Tangent — a question you didn't ask, but I'll pretend you did:

> If employers allowed employees to "bring their own devices", and then didn't force said employees to run MDM software on those devices, then how in the world could the employer guarantee the integrity of any line-of-business software the employee must run on the device; impose controls to stop PII + customer-shared data + trade secrets from being leaked outside the domain; and so forth?

My answer to that question: it's safe to say that most people in the modern day are fine with the compromise that your device might be 100% yours most of the time; but, when necessary — when you decide it to be so — 99% yours, 1% someone else's.

For example, anti-cheat software in online games.

The anti-cheat logic in online games, is this little nugget of code that runs on a little sub-computer within your computer (Intel SGX or equivalent.) This sub-computer acts as a "black box" — it's something the root user of the PC can't introspect or tamper with. However:

• Whenever you're not playing a game, the anti-cheat software isn't loaded. So most of the time, your computer is entirely yours.

• You get to decide when to play an online game, and you are explicitly aware of doing so.

• When you are playing an online game, most of your computer — the CPU's "application cores", and 99% of the RAM — is still 100% under your control. The anti-cheat software isn't actually a rootkit (despite what some people say); it can't affect any app that doesn't explicitly hook into it.

• In a brute-force sense, you still "control" the little sub-computer as well — in that you can force it to stop running whatever it's running whenever you want. SGX and the like aren't like Intel's Management Engine (which really could be used by a state actor to plant a non-removable "ring -3" rootkit on your PC); instead, SGX is more like a TPM, or an FPGA: it's something that's ultimately controlled by the CPU from ring 0, just with a very circumscribed API that doesn't give the CPU the ability to "get in the way" of a workload once the CPU has deployed that workload to it, other than by shutting that workload off.

As much as people like Richard Stallman might freak out at the above design, it really isn't the same thing as your employer having root on your wheelchair. It's more like how someone in a wheelchair knows that if they get on a plane, then they're not allowed to wheel their own wheelchair around on the plane, and a flight attendant will instead be doing that for them.

How does that translate to employer MDM software?

Well, there's no clear translation currently, because we're currently in a paradigm that favors employer-issued devices.

But here's what we could do:

• Modern PCs are powerful enough that anything a corporation wants you to do, can be done in a corporation-issued VM that runs on the computer.

• The employer could then require the installation of an integrity-verification extension (essentially "anti-cheat for VMs") that ensures that the VM itself, and the hypervisor software that runs it, and the host kernel the hypervisor is running on top of, all haven't been tampered with. (If any of them were, then the extension wouldn't be able to sign a remote-attestation packet, and the employer's server in turn wouldn't return a decryption key for the VM, so the VM wouldn't start.)

• The employer could feel free to MDM the VM guest kernel — but they likely wouldn't need to, as they could instead just lock it down in much-more-severe ways (the sorts of approaches you use to lock down a server! or a kiosk computer!) that would make a general-purpose PC next-to-useless, but which would be fine in the context of a VM running only line-of-business software. (Remember, all your general-purpose "personal computer" software would be running outside the VM. Web browsing? Outside the VM. The VM is just for interacting with Intranet apps, reading secure email, etc.)

(Why yes, I am describing https://en.wikipedia.org/wiki/Multilevel_security.)