iOSでYubikey+SSHできるアプリあるんだ、と思ったけどYKCS11じゃないのか。PAMいじるのはヤダなぁ。
https://apple.stackexchange.com/questions/454258/ios-apps-that-lets-you-ssh-into-a-server-using-yubikey-5-nfc-with-public-key-aut/454410#454410
https://support.termius.com/hc/en-us/articles/4402453018393-YubiKey-support
Experimental private instance. Running on FreeBSD!