



Entity Naming.



Certificate Path Processing.



Path Construction.



Path Validation.



Trust Anchor Considerations.



Summary.

10. Multiple Certificates per Entity.


Multiple Key Pairs.



Key Pair Uses.



Relationship between Key Pairs and Certificates.



Real-World Difficulties.



Independent Certificate Management.



Support for Non-repudiation.



Summary.

11. PKI Information Dissemination: Repositories and Other Techniques.


Private Dissemination.



Publication and Repositories.



Locating Repositories 162Tradeoffs.



Interdomain Repository Issues and Options.



Direct Access.



Border Repository.



Shared Repository.



Interdomain Replication.



In-band Protocol Exchange.



Summary.

12. PKI Operational Considerations.


Client-Side Software.



Off-line Operations.



Physical Security.



Hardware Components.



User Key Compromise.



Disaster Preparation and Recovery.



Relying Party Notification.



Preparation.



Recovery.



Additional Observations.



Summary.

13. Electronic Signature Legislation and Considerations.


Electronic Signature Legislation.



E-Sign.



Digital Signatures in Context.



EU Electronic Signature Directive.



The Significance of Electronic Signature Initiatives.



Legal Considerations for PKIs.



CA Requirements.



Roles and Responsibilities.



Private Enterprise PKIs.



Other Contractual-Based Frameworks.



Confidentiality.



Summary.

14. PKI in Practice.


What PKI Does.



What PKI Does Not Do.



The Value of PKI.



When Certificates and People Meet.



An E-mail Scenario.



A Web Scenario.



Summary.

15. The Future of PKI.


What Happened?



How the World Is Changing.



A Recognized Authoritative Body.



A Motivation.



Users.



Reasons for Cautious Optimism.



Summary.

16. Conclusions and Further Reading.


Conclusions.



Suggestions for Further Reading.

II. STANDARDS.

17. Introduction.
18. Major Standards Activities.


X.509.



PKIX.



X.500.



LDAP.



ISO TC68.



ANSI X9F.



S/MIME.



IPsec.



TLS.



SPKI.



OpenPGP.



EDIFACT.



IEEE.



WAP.



XML-Based Activities.



Other Activities.



U.S. FPKI.



MISPC.



GOC PKI.



SET.



SEMPER.



ECOM.



JCP.



ICE-CAR.



Summary.

19. Standardization Status and Road Map.


Current Standardization Status.



X.509.



PKIX.



X.500.



LDAP.



S/MIME.



IPsec.



TLS.



Toolkit Requirements (APIs and Mechanisms).



Others.



Ongoing Standardization Work.



Summary.

20. Standards: Necessary but Not Sufficient.


The Role of Standards, Profiles, and Interoperability Testing.



Profiles and Interoperability Testing.



Interoperability Initiatives.



Automotive Network eXchange.



Bridge CA Demonstration.



Federal PKI.



Minimum Interoperability Specification.



National Automated Clearing House Association.



PKI X.509.



Securities Industry Root CA Proof of Concept.



EEMA PKI Challenge.



Summary.

21. Conclusions and Further Reading.


Conclusions.



Suggestions for Further Reading.



Certificate/CRL Syntax and Life-Cycle Management Protocols.



Certificate/CRL Storage and Retrieval.



XML-Based Initiatives.



Interoperability Initiatives.



Standards Bodies' Web Sites.



Books.

III. DEPLOYMENT CONSIDERATIONS.

22. Introduction.
23. Benefits and Costs of a PKI.


Business Case Considerations.



Cost Considerations.



Deployment: Now or Later?



Summary.

24. Deployment Issues and Decisions.


Trust Models: Hierarchical versus Distributed.



In-sourcing versus Out-sourcing.



Build versus Buy.



Closed versus Open Environment.



X.509 versus Alternative Certificate Formats.



Targeted Applications versus Comprehensive Solution.



Standard versus Proprietary Solutions.



Interoperability Considerations.



Certificate and CRL Profiles.



Multiple Industry-Accepted Standards.



PKI-Enabled Applications.



Policy/Business Control Issues.



On-line versus Off-line Operations.



Peripheral Support.



Facility Requirements.



Personnel Requirements.



Certificate Revocation.



End-Entity Roaming.



Key Recovery.



Repository Issues.



Disaster Planning and Recovery.



Security Assurance.



Mitigating Risk.



Summary.

25. Barriers to Deployment.


Repository Issues.



Lack of Industry-Accepted Standard.



Multivendor Interoperability.



Scalability and Performance.



Knowledgeable Personnel.



PKI-Enabled Applications.



Corporate-Level Acceptance.



Summary.

26. Typical Business Models.


Internal Communications Business Model.



External Communications Business Model.



Business-to-Business Communication.



Business-to-Consumer Communication.



Internal/External Business Model Hybrids.



Business Model Influences.



Government-Sponsored Initiatives.



Interdomain Trust.



Identrus.



Bridge CA.



VeriSign Trust Network.



GTE CyberTrust/Baltimore Technologies OmniRoot.



Other Trust Networks.



Summary.

27. Conclusions and Further Reading.


Conclusions.



Suggestions for Further Reading.

References.
Index. 0672323915T10162002