Auto-Submit U2F login

Description

When using U2F for 2FA login the user already has to show presence at the device (tapping, inserting the U2F token). Thus explicit request of using U2F and confirming of having done so is kinda redundant. If U2F devices are registered with an account they should be expected to be used for 2FA logins - with the possibility to restart in cases of a timeout. In the best case this reduces the 2FA step to simply tapping or inserting the token - omitting the currently necessary additional two button clicks.

Proposal

Automatically wait for U2F tokens when a login requires 2FA confirmation and the user has U2F tokens registered in her account. Upon successful use of the U2F token for login, automatically submit the form, giving a behaviour similar to that of Github.

Links / references

https://help.github.com/articles/providing-your-2fa-authentication-code/