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If any FIDO experts are reading this, two technical questions: 1. Is there anything in the standard about proving to the server that you have a genuine FIDO de

If any FIDO experts are reading this, two technical questions: 1. Is there anything in the standard about proving to the server that you have a genuine FIDO device that meets certain standards, and not say a piece of software that is merely pretending to be a hardware security module? If so, I presume the Solo will come with whatever certification / digital signature is required? 2. My understanding of FIDO (v1) is that the only function a device has to offer is authentication through digital signature, so a FIDO v1 device is no use as an extra authentication factor to unlock a password manager without "cloud" support (such as pwsafe) as it doesn't provide you with anything that a hacker couldn't work around - as opposed to a token that stores a cryptographic key and releases it when you press the button (which you can set up a yubikey to do). Is this correct, and does FIDO2 change this situation?

bsder 8y ago
From looking at the design docs, Solo doesn't use the ARM TrustZone, yet, so it can't validate firmware.
agl 8y ago
> Is there anything in the standard about proving to the server that you have a genuine FIDO device Yes. When registering a credential you can request[1] attestation information. Generally this will come in the form of an X.509 certificate[2] per batch of 100,000 devices which is signed by the manufacturer and which signs the generated key. FIDO is planning on running a central registry[3] of devices which should include their certifications and manufacturer public keys etc. For more details, see [4]. > My understanding of FIDO (v1) is that the only function a device has to offer is authentication through digital signature. That's correct: CTAP1 just signs things. You can prove to a remote service that the credential is in live use right now because it signs over a server-provided nonce to show freshness, but that's all. With CTAP2, devices can store keys themselves and they can provide a random oracle (i.e. HMAC) for unlocking locally encrypted data[5]. FIDO2 devices can also require a PIN to be provided before keys are released. (Or have a local fingerprint reader, although I don't know of any such devices yet.) [1] https://www.w3.org/TR/webauthn/#attestation-convey https://www.w3.org/TR/webauthn/#attestation-convey [2] https://www.w3.org/TR/webauthn/#fido-u2f-attestation https://www.w3.org/TR/webauthn/#fido-u2f-attestation [3] https://fidoalliance.org/mds/ https://fidoalliance.org/mds/ [4] https://www.imperialviolet.org/2018/03/27/webauthn.html#attestation https://www.imperialviolet.org/2018/03/27/webauthn.html#atte... [5] https://fidoalliance.org/specs/fido-v2.0-rd-20180702/fido-client-to-authenticator-protocol-v2.0-rd-20180702.html#sctn-hmac-secret-extension https://fidoalliance.org/specs/fido-v2.0-rd-20180702/fido-cl...
- red_admiral 8y ago
  First of all, thank you for the high quality response! A FIDO2 device with fingerprint reader was supposedly launched at RSA 2018 [1][2]. [1] https://mobileidworld.com/fido2-compliant-usb-key-fingerprint-904133/ https://mobileidworld.com/fido2-compliant-usb-key-fingerprin... [2] https://www.slideshare.net/FIDOAlliance/fido-kwg-tech-seminar-16-jul-2018-ewbm https://www.slideshare.net/FIDOAlliance/fido-kwg-tech-semina...
  - ecesena 8y ago
    I think it's this one: http://www.e-wbm.com/fido_usb.jsp http://www.e-wbm.com/fido_usb.jsp But I couldn't find where to buy it.
ecesena 8y ago
1. Yes, it's called attestation, and you can read more here [1]. For example recently Amazon launched support for U2F only allowing some yubikeys. 1b. Solo will have its own attestation certificate, so you'd be able to say I wan't/don't want to accept Solo. I believe this will be more valuable to enterprise/closed environments that publicly available services, but of course an option. 2. FIDO2 and "1" (U2F) work pretty much the same. The device signs a challenge together with the hostname of the website you're visiting. There's no release of any key material. Yubikes, other than FIDO2/U2F, support other protocols including OpenPGP or SSH, but this is kind of a different story. Makes sense? [1] https://fidoalliance.org/fido-technotes-the-truth-about-attestation/ https://fidoalliance.org/fido-technotes-the-truth-about-atte...
- red_admiral 8y ago
  Makes sense, thanks - and congratulations on how the kickstarter is going so far! Is Solo going to support the HMAC extension that @agl talked about below?

