The ATAP group within Google is doing really neat (and secure) things with external storage devices.
We're at Google's ATAP (the Advanced Technology And Projects group, and self-proclaimed pirates that "make epic shit") session during Google I/O 2015, and we just saw our first look at Project Vault — one of those crazy projects that folks at Google love to get started.
Project Vault is a hardware and software isolated environment in the form of a micro SD card … Project vault will enable secure communications and storage
It's not just an SD card. In actuality, there's a microprocessor inside and an NFC chip, as well as things like a dedicated random number generator. Just the sort of things a crypto-engine-on-a-stick would need. The host thinks the microcomputer is just regular storage, and nothing need done to use it — there are no drivers needed, and it works on any operating system. Once in place, you simply use the Project Vault storage like any other SD card. Things stay secure no matter where or how you're using it.
Google is releasing the bits and pieces developers need to further the project, but there is no consumer release in the near future. The demo looked really cool, and we're glad that people this smart care about our security and privacy.