krypton-ios VS OpenSK

I used this when it was still Krypton [0], it worked very well, it just gives you a "Want to log in?" notification on your phone, but for almost anything imaginable (inc SSH). I don't see it used much though.

[0] https://krypt.co/

Using your SIM card for MFA when logging in to an SSH server (through paid API requests to a third party)

There are ways to use your phone's secure storage capabilities for key storage. I've dabbled with using Krypt.co [1] for this, though that's sadly been deprecated and will at some point be replaced by a paid-for cloud service from Akamai. I'm sure there are other options available as well.

A far superior method for SSH security would be a physical U2F key or even a smart card. It's also possible to set up TOTP as a second factor ([2], works with any TOTP solution, not just Google Authenticator). I don't see a need for this paid-for third party service unless you're already using their services for some kind of verification mechanism.

[1]: https://krypt.co/

[2]: https://github.com/google/google-authenticator-libpam

Krypton (https://krypt.co), now owned by Akamai (https://akamai.com/mfa) who removed one of the best features, IMO (SSH key on a phone...) does this to an extent... Akamai says it's FIDO2... have not used it in a while... It is free though until Akamai decides not to give it away...

Here's the announcement on the website of the FIDO alliance: https://fidoalliance.org/apple-google-and-microsoft-commit-t...

I hope this cross device system will be cross platform, but I wouldn't be surprised if you could only choose between macOS/iOS, Chrome/Chrome, or Edge/Edge sync.

Funnily enough, a system for signing web authentication requests from a mobile device is far from new: I've been using https://krypt.co/ for years (though it's on the long road of sunsetting right now) and I hope that will last long enough for the new cross device standard to replace it.

> For the purpose of login in with a private key, i would prefer some browser extension (or built in the browser) that generates a key from a seed (like a crypto wallet) and only does that. This doesn't exist at this point.

What about https://www.yubico.com/products/yubikey-5-overview/ or https://cloud.google.com/titan-security-key/ or https://krypt.co/ (before it was acquired, I still use it though) or any of it's equivalents?

NOTE: Sometimes, if you are using a key-manager like Krypt.co you will not have the typical .pub file to copy, in which case using ssh-copy-id -f option will force it to copy anything close to a public key and this works for me.

Krypton is a great little multi-factor authentication tool that stores your SSH and U2F keys on your phone and provides an SSH agent and a browser extension that send approval requests to your phone when those keys are invoked. Ie., you ssh into your server and a notification pops up on your phone asking you if it's okay. It also handily GPG-signs your Git commits.

Here's the URL, since finding it via search is hard: https://krypt.co/

check this https://krypt.co/

Trusting your HSM vendor is a requirement if you don't want your keys to be exportable, and there's much less risk in doing so compared to trusting Apple for other things like secure communications (iMessage is e2ee but doesn't tell you when your peer changes/adds keys and backups to iCloud by default).

Also, a lot of people who use Krypton don't know that SSH keys actually don't use the secure enclave because it doesn't support rsa or ed25519: https://github.com/kryptco/krypton-ios/issues/73#issuecommen...

https://github.com/google/OpenSK works, it runs on something like this $15 board. Could do with a case though.

https://www.nordicsemi.com/About-us/BuyOnline?search_token=n...

There are a huge number of other vendors supporting Webauthn apart from Yubikey. (From the top of my head Nitrokey, Solo, Tomu, Mooltipass, Ledger, Trezor, Google Titan, OnlyKey, Token2).

You could also use the system TPM (https://github.com/psanford/tpm-fido).

A brief search didn't yield any FIDO2 software-only solutions for Linux, but I see no reason why in principle you couldn't implement it (perhaps interfacing https://github.com/google/OpenSK through hidg - similar projects do exist for U2F).

Cloudflare does, using a security key not found in the FIDO Metadata Service will unfortunately not work. This precludes the use of any hacker-friendly solution (making your own).

> Supported: All security keys found in the FIDO Metadata Service 3.0, unless they have been revoked for security reasons.

https://support.cloudflare.com/hc/en-us/articles/44068890480...

Attestation keys, as they're currently used, aren't very "privacy friendly" and it's much worse for those who wish to create their own key.

> Usually, the attestation private key is shared between a batch of at least 100,000 security keys of the same model. If you build your own OpenSK, your private key is unique to you. This makes you identifiable across registrations: Two websites could collaborate to track if registrations were attested with the same key material. If you use OpenSK beyond experimentation, please consider carefully if you want to take this privacy risk.

https://github.com/google/OpenSK/blob/f2496a8e6d71a4e8388849...

There are a number of FOSS solutions.

- https://github.com/google/OpenSK <- DIY solution

- https://solokeys.com/

- https://www.nitrokey.com/

The issue with any FOSS solution is that FIDO requires an attestation private key which is shared between a batch of at least 100,000 security keys. Using a DIY or cli app (application running on the host) solution will likely mean you'll be generating that private key yourself, this makes you identifiable across registrations.

I'm not sure what you're replying to--this scheme is much closer to self-signed X509 client certs, not FIDO. But regarding FIDO, it does not prevent user-controlled hardware; it's up to RPs to choose if they require specific device manufacturers or not.

In my experience, the vast majority of (consumer) RPs do not require specific batch attestation, which is why you can make your own FIDO key: https://github.com/google/OpenSK.

I am under the impression support for attestation was controversial in FIDO--it's clearly useful for enterprise scenarios (e.g. where an enterprise requires some silly certification like FIPS: https://support.yubico.com/hc/en-us/articles/360016614760-Ac...), but there's always the risk that consumer-facing RPs require it for no good reason.

My employer requires FIPS certification due to FedRAMP; I'd be interested in how you would propose to change FIDO such that--as now--I can use a single key for work and for all my consumer needs while eliminating attestation.