Security+ Acronyms
CompTIA publishes an acronym list with the SY0-701 objectives and then writes questions that use the short form without expanding it. These are grouped by subject rather than alphabetically, because that is how they come up.
Security+ Acronyms · firsttry.app/cheatsheets/security-plus-acronyms · original reference written from published exam objectives. Not affiliated with any certification body.
Identity and access
| Acronym | Expansion | What it is |
|---|---|---|
| AAA | Authentication, Authorization, Accounting | The three things an access system does |
| MFA | Multifactor Authentication | Two or more different factor types |
| SSO | Single Sign-On | One login across many services |
| SAML | Security Assertion Markup Language | XML federation, common in enterprise SSO |
| OIDC | OpenID Connect | Identity layer on top of OAuth 2.0 |
| LDAP | Lightweight Directory Access Protocol | Directory queries, port 389 |
| RBAC | Role-Based Access Control | Permissions attached to a role |
| ABAC | Attribute-Based Access Control | Permissions from attributes and context |
| PAM | Privileged Access Management | Controls over admin accounts |
| JIT | Just In Time | Privilege granted only when needed |
| TOTP | Time-based One-Time Password | The rotating six-digit code |
| FIDO | Fast Identity Online | Hardware-backed passwordless standard |
Cryptography
| Acronym | Expansion | What it is |
|---|---|---|
| AES | Advanced Encryption Standard | Symmetric block cipher, 128 to 256 bit keys |
| RSA | Rivest Shamir Adleman | Asymmetric, key exchange and signatures |
| ECC | Elliptic Curve Cryptography | Asymmetric with smaller keys than RSA |
| PKI | Public Key Infrastructure | The whole certificate system |
| CA | Certificate Authority | Issues and signs certificates |
| CSR | Certificate Signing Request | What you send a CA to get a certificate |
| CRL | Certificate Revocation List | Published list of revoked certificates |
| OCSP | Online Certificate Status Protocol | Live revocation check, replaces polling a CRL |
| HSM | Hardware Security Module | Tamper-resistant key storage |
| TPM | Trusted Platform Module | Key storage soldered to the machine |
| PFS | Perfect Forward Secrecy | A stolen private key cannot decrypt past sessions |
| HMAC | Hash-based Message Authentication Code | Integrity plus authenticity, using a shared key |
Network defense and operations
| Acronym | Expansion | What it is |
|---|---|---|
| IDS / IPS | Intrusion Detection / Prevention System | Detection alerts, prevention blocks |
| WAF | Web Application Firewall | Layer 7 filtering in front of an application |
| NGFW | Next-Generation Firewall | Application awareness and inspection |
| SIEM | Security Information and Event Management | Log aggregation, correlation and alerting |
| SOAR | Security Orchestration, Automation and Response | Playbooks that act on SIEM output |
| EDR / XDR | Endpoint / Extended Detection and Response | Endpoint telemetry, extended across other sources |
| DLP | Data Loss Prevention | Stops regulated data leaving |
| CASB | Cloud Access Security Broker | Policy enforcement between users and cloud apps |
| SASE | Secure Access Service Edge | Network and security delivered as one cloud service |
| ZTNA | Zero Trust Network Access | Per-request access decisions, no implicit trust |
| NAC | Network Access Control | Posture check before a device joins |
| SD-WAN | Software-Defined Wide Area Network | Policy-driven WAN path selection |
Risk, governance and continuity
| Acronym | Expansion | What it is |
|---|---|---|
| BIA | Business Impact Analysis | What an outage costs, per system |
| RTO | Recovery Time Objective | How long you may be down |
| RPO | Recovery Point Objective | How much data you may lose |
| MTTR | Mean Time To Repair | Average time to restore service |
| MTBF | Mean Time Between Failures | Average uptime between faults |
| SLA | Service Level Agreement | Contractual performance commitment |
| MOU | Memorandum of Understanding | Non-binding statement of intent |
| SLE / ALE | Single Loss / Annual Loss Expectancy | Cost of one event, and per year |
| ARO | Annual Rate of Occurrence | Expected events per year |
| SoD | Separation of Duties | No one person completes a sensitive task |
| SBOM | Software Bill of Materials | What is inside a piece of software |
| CVE / CVSS | Common Vulnerabilities and Exposures / Scoring System | The identifier, and its severity score |
Try it here
Three verified practice questions on this material. Answer one, and see the official page behind the answer.
4-1Security Operations
What is the minimum amount of entropy a session identifier should contain to resist brute-force guessing attacks?
2-2Vulnerability Management
A Greenbone report shows a finding with severity score 8.8. Which severity class does the report assign it?
Describe capabilities of Microsoft Entra
A help desk spends much of each Monday unlocking accounts and resetting forgotten passwords. Which Microsoft Entra feature lets users fix this themselves?
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