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What's wrong with client certificates? Instead of reinventing the wheel they should've just used those which would've given browser vendors a reason to improve

What's wrong with client certificates? Instead of reinventing the wheel they should've just used those which would've given browser vendors a reason to improve their UX regarding client certs.

ptoomey3 9y ago
That is roughly all U2F is. It is a per-origin key pair that is registered with each site and used to sign challenges. At some point browsers themselves might implement something like Soft U2F, at which point, they basically will have "improved the UX of client certs".
- Rjevski 9y ago
  The advantage of client certs over U2F is that client certs use the same proven mechanism your browser uses to verify the server's cert, and can even be handled by the web server. It's also seamless for the user - if needed you can be logged in right from the first request. U2F needs to be implemented over the top in the app itself and the login process is at the minimum two steps (no way to login from the first request).
wmf 9y ago
Most sites can't sacrifice all their users in the short term for the good of the Internet long-term.
Freak_NL 9y ago
With hardware U2F the benefit lies in not having the private key available on the client device at all. That means that copying it is impossible (without dismantling the key and using quite advanced equipment to attempt to read the private key). With software U2F I think you are right; client-side certs just work, now, in all major browsers. Installing them is a hassle, but it can be managed with good documentation (we use client-side certificates for authentication at the moment). Personally, I don't think software U2F should exist outside of development and testing scenarios.
- hdhzy 9y ago
  Well you can have client certificate on hardware. Some hardware even has attestation built in [0] so you can be sure that the private key is non exportable. PIV based smartcards do not require external drivers on most modern OSes. [0]: https://developers.yubico.com/PIV/Introduction/PIV_attestation.html https://developers.yubico.com/PIV/Introduction/PIV_attestati... U2F is designed for only one algorithm and allows a lot of optimizations (e.g the private keys are not really stored on the device but rather generated from master seed and origin). That's why they are substantially cheaper than PIV devices.
hdhzy 9y ago
Client certificates are best from security perspective but lack UX (this could be fixed) and are not designed with privacy in mind. U2F on the other hand generates unique pair of keys for each origin. By default.

What's wrong with client certificates? Instead of reinventing the wheel they should've just used those which would've given browser vendors a reason to improve their UX regarding client certs.

ptoomey3 9y ago

That is roughly all U2F is. It is a per-origin key pair that is registered with each site and used to sign challenges. At some point browsers themselves might implement something like Soft U2F, at which point, they basically will have "improved the UX of client certs".

Rjevski 9y ago
The advantage of client certs over U2F is that client certs use the same proven mechanism your browser uses to verify the server's cert, and can even be handled by the web server. It's also seamless for the user - if needed you can be logged in right from the first request. U2F needs to be implemented over the top in the app itself and the login process is at the minimum two steps (no way to login from the first request).

wmf 9y ago

Most sites can't sacrifice all their users in the short term for the good of the Internet long-term.

Freak_NL 9y ago

With hardware U2F the benefit lies in not having the private key available on the client device at all. That means that copying it is impossible (without dismantling the key and using quite advanced equipment to attempt to read the private key). With software U2F I think you are right; client-side certs just work, now, in all major browsers. Installing them is a hassle, but it can be managed with good documentation (we use client-side certificates for authentication at the moment). Personally, I don't think software U2F should exist outside of development and testing scenarios.

hdhzy 9y ago
Well you can have client certificate on hardware. Some hardware even has attestation built in [0] so you can be sure that the private key is non exportable. PIV based smartcards do not require external drivers on most modern OSes. [0]: https://developers.yubico.com/PIV/Introduction/PIV_attestation.html https://developers.yubico.com/PIV/Introduction/PIV_attestati... U2F is designed for only one algorithm and allows a lot of optimizations (e.g the private keys are not really stored on the device but rather generated from master seed and origin). That's why they are substantially cheaper than PIV devices.

hdhzy 9y ago

Client certificates are best from security perspective but lack UX (this could be fixed) and are not designed with privacy in mind. U2F on the other hand generates unique pair of keys for each origin. By default.