Listen to this Post
Digital certificates and trust models are foundational concepts in cybersecurity, especially for those pursuing CompTIA Security+. Understanding how these elements work ensures secure communications and verifies the authenticity of entities in a network.
You Should Know:
1. Digital Certificates Overview
Digital certificates are electronic documents that bind a public key to an entity (person, organization, or device). They are issued by Certificate Authorities (CAs) and follow the X.509 standard.
Key Components:
- Subject (Owner’s details)
- Public Key (Used for encryption/verification)
- Issuer (CA that signed the certificate)
- Validity Period (Start and expiration dates)
- Digital Signature (Ensures integrity)
Example OpenSSL Command to View a Certificate:
openssl x509 -in certificate.crt -text -noout
2. Trust Models in PKI
Public Key Infrastructure (PKI) relies on different trust models:
- Single CA Model – One central CA issues all certificates.
- Hierarchical Model – Root CA delegates to intermediate CAs.
- Cross-Certification (Bridge Model) – Multiple CAs trust each other.
- Web of Trust (PGP Model) – Users vouch for each other.
Verify a Certificate Chain:
openssl verify -CAfile root-ca.pem -untrusted intermediate.pem user-cert.pem
3. Certificate Revocation
Certificates can be revoked if compromised. Two main methods:
– Certificate Revocation List (CRL) – A list of revoked certs.
– Online Certificate Status Protocol (OCSP) – Real-time validation.
Check CRL with OpenSSL:
openssl crl -in revoked.crl -text -noout
4. Generating a Self-Signed Certificate (Testing Only)
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
5. Windows Certificate Management
View installed certificates in Windows:
certmgr.msc
Export a certificate:
Export-Certificate -Cert (Get-ChildItem -Path Cert:\LocalMachine\My\<CertificateThumbprint>) -FilePath C:\exported.cer
What Undercode Say
Understanding trust models and digital certificates is crucial for securing communications. PKI ensures authenticity, integrity, and non-repudiation. Always verify certificates, check revocation status, and use strong encryption.
Expected Output:
Certificate: Data: Version: 3 (0x2) Serial Number: 1234abcd... Signature Algorithm: sha256WithRSAEncryption Issuer: C=US, O=Example CA, CN=Example Root CA Validity: Not Before: Jan 1 00:00:00 2023 GMT Not After : Dec 31 23:59:59 2024 GMT Subject: C=US, O=Example Corp, CN=example.com Public Key Algorithm: rsaEncryption RSA Public-Key: (4096 bit) Modulus: 00:aa:bb:cc... Signature Algorithm: sha256WithRSAEncryption 11:22:33:44...
(End of article)
References:
Reported By: Housenathan Security – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
