Free · Open Source · Updated for 2026
Get your CAC working at home.
Without the headache.
Clear, modern, step-by-step guides for using your DoD Common Access Card on your personal Windows, Mac, or Linux computer — written in plain English and kept current by the community.
Pick your operating system
Windows 10 & 11
Usually plug-and-play. Install the DoD certificates and you're most of the way there.
Windows guide →macOS
Native smart card support is built in. A few settings and certificates and you're done.
macOS guide →Linux & ChromeOS
OpenSC makes it work on nearly every distro — and ChromeOS has an app for that.
Linux guide →Everything you need — just three things
A card reader
Any modern USB smart card reader works. Most cost $10–20 and need no driver disc.
Choosing a reader →DoD certificates
Free from the DoD Cyber Exchange. They let your computer trust military websites.
Installing certificates →A few settings
Point your browser at your card, pick the right certificate, and sign in.
Browser setup →Common tasks
Digitally sign a PDF
Sign forms and memos with Adobe Acrobat Reader or other tools — no printer required.
Sign & encrypt email
Set up S/MIME in Outlook so you can send and read signed or encrypted messages.
Locked or forgotten PIN
What actually happens after three wrong tries — and how to get it reset.
Certificate not showing up
The most common sign-in failure, and the checklist that fixes it.
Reach NIPR from home (Air Force)
Set up EITaaS VDI — the virtual desktop that replaced Desktop Anywhere and AVD.
Use your CAC on a phone
Readers, apps, and Purebred — what actually works on iPhone and Android.