4 ms·

> TPMs are soldered onto motherboards so they are not portable. Like U2F, they also don’t let you sign arbitrary data. Incorrect! You can use TPM chips to RSA

> TPMs are soldered onto motherboards so they are not portable. Like U2F, they also don’t let you sign arbitrary data. Incorrect! You can use TPM chips to RSA sign arbitrary data, and use that to authenticate SSH: https://blog.habets.se/2013/11/How-TPM-protected-SSH-keys-work.html https://blog.habets.se/2013/11/How-TPM-protected-SSH-keys-wo... Even under Windows: https://blog.habets.se/2016/10/Windows-SSH-client-with-TPM.html https://blog.habets.se/2016/10/Windows-SSH-client-with-TPM.h... The secret is using TSS_HASH_OTHER as the hash algorithm, which tells the TPM "it's already hashed". Whether it actually is hashed, or just raw input, is up to you.

Rafert 6y ago
TPMs are also sold separately that which can be plugged in to motherboards, e.g. Gigabyte (https://www.gigabyte.com/us/Motherboard/GC-TPM20-SPI-20 https://www.gigabyte.com/us/Motherboard/GC-TPM20-SPI-20) and Asus (https://www.asus.com/Motherboards-Components/Motherboards/Accessories/TPM-M-R2-0/ https://www.asus.com/Motherboards-Components/Motherboards/Ac...) to name a couple. The article has a couple of other weird faults, too: 1. I'm not sure why the author is complaining about FIDO2 having backwards compatibility with U2F/CTAP1. The article even incorrectly claims FIDO2 is "a 3rd incompatible standard" only to counter-argue the point a few paragraphs below explaining CTAP? People not having to throw away their perfectly fine old devices is a good thing in my book. 2. "All FIDO standards are web-centric and aren’t designed with any other client software in mind" the first part is true, the second part not so much. For example FIDO2 supports silent authentication (no user interaction) while WebAuthn explicitly does not[0]. It also supports the hmac-secret extension[1] which is used for offline authentication with Azure Active Directory[2] and IIRC no WebAuthn browser implementation exposes this extension to web apps. [0]: see e.g. discussion on https://github.com/w3c/webauthn/issues/199 https://github.com/w3c/webauthn/issues/199 [1]: https://fidoalliance.org/specs/fido-v2.1-rd-20210309/#sctn-hmac-secret-extension https://fidoalliance.org/specs/fido-v2.1-rd-20210309/#sctn-h... [2]: https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-authentication-passwordless#fido2-security-keys https://docs.microsoft.com/en-us/azure/active-directory/auth...
lstamour 6y ago
Also on a modern Apple device, you can use the Secure Enclave AES Engine to perform encryption and decryption. You can also use the Public Key Accelerator (PKA) for RSA and ECC (Elliptic Curve Cryptography) signing and encryption algorithms with hardware keys that stay within the PKA. https://support.apple.com/en-ca/guide/security/sec59b0b31ff/web https://support.apple.com/en-ca/guide/security/sec59b0b31ff/... covers an overview of the technologies involved. Of particular interest is probably the "Secure Enclave feature summary" at the bottom of that page which lists which Apple chips support which features. Also relevant: https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/storing_keys_in_the_secure_enclave https://developer.apple.com/documentation/security/certifica... and CryptoKit https://developer.apple.com/news/?id=3bwfq45y https://developer.apple.com/news/?id=3bwfq45y and https://developer.apple.com/documentation/cryptokit https://developer.apple.com/documentation/cryptokit (Note that the Linux version of CryptoKit doesn't get any of the fancy hardware features, you'll need an Apple OS for them.)
Arnavion 6y ago
I also don't know why the author thinks HSMs cost "hundreds to tens of thousands of dollars". In the first place, TPMs are a subcategory of HSMs and don't cost that much. In the second place, HSMs like the Microchip ATECC608B cost <$1 for the bare board.
- OJFord 6y ago
  OP says devices, so I read rack-mount gear that you buy when you can't use (or trust) AWS KMS, not chips.
  - noinsight 6y ago
    Even then, you can buy a Yubico YubiHSM device for 650€.
    - asalahli 6y ago
      Well, that is hundreds of dollars, isn't it? :)
  - gnufx 6y ago
    Not yet implemented, but Solo 2 has a "stretch goal" to provide HSM functionality, if that would be good enough. https://www.indiegogo.com/projects/solo-v2-safety-net-against-phishing#/updates/all https://www.indiegogo.com/projects/solo-v2-safety-net-agains...
  - Arnavion 6y ago
    Well, I don't know if they really meant rack-mount gear, but sure it costs a little extra to get it usable with a general-purpose computer. Specifically, you can get that Microchip HSM in a form factor that plugs into a click shield, then plug the click shield into a Raspberry Pi's GPIO pins. You now have a PKCS#11-usable HSM from a Pi. Including the click shield still puts the cost at <$20. (I have a few such setups lying around because my $dayjob includes a PKCS#11-consuming application that runs on such setups.)
  - EvanAnderson 6y ago

