Add support for Solo V2 NFC on iPhone/iPad

[Timtam]

Solokeys just started shipping their Solo V2 devices which come with either USB A or USB-C and NFC support. Its not the first NFC device of their brand, but its probably going to be the most common one soon.
I tried using it with Strongbox for the first time today (never used a different NFC key before). I changed the master access credentials, entered my password and selected NFC slot 1. It asked me to scan my device, which I did, but directly after finding it and approving it via a vibration and noise, I got the following message from Strongbox:

Unable to serialize to kdbx (stage 1).

I think this might have something to do with the fact that the Solo V2 requires approval by tapping the buttons on the side of the device (at least thats how it works in USB mode and I'd expect it to work the same way in NFC mode too) and it doesn't seem like Strongbox gives me the time to actually do so, because it reacts as soon as the device gets scanned.

Is there anything you can do to support Solo too?

The key is not yet free to buy everywhere, its on Indigogo right now, but i'd expect it to be publically available in the next few months as well.
https://www.indiegogo.com/projects/solo-v2-safety-net-against-phishing#/

Please let me know if I can do something to help you debug the issue, as i'd really like to see the device supported by Strongbox as well.

[strongbox-mark]

Hi there, thanks for the request. That looks interesting. Are you in touch with the developers, or could you ask them to get in touch with me?

I'd need to know if it supports HMACSHA1 challenge response and what kind of SDK/Library support is offered/available.

I'd also need a physical device to test the integration. If you can help with any of that, I'd be happy to try integrate this, :)

[Timtam]

Thanks for getting back to me. I'm not yet in touch with the developers, but i'll see if I can arrange something ASAP. For the meantime, the firmware is all open-sourced and can be found on GitHub as well, written in rust:

https://github.com/solokeys/solo2

If you're interested, you could probably check the repo out to see if that helps you any further.
I don't have two devices right now unfortunately, so i'll ask the developers about a sample for you so that you can add support for it. If they aren't willing to offer one, i'll see that I purchase a second one for you to get your hands on.

[strongbox-mark]

Sounds great, and very kind of you.

Let's make sure they support HMACSHA1 CR and that we can integrate easily before any purchases though :) I'm sure they'll be able to chime in here and let us know.

[shortyxs]

I am interested in this feature as well, because I prefere the open source approach of Solokeys over a YubiKey.
So I am interested, if there is any progress?
Maybe a schedule? Before I buy one of these.

[svn2208]

Might this help?
https://github.com/MartinKolarik/KeePassFIDO2
Or this?
keepassxreboot/keepassxc#3560
Also:
solokeys/solo1#348

A comment regarding HMACSHA1 by the creators:
solokeys/kickstarter2021#23 (comment)