Are there USB-C to, uh, "normal" USB adapters out? You know, that go the OTHER way?

I'd hate to not be able to use the USB-C Yubikey with my desktop, my keyboard port, my hubs, etc. Seems easier to just use the normal Yubikey plus a dongle for the few machines that support USB-C.

Unfortunately the standard explicitly forbids that type of adapter because they could be used to plug two USB-A power supplies together. (USB-C power supplies are designed to prevent this from being an issue.) Source: https://plus.google.com/+BensonLeung/posts/UFCHbSDRa2o

That doesn't mean they don't exist - you can find a few on Amazon - but reputable companies aren't making them, so quality is going to be suspect.

I think the term you're after for "normal" might be USB Type-A :)

I really, Really, REALLY love my nano and can't wait for a USB-C version. Actually, that is one of the things that would make me not want a new MBP.

I like the form factor, but as a second factor it sucks. Effectively your computer becomes the second factor, and it's much more likely that your laptop (with the Nano plugged in it) is stolen, than a keychain with a bigger Neo.

It's acceptable if you only use it for OTP, but I can't get myself to put GPG private keys on a Yubikey Nano...

The Nano is essentially a Client Certificate in USB form.

You could just put a GPG subkey on it. That way it's revokable if lost, without destroying your entire PGP key.

Why? Your GPG key is airgapped and inextricable (except possibly via something like a DPA-style attack), and you can set a PIN required to perform any private key operations, complete with a configurable number of attempts before the device wipes itself.

There are DPA attacks to be worried about, but if you set a decent PIN and limit the number of failed attempts your GPG keys will probably be safe if your Yubikey is ever lost/stolen.

That is not what airgapped means.

I figure I can get a lot more security with a practical-length passphrase than a practical-length PIN.

I have a 6 digit pin (8 digit admin pin) with 3 retries before the device wipes itself. The chances of an attacker cracking that are negligible - I'm more concerned about someone observing my typing (applies to passphrase as well) or actual physical attacks on the yubikey (stolen, decapped, ...) but I'm not the target demographic where such effort would be warranted (or at least I hope so). An attacker could backdoor my PC and intercept the passphrase dialog - but in that case he'd still need my yubikey which makes remote attacks impractical and makes me notice the theft. This is not the case with a passphrase on a secret key - a machine compromise may silently take everything without you ever noticing.