Features:
+* cryptenroll/cryptsetup/homed: add unlock mechanism that combines tpm2 and
+ fido2, as well as tpm2 + ssh-agent, insipred by ChromeOS' logic: encrypt the
+ volume key with the TPM, with a policy that insists that a nonce is signed by
+ the fido2 device's key or ssh-agent key. Thus, add unlock/login time the TPM
+ generates a nonce, which is sent as a challenge to the fido2/ssh-agent, which
+ returns a signature which is handed to the tpm, which then reveals the volume
+ key to the PC.
+
+* cryptenroll/cryptsetup/homed: similar to this, implement TOTP backed by TPM.
+
* expose the handoff timestamp fully via the D-Bus properties that contain
ExecStatus information