SDSI
| Acronym | Definition |
|---|---|
| SDSI | Simple Distributed Security Infrastructure |
| SDSI | Synergetic Data Systems, Inc. (est. 1988; Latrobe, CA) |
| SDSI | Systems Design & Support, Inc. |
| SDSI | Somos Diferentes, Somos Iguales (Spanish: We're Different, We're Equal) |
| SDSI | Secure Data Solutions, Inc (The Woodlands, TX) |
| SDSI | Space and Defense Systems Inc. (Reston, VA) |