| name | configuring-certificate-authority-with-openssl |
| description | Build a two-tier PKI Certificate Authority hierarchy (offline Root CA plus issuing Intermediate CA) using OpenSSL and the Python cryptography library, covering certificate extensions, CRL distribution points, OCSP responder configuration, and certificate policy management. Use when standing up an internal CA, issuing or revoking X.509 certificates, or designing PKI trust hierarchies for TLS, code-signing, or client-authentication use cases. |
| domain | cybersecurity |
| subdomain | cryptography |
| tags | ["cryptography","pki","certificate-authority","openssl","x509"] |
| version | 1.0 |
| author | mahipal |
| license | Apache-2.0 |
| nist_csf | ["PR.DS-01","PR.DS-02","PR.DS-10"] |
| mitre_attack | ["T1649","T1553.004","T1557","T1587.003"] |
Configuring Certificate Authority with OpenSSL
Overview
A Certificate Authority (CA) is the trust anchor in a PKI hierarchy, responsible for issuing, signing, and revoking digital certificates. This skill covers building a two-tier CA hierarchy (Root CA + Intermediate CA) using OpenSSL and the Python cryptography library, including CRL distribution, OCSP responder configuration, and certificate policy management.
When to Use
- When deploying or configuring configuring certificate authority with openssl capabilities in your environment
- When establishing security controls aligned to compliance requirements
- When building or improving security architecture for this domain
- When conducting security assessments that require this implementation
Prerequisites
- Familiarity with cryptography concepts and tools
- Access to a test or lab environment for safe execution
- Python 3.8+ with required dependencies installed
- Appropriate authorization for any testing activities
Objectives
- Create a Root CA with self-signed certificate
- Create an Intermediate CA signed by the Root CA
- Issue server and client certificates from the Intermediate CA
- Configure Certificate Revocation Lists (CRLs)
- Implement certificate policies and constraints
- Build a complete PKI hierarchy programmatically
Key Concepts
CA Hierarchy
Root CA (offline, air-gapped)
|
+-- Intermediate CA (online, operational)
|
+-- Server Certificates
+-- Client Certificates
+-- Code Signing Certificates
Certificate Extensions
| Extension | Purpose | Critical |
|---|
| basicConstraints | CA:TRUE/FALSE, pathLenConstraint | Yes |
| keyUsage | keyCertSign, cRLSign, digitalSignature | Yes |
| extendedKeyUsage | serverAuth, clientAuth, codeSigning | No |
| subjectKeyIdentifier | Hash of public key | No |
| authorityKeyIdentifier | Issuer's key identifier | No |
| crlDistributionPoints | URL to CRL | No |
| authorityInfoAccess | OCSP responder URL | No |
Security Considerations
