| NSA | National Security Agency Fort Meade, http://www.nsa.gov |
| NSC | National Security Council Washington, DC, http://www.whitehouse.gov/nsc |
| NCSC | National Computer Security Center |
| NCSA | National Computer Security Association |
| NCSC | National Computer/Computing Security Center |
| NASDAQ | National Association of Security Dealers Automated Quotations ein automatisches Kursnotierungssystem für Wertpapiere |
| CISE | Computer and Information Science and Engineering directorate |
| ES | Enhanced Security |
| SM | Security Management |
| SAS | Security Association |
| COMSEC | Communications Security |
| RSI | Repent Security, Inc. |
| RHSA | Red Hat Security Advisory |
| DSA | Debian Security Advisory |
| SAD | Security Association Database |
| ISSI | Information Security Systems Inc. |
| CSS | Central Security Service Abteilung des US-Amerikanischen Geheimdiensts NSA |
| CSI | Computer Security Institute San Francisco, USA |
| CSEA | Cyber Security Enhancement Act |
| CSA | Cyber Security Agency, EU |
| SCA | Security Control and Audit |
| SDB | Security Policy Database |
| SEC | Security Exchange Commission |
| EROS | Enhanced Return Of Security |
| NSC | Network Security Controller |
| NSO | Network Security Officer |
| NSS | Network Security Scanner |
| MSP | Message Security Protocol |
| MLS | Multi Level Security |
| LSM | Linux Security Module |
| LSA | Local Security Authority |
| OPSEC | Open Platform for Security |
| ISS | Integrated Security Systems Irving, [TX], http://www.integratedsecurity.com |
| ISS | Internet Security Systems Kassel, http://www.iss.net/emea/germany |
| PSE | Personal Security Environment |
| GSA | Global Security Architecture |
| RSN | Russian Security Newsline |
| ESM | Enterprise Security Manager |
| GSS | Generic Security Service |
| CLSR | Computer Law & Security Report |
| TSA | Transportation Security Administration |
| SID | Security Identification / Identifier |
| TLS | Transport Layer Security |
| SLS | Shared Level Security |
| VSC | Voice Security Card |
| SEL | Security Enhanced Linux |
| SSO | System Security Officer |
| SPI | Security Parameter Index |
| SRP | Security Rollup Package |
| ESP | Encapsulated/Encapsulating Security Payload |