X.509
Technology & Computing abbreviation · Cybersecurity
| Stands for | X.509 (public key certificate standard) |
|---|---|
| Categories | Technology & Computing |
X.509 stands for X.509 (public key certificate standard), a cybersecurity abbreviation.
The standard format for public key certificates, defining fields such as subject, issuer, validity period, public key and extensions like subject alternative names. TLS, S/MIME email and code-signing certificates all use X.509.
Example: Inspect the X.509 certificate with openssl x509 -text to check the expiry date and SANs.
Usage notes
First published by the ITU-T in 1988 as part of the X.500 directory standards; the internet profile is RFC 5280 (2008). Certificates are commonly stored in PEM (base64 text) or DER (binary) encodings. Version 3, which added extensions, is the one in use today.
Related abbreviations
More cybersecurity abbreviations
- 2FA – Two-factor authentication
- AAA – Authentication, authorization and accounting
- ABAC – Attribute-based access control
- ACL – Access control list
- AES – Advanced Encryption Standard
- APT – Advanced persistent threat
- ASLR – Address space layout randomization
- ATT&CK – Adversarial Tactics, Techniques, and Common Knowledge
- AV – Antivirus
- BEC – Business email compromise
- BYOD – Bring your own device
- C2 – Command and control