Using a US DOD CAC on Android The US Department of Defence (DOD) uses a Common Access Card (CAC) for authentication on a number of externally available websites. It is possible to use the CAC with Firefox on Linux (e.g., see the Arch Linux wiki). From my understanding, the CAC is a fairly standard smartcard. 

Are there smartcard/CAC readers and web browsers that are compatible with Android? If not, are there technical limitations that prevent it?
Arg, the military and their acronyms. Anyway yes there are some companies that are TAA compliant (Trade Agreements Act [19 U.S.C. &amp; 2501-2581]) 

Thursby with PKard is one that is known to have a working model for both CAC or PIV (Personal Identity Verification) cards.
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Samsung Knox also has a working system and they do have DOD contracts. I believe they are TAA compliant because they are from a friendly foreign country. At what clearance level though I am unsure about because of the foreign country thing. Reference