bsder 8y ago

From looking at the design docs, Solo doesn't use the ARM TrustZone, yet, so it can't validate firmware.

agl 8y ago

> Is there anything in the standard about proving to the server that you have a genuine FIDO device Yes. When registering a credential you can request[1] attestation information. Generally this will come in the form of an X.509 certificate[2] per batch of 100,000 devices which is signed by the manufacturer and which signs the generated key. FIDO is planning on running a central registry[3] of devices which should include their certifications and manufacturer public keys etc. For more details, see [4]. > My understanding of FIDO (v1) is that the only function a device has to offer is authentication through digital signature. That's correct: CTAP1 just signs things. You can prove to a remote service that the credential is in live use right now because it signs over a server-provided nonce to show freshness, but that's all. With CTAP2, devices can store keys themselves and they can provide a random oracle (i.e. HMAC) for unlocking locally encrypted data[5]. FIDO2 devices can also require a PIN to be provided before keys are released. (Or have a local fingerprint reader, although I don't know of any such devices yet.) [1] https://www.w3.org/TR/webauthn/#attestation-convey https://www.w3.org/TR/webauthn/#attestation-convey [2] https://www.w3.org/TR/webauthn/#fido-u2f-attestation https://www.w3.org/TR/webauthn/#fido-u2f-attestation [3] https://fidoalliance.org/mds/ https://fidoalliance.org/mds/ [4] https://www.imperialviolet.org/2018/03/27/webauthn.html#attestation https://www.imperialviolet.org/2018/03/27/webauthn.html#atte... [5] https://fidoalliance.org/specs/fido-v2.0-rd-20180702/fido-client-to-authenticator-protocol-v2.0-rd-20180702.html#sctn-hmac-secret-extension https://fidoalliance.org/specs/fido-v2.0-rd-20180702/fido-cl...

red_admiral 8y ago
First of all, thank you for the high quality response! A FIDO2 device with fingerprint reader was supposedly launched at RSA 2018 [1][2]. [1] https://mobileidworld.com/fido2-compliant-usb-key-fingerprint-904133/ https://mobileidworld.com/fido2-compliant-usb-key-fingerprin... [2] https://www.slideshare.net/FIDOAlliance/fido-kwg-tech-seminar-16-jul-2018-ewbm https://www.slideshare.net/FIDOAlliance/fido-kwg-tech-semina...
- ecesena 8y ago
  I think it's this one: http://www.e-wbm.com/fido_usb.jsp http://www.e-wbm.com/fido_usb.jsp But I couldn't find where to buy it.

ecesena 8y ago

1. Yes, it's called attestation, and you can read more here [1]. For example recently Amazon launched support for U2F only allowing some yubikeys. 1b. Solo will have its own attestation certificate, so you'd be able to say I wan't/don't want to accept Solo. I believe this will be more valuable to enterprise/closed environments that publicly available services, but of course an option. 2. FIDO2 and "1" (U2F) work pretty much the same. The device signs a challenge together with the hostname of the website you're visiting. There's no release of any key material. Yubikes, other than FIDO2/U2F, support other protocols including OpenPGP or SSH, but this is kind of a different story. Makes sense? [1] https://fidoalliance.org/fido-technotes-the-truth-about-attestation/ https://fidoalliance.org/fido-technotes-the-truth-about-atte...

red_admiral 8y ago
Makes sense, thanks - and congratulations on how the kickstarter is going so far! Is Solo going to support the HMAC extension that @agl talked about below?