Rafert 6y ago

TPMs are also sold separately that which can be plugged in to motherboards, e.g. Gigabyte (https://www.gigabyte.com/us/Motherboard/GC-TPM20-SPI-20 https://www.gigabyte.com/us/Motherboard/GC-TPM20-SPI-20) and Asus (https://www.asus.com/Motherboards-Components/Motherboards/Accessories/TPM-M-R2-0/ https://www.asus.com/Motherboards-Components/Motherboards/Ac...) to name a couple. The article has a couple of other weird faults, too: 1. I'm not sure why the author is complaining about FIDO2 having backwards compatibility with U2F/CTAP1. The article even incorrectly claims FIDO2 is "a 3rd incompatible standard" only to counter-argue the point a few paragraphs below explaining CTAP? People not having to throw away their perfectly fine old devices is a good thing in my book. 2. "All FIDO standards are web-centric and aren’t designed with any other client software in mind" the first part is true, the second part not so much. For example FIDO2 supports silent authentication (no user interaction) while WebAuthn explicitly does not[0]. It also supports the hmac-secret extension[1] which is used for offline authentication with Azure Active Directory[2] and IIRC no WebAuthn browser implementation exposes this extension to web apps. [0]: see e.g. discussion on https://github.com/w3c/webauthn/issues/199 https://github.com/w3c/webauthn/issues/199 [1]: https://fidoalliance.org/specs/fido-v2.1-rd-20210309/#sctn-hmac-secret-extension https://fidoalliance.org/specs/fido-v2.1-rd-20210309/#sctn-h... [2]: https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-authentication-passwordless#fido2-security-keys https://docs.microsoft.com/en-us/azure/active-directory/auth...

lstamour 6y ago

Also on a modern Apple device, you can use the Secure Enclave AES Engine to perform encryption and decryption. You can also use the Public Key Accelerator (PKA) for RSA and ECC (Elliptic Curve Cryptography) signing and encryption algorithms with hardware keys that stay within the PKA. https://support.apple.com/en-ca/guide/security/sec59b0b31ff/web https://support.apple.com/en-ca/guide/security/sec59b0b31ff/... covers an overview of the technologies involved. Of particular interest is probably the "Secure Enclave feature summary" at the bottom of that page which lists which Apple chips support which features. Also relevant: https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/storing_keys_in_the_secure_enclave https://developer.apple.com/documentation/security/certifica... and CryptoKit https://developer.apple.com/news/?id=3bwfq45y https://developer.apple.com/news/?id=3bwfq45y and https://developer.apple.com/documentation/cryptokit https://developer.apple.com/documentation/cryptokit (Note that the Linux version of CryptoKit doesn't get any of the fancy hardware features, you'll need an Apple OS for them.)

Arnavion 6y ago

I also don't know why the author thinks HSMs cost "hundreds to tens of thousands of dollars". In the first place, TPMs are a subcategory of HSMs and don't cost that much. In the second place, HSMs like the Microchip ATECC608B cost <$1 for the bare board.

OJFord 6y ago
OP says devices, so I read rack-mount gear that you buy when you can't use (or trust) AWS KMS, not chips.
- noinsight 6y ago
  Even then, you can buy a Yubico YubiHSM device for 650€.
  - asalahli 6y ago
    Well, that is hundreds of dollars, isn't it? :)
- gnufx 6y ago
  Not yet implemented, but Solo 2 has a "stretch goal" to provide HSM functionality, if that would be good enough. https://www.indiegogo.com/projects/solo-v2-safety-net-against-phishing#/updates/all https://www.indiegogo.com/projects/solo-v2-safety-net-agains...
- Arnavion 6y ago
  Well, I don't know if they really meant rack-mount gear, but sure it costs a little extra to get it usable with a general-purpose computer. Specifically, you can get that Microchip HSM in a form factor that plugs into a click shield, then plug the click shield into a Raspberry Pi's GPIO pins. You now have a PKCS#11-usable HSM from a Pi. Including the click shield still puts the cost at <$20. (I have a few such setups lying around because my $dayjob includes a PKCS#11-consuming application that runs on such setups.)
- EvanAnderson 6y ago