U2F and nRF52840

[NIIBE Yutaka]

Jeremy Drake <jeremydrake+gnuk at eacceleration.com> wrote:
> Is it?  I haven't looked too closely, but I was under the impression that 
> U2F was implemented as a HID device rather than CCID/"smartcard".

Right.  I was wrong.  U2F defines three protocols (for Bluetooth, NFC
and USB), and USB one is HID.

Well, in Gnuk, there is an experimental implementation for HID protocol.

The HID implementation in Gnuk is not general one, but very specific
use.  It was old experiment.  I was considering using it to control
(virtual) card of Gnuk, so that Gnuk can support multiple cards and a
user can send command of "insert" / "remove" of card.
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