1. Authoritative Technical Sources

• RFC 5280 for X.509 certificate and CRL profiles
• CA/Browser Forum Baseline Requirements for publicly trusted TLS certificates
• NIST SP 800-57 for key-management recommendations

2. Workshop Mapping

3. Boundaries

This workshop does not replace WebTrust, ETSI, organization-specific audits, or CA/Browser Forum compliance work. Public CAs must check their currently applicable requirements themselves.

Sources and Further References

• RFC 5280: https://datatracker.ietf.org/doc/html/rfc5280
• CA/Browser Forum Baseline Requirements: https://cabforum.org/working-groups/server/baseline-requirements/requirements/
• CA/Browser Forum TLS BR Documents: https://cabforum.org/working-groups/server/baseline-requirements/documents/
• NIST SP 800-57 Part 1 Rev. 5: https://csrc.nist.gov/pubs/sp/800/57/pt1/r5/final
• NIST SP 800-57 Rev. 6 Initial Public Draft: https://csrc.nist.gov/pubs/sp/800/57/pt1/r6/ipd
• OpenSSL Documentation: https://docs.openssl.org/
• OpenSSL ca: https://docs.openssl.org/3.0/man1/openssl-ca/
• OpenSSL x509: https://docs.openssl.org/3.0/man1/openssl-x509/
• Let's Encrypt Documentation: https://letsencrypt.org/docs/
• HashiCorp Vault PKI Secrets Engine: https://developer.hashicorp.com/vault/docs/secrets/pki
• cert-manager Documentation: https://cert-manager.io/docs/
• Smallstep Documentation: https://smallstep.com/docs/

Practice Appendix: CA Evidence for this Assessment

This appendix makes the file more complete as workshop material: it connects the topic with repeatable evidence, review questions, operational decisions and security expectations. The points are not invented product features; they are real review criteria for PKI work with X.509, OpenSSL and common CA operating models.

A.1 Scope and Boundary

Every CA task starts by separating a private lab PKI, an internal enterprise PKI and publicly trusted server certificates. That distinction changes responsibilities, audit requirements, validity periods, revocation handling and which clients may trust the certificate.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.2 Trust Model

The trust model states which root is distributed as trust anchor, which intermediates may sign and which relying parties evaluate the chain. Without that model a technically valid certificate can still be operationally unclear.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.3 Root CA Handling

A root CA is a local learning artifact in this workshop. In real environments the root key is kept offline or in an HSM and controlled through ceremonies, separated roles, logs and recovery plans.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.4 Intermediate CA Operations

Intermediate CAs are the operational signing layer. Their certificates need CA:TRUE, keyCertSign, cRLSign, suitable path length constraints and a clear lifecycle and rotation plan.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.5 Registration Authority

The RA or approval function decides whether a request may be signed. For internal servers this means at least system owner, DNS name, environment, purpose, lifetime, responsible team and change window are traceable.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.6 Private Key Protection

Private keys are the most sensitive PKI asset. Repositories should contain configurations, CSRs, public certificates and evidence only. Keys are created below work/ in labs or in protected systems and are not committed.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.7 CSR Review

A CSR proves possession of a private key, but not authorization for a name. Review the subject, SANs, public key algorithm, key size, requester and intended certificate type.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.8 X.509 Extensions

Extensions are security logic, not decoration. Basic constraints, key usage, extended key usage, subject alternative name, subject key identifier and authority key identifier define what a certificate may be accepted for.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.9 SAN and Naming Model

Server identity is checked through SANs. The common name alone is not sufficient for modern hostname verification. Internal namespaces, documentation domains and production domains must remain separate.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.10 Chain Verification

A reliable check separates trust anchor and chain certificates. In practice: root through -CAfile, intermediate through -untrusted, leaf as the target certificate and hostname verification where needed.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.11 Revocation

Revocation is an operating process, not an afterthought. CRL or OCSP data must be produced, published, monitored and actually consumed by relevant clients.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.12 Expiry and Renewal

Certificates need a renewal window before they become critical. The decision covers a new serial, new signature, optionally a new key, rollout order and rollback plan.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.13 Automation

Automation through Vault PKI, cert-manager, ACME, Smallstep or SPIFFE reduces manual work, but does not replace policy. Roles, TTLs, issuers, approvers and audit remain explicit.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.14 Audit and Evidence

Evidence must show what was created, checked and approved. Good evidence contains OpenSSL output, fingerprints, serial numbers, chain verification, CRL or OCSP status and no secrets.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.15 Incident Response

For key compromise the order matters: identify affected serials, revoke, update CRL or OCSP, issue replacements, notify operators, preserve logs and document the root cause.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.16 Policy and CPS

A Certificate Policy describes what is allowed. A Certification Practice Statement describes how it is operated. Even private PKIs benefit from this separation because it stabilizes review and operations.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.17 Environment

WSL, VMs, bare metal and cloud differ in trust store behavior, file permissions, package versions and paths. Commands and evidence must therefore name the local environment.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.18 Security Hardening

Hardening covers file permissions, separated roles, short lifetimes, minimal EKUs, safe algorithms, offline root, controlled intermediates and monitoring for expiry or unusual issuance.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.19 Troubleshooting

PKI troubleshooting starts with the chain: does the private key match, is the CSR correct, was the certificate signed correctly, is the chain complete and does the client trust the root?

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.20 Team Workflow

In workshops and real teams one person should create, a second person should review and a third person should be able to reproduce the evidence. This makes PKI mistakes visible earlier.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.21 Submission Format

A solid submission contains configuration, public artifacts, evidence, failure analysis, cleanup notes and a short operational assessment. Private keys and production data are intentionally absent.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.22 Production Transfer

Moving from lab to production is not copying OpenSSL commands. It requires roles, safe key storage, monitoring, backup, revocation distribution, documentation and regularly practiced recovery.

Concrete review questions:

• Which entity is protected or signed?
• Which file or output backs the statement?
• Which role is played by the root, intermediate, leaf or client?
• Which assumption needs additional production review?
• Which change must be traceable in audit?
• Which cleanup or protection step prevents accidental secret leaks?

A.23 Minimal Evidence Set

evidence/
  context.md
  openssl-version.txt
  csr-review.txt
  certificate-summary.txt
  certificate-extensions.txt
  chain-verification.txt
  revocation-or-renewal-note.md
  cleanup.md

This set is intentionally minimal. Advanced exercises add CA database state, CRL, OCSP response, audit log, policy excerpt, role decision and incident timeline.

A.24 Quality Criteria

• The technical scope is clear before execution.
• The chain is technically verified, not only described.
• SAN, key usage, EKU and basic constraints are explicitly evaluated.
• Revocation and renewal are covered as lifecycle concerns.
• Private keys stay outside versioned content.
• Public standards are separated correctly: RFC 5280 describes profile and processing, the CA/Browser Forum governs publicly trusted server certificates, and NIST SP 800-57 informs key management and lifetimes.