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This project aims to develop a comprehensive security evaluation tool for a wide range of Marine Corps PKE applications. The tool will accommodate various security mechanisms and enhance certification path validation logic.
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PKE PPMike Henry Jean Petty EntrustCygnaCom Santosh Chokhani
Briefing Contents • Common Criteria Background • Goals of PKE PP • Assumptions • Approach in Constructing the PP • Summary of Packages • Planned Enhancements
Common Criteria: Sponsors Common to Various Nations: Only charter members shown
Common Criteria: Key Concepts • Protection Profile (PP) • Specification of Security Requirements at what level • Implementation and product neutral • Security Target (ST) • Specification of Security Features at what and how level • Implementation and product specific Target of Evaluation (TOE) Products Evaluated against ST
Common Criteria Standard: Specification Part 1 Introduction PP and ST Contents and Formats Part 2: Security Functional Requirements Select from these for PP and/or ST Can extend the requirements Part 3: Security Assurance Requirements Select from these for PP and/or ST Can extend the requirements
Common Criteria Standards: Other Documents • Common Evaluation Methodology (CEM) • PP Evaluation Standard • ST Evaluation Standard • TOE Evaluation Standard Guide to Writing PP and ST
Common Criteria: Part 2 & Part 3 Hierarchy Part 2 or 3 …… …. Class …….... Family Component …….... …….... Element
Common Criteria: Part 2 (functional) Classes User Data Protection Comm Crypto Audit TSF Protection I&A Security Management Privacy TOE Access Trusted Path Resource Utilization
Common Criteria: Part 3 (assurance) Classes Delivery & Operation Development Configuration Management Guidance Documents Vulnerability Assessments Life-Cycle Support Tests Note: CC also packages assurance requirements in 7 hierarchical packages called Evaluation Assurance Levels (EAL)
Common Criteria: PP Contents TOE Description Introduction Assumptions Threats Organizational Security Policies Security Environment drives Security objectives for TOE Security objectives for environment Security Objectives drives Functional Assurance Security Requirements Rationale
Common Criteria: Functional Package Contents Security objectives drives Functional Security Requirements Rationale
Common Criteria: Evaluation Model PP Evaluation (Internal) ST Evaluation (Internal; Against PP Optional) TOE Evaluation (against ST)
Project Goals • Develop a tool for security evaluation of broad range (all possible!!!) PKE applications in Marine Corps • PKI based cryptographic services vary from application to application • PKE toolkits have varying degree of functionality for certification path validation logic • Accommodate a variety of algorithms • DoD Class 3 • Fortezza Class 4 • KMI • Future enhancements
Assumptions • Need to accommodate COTS products with varying degree of path validation capability • PKI based security mechanisms will vary from application to application • Provide ability to evaluate OCSP and CRL • Extend the CC for certification path validation and other items • Access control components are not appropriate for certification path validation • Existing CC components not appropriate for CRL and OCSP response processing
Challenge: Balancing Act Product Realities Current Implementations Variety of Solutions Planned Enhancements Security Optional Features
Challenge: Requirements and Capability Increasing Security, Functionality, etc. Examples: No trust anchor processing……………………….Full trust anchor processing No policy processing……………………………….Full policy processing
Solutions Use functional packages as needed Example: Policy processing Use “assignment” operation for SFR to provide additional granularity (Example: trust anchor processing)
Approach • Use functional packages to permit ST author to select appropriate: • PKI based cryptographic mechanisms • Certification path validation capability • Revocation checking • Certification path validation rules • Non-procedural • Attempt to preserve X.509 input, processing, output • Policy calculation all in “output”
Approach: Environmental Assumptions • Cryptographic Module • Protects private keys • May protect trust anchors • Performs cryptography • Secure Computing and OS • Protects keys and data • Provides audit capability • Protects audit logs • Optional
Approach • Use mandatory functional package for PKI Credentials • Required to accommodate cases where cryptographic module does not manage trust anchors • Can be met by • application, or • environment • OS, or • Cryptographic module
Approach • Public Key Based Cryptographic Services • Encryption • Authentication • Integrity Association Path Validation Engine Need for PKI Cryptographic Functional Packages
Approach: Handling Lack of Current Revocation Information • Ability to specify acceptance of certification path in case of no revocation information or old revocation information • Past experience shows that flexibility may be needed to provide: • Configurability • User interaction
Functional Packages: Certificate and CRL Full Full Policy CRL Processing Basic Policy Basic OCSP Response Processing • Path Validation • Select one from four hierarchical • Selection based on product capability
Functional Packages: Cryptography Related PKI Credential Management Key Transfer Encryption Key Agreement Encryption Key Transfer Decryption Sign PKI Based Entity Authentication Key Agreement Decryption Verify
Enhancements (made or being made) • PKI Based Entity Authentication Functional Package • Clean up some language and CC dependencies • Add trust anchor processing as optional • Neither X.509 nor PKIX require it • Match issuer and subject DN • Verify signature using subject public key and parameters (if applicable) • Verify validity period • EKU application note may go away when MS makes changes
Enhancements (made or being made) • Optional audit functional package • Optional because many applications may not support auditing, e.g., e-mail client • Will cover only PKE specific event • Will also cover audit review and protection • Some or all of the requirements may be satisfied by the environment
Enhancements (future) • Delta CRL • Partitioned CRL (??) • Support for SCVP and/or OCSP v2 (??)