Each request to a gated endpoint now triggers a fresh FIDO2 assertion.
Challenge = SHA256(url|method|nonce) — bound to the specific resource.
The self-contained assertion bundle lets the server verify independently
without calling back to the phone.
- fido2_ops.dart: GetAssertionResult gains clientDataJson; getAssertion
accepts optional challenge override
- proxy_service.dart: _handleAuthGetToken accepts {url,method,nonce},
derives challenge, runs card assertion, returns b64url bundle
- filter_proxy.dart: _getAuthToken(uri, method) generates nonce and
passes binding fields to Component 2
- component3/phone.go: stateless GetTokenForRequest(url, method) —
no session caching, no expiry, one card touch per request
- component3/proxy.go: use GetTokenForRequest
- component3/main.go: remove --user flag (Component 2 picks enrolled user)
- k_server_app.py: _verify_assertion_token() — verifies path+method
match, challenge claim, and ECDSA-P256 signature; accepts both
legacy X-Proxy-Token and new Bearer assertion tokens
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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