protocol-v2 | decentralized non-custodial liquidity markets | Blockchain library

The document for running Git wire protocol v2 states that in order to invoke git-upload-pack with protocol v2, one needs to run it with an environment variable GIT_PROTOCOL containing version=2. I do that by running in terminal:

There are many sources that say FIDO2/CTAP2 is backward compatible with U2F:

...all previously certified FIDO U2F Security Keys and YubiKeys will continue to work as a second-factor authentication login experience with web browsers and online services supporting WebAuthn. - Yubico

But after looking at the specifications, I'm having trouble seeing how that actually works in practice. Specifically, it seems like there is a mismatch between FIDO2's relying party identifier and U2F's application identity.

In U2F, the application identity is a URL, like https://example.com. SHA-256 of the application identity is called the application parameter. The application parameter is what is actually sent to the authenticator during registration and authentication.

In FIDO2, the equivalent seems to be the relying party identifier, which is defined to be a domain name, like example.com.

The relying party identifier and the application identity serve the same purpose in both FIDO2/CTAP2 and U2F. However, CTAP2 authenticators get the relying party identifier directly as an UTF8 string, whereas U2F authenticators only get a SHA-256 hash of the application identity (the application parameter).

The FIDO documentation for CTAP describes how CTAP2 maps onto CTAP1/U2F. In it, they simply treat the relying party identifier directly as the application identity:

Let rpIdHash be a byte array of size 32 initialized with SHA-256 hash of rp.id parameter as CTAP1/U2F application parameter (32 bytes)

This seems inconsistent. Let's say I were example.com, and I adopted U2F second-factor authentication early on. My application id would be https://example.com, so my original U2F application parameter would be SHA256("https://example.com"):

I am making a mobile authenticator which supports CTAP BLE to communicate with WebAuthn. I follow this document: https://fidoalliance.org/specs/fido-v2.0-id-20180227/fido-client-to-authenticator-protocol-v2.0-id-20180227.html#ble-protocol-overview

The Protocol Overview as following:

1. Authenticator advertises the FIDO Service.

2. Client scans for authenticator advertising the FIDO Service.

3. Client performs characteristic discovery on the authenticator.

4. If not already paired, the client, and authenticator SHALL perform BLE pairing and create an LTK. Authenticator SHALL only allow connections from previously bonded clients without user intervention.

5. Client checks if the fidoServiceRevisionBitfield characteristic is present. If so, the client selects a supported version by writing a value with a single bit set.

6. Client reads the fidoControlPointLength characteristic.

7. Client registers for notifications on the fidoStatus characteristic.

8. Client writes a request (e.g. an enroll request) into the fidoControlPoint characteristic.

9. Optionally, the client writes a CANCEL command to the fidoControlPoint characteristic to cancel the pending request.

10. Authenticator evaluates the request and responds by sending notifications over fidoStatus characteristic.

11. The protocol completes when either:

    • The client unregisters for notifications on the fidoStatus characteristic, or:
    • The connection times out and is closed by the authenticator.

At step 8, I receive the message like this: 0x83000700030000000000, I understand that

0x83 is MSG command

0x0007 is length of data

00030000000000 is data

When I receive such a message, I don't know what to response to WebAuthn as step 10 says "Authenticator evaluates the request and responds by sending notifications over fidoStatus characteristic."

Just wanted to know whether github server supports git wire protocol-v2? - https://opensource.googleblog.com/2018/05/introducing-git-protocol-version-2.html - https://github.com/git/git/blob/master/Documentation/technical/protocol-v2.txt