MicrOBU/microbu-esp32c5/external/vanetza-idf/docs/idf/evidence/enrolment-authorization-01/analysis.md

enrolment-authorization-01: EA/AA enrolment and authorization over HTTP on localhost

TS 102 941 V2.2.1 clause 6.2.3: an ITS-S obtains an enrolment credential (EC) from its EA and, using that EC, an authorization ticket (AT) from an AA that in turn validates the EC's entitlement with the EA ("AA <-> AA" of the security architecture's Online PKI roles box). vanetza_idf::pki already built and parsed every message in-process (test_pki.cpp); nothing carried the bytes between two separate processes over a real transport, which is exactly the transport half of GAP-PKI-001 (docs/idf/conformance.md). Here the lab EA and AA run as a real localhost HTTP server (tools/local_pki.py) and a lab station drives the whole enrol-then-authorize sequence against it as a real client (tools/pki_client.py), both shelling out to vidf_issue's new enrol-*/authorize-*/ea-respond/ aa-respond subcommands for the actual TS 102 941 cryptography.

Closing the transport also surfaced two bugs that never mattered while the EA/AA side only ran in-process against keys the same test already knew:

• TrustDomain::issue_authority generated a fresh ECIES encryption key for every EA/AA certificate and embedded the public half, but discarded the private half -- every EA/AA vidf_issue ever produced could never actually decrypt a real request. Fixed by returning it through an out-param, persisted as <id>.ekey.
• The library's copy_curve_point (reading a wire verification key back out of a certificate) leaves .y empty for the compressed form the wire always uses, recording only the parity. Code that takes such a key and blindly copies .x/.y into a new certificate (as issuing one for a station's requested key must) silently embeds the wrong point about half the time. Fixed in the new authority-side public_key_of by decompressing (vanetza_idf::ecc::decompress) before the key is used to issue anything.

File	Content
ROOT.oer	throwaway lab root, vidf_issue root
EA.oer	EA under the root, vidf_issue authority (with .ekey alongside, not copied here)
AA.oer	AA under the root, vidf_issue authority
EC.oer	the enrolment credential ea-respond issued for the station's requested key
AT.oer	the authorization ticket aa-respond issued after validating EC.oer's entitlement with the EA
server.log	local_pki.py's log of the two requests it served

Commands

vidf_issue root      --key root.pem --name "demo root" --id ROOT --out chain
vidf_issue authority --issuer chain/ROOT.oer --issuer-key root.pem --name "demo EA" --id EA --out chain
vidf_issue authority --issuer chain/ROOT.oer --issuer-key root.pem --name "demo AA" --id AA --out chain

python tools/local_pki.py --issue-tool build/vidf_issue \
    --ea chain/EA.oer --ea-key chain/EA.vkey --ea-enc-key chain/EA.ekey --canonical-key canonical.pem \
    --aa chain/AA.oer --aa-key chain/AA.vkey --aa-enc-key chain/AA.ekey \
    --dir issued --port 8092

python tools/pki_client.py --issue-tool build/vidf_issue --pki http://127.0.0.1:8092/ enrol \
    --ea chain/EA.oer --canonical-key canonical.pem --its-id vidf-http-demo \
    --out EC.oer --out-key EC.vkey
python tools/pki_client.py --issue-tool build/vidf_issue --pki http://127.0.0.1:8092/ authorize \
    --ea chain/EA.oer --aa chain/AA.oer --ec EC.oer --ec-key EC.vkey \
    --out AT.oer --out-key AT.vkey

vidf_issue verify EC.oer chain/EA.oer chain/ROOT.oer   # chain verifies
vidf_issue verify AT.oer chain/AA.oer chain/ROOT.oer   # chain verifies

A tampered EnrolmentRequest (one octet flipped) fed to ea-respond directly is refused: "request did not decrypt/verify/decode; nothing was issued", exit 1 -- local_pki.py turns that into HTTP 400 rather than fabricating a response.

Result

• Both HTTP round trips completed (server.log: two POST ... 200), and both resulting certificates verify their full chain to the same lab root (vidf_issue verify, signature + validity + region + permission-consistency checks, IEEE Std 1609.2 clause 5.1.2).
• The AA's entitlement check of the EC (aa-respond internally calling the new validate_entitlement, decrypting the EC's forwarded signature with the EA's key and checking it against the SharedAtRequest hash, clause 6.2.3.3.1) succeeded against the real EC.oer this run actually issued -- not a same-process fixture the test already trusted.
• vidf_tests (929 checks) is unaffected: test_pki.cpp was refactored to call the same shared pki_authority parsing/response code this evidence exercises operationally, rather than duplicating it inline.

Scope

This closes the ad hoc/manual-testing half of GAP-PKI-001: a real HTTP transport for enrolment and authorization now exists and is proven correct end to end. It does not run the official ETSI AtsPki suite (163 cases, still 0 executed) -- that needs the licensed/compiled test-system binary and a TTCN upper-tester adapter (the build_etsi_btp_adapter.py/etsi_btp_adapter.cpp pattern), a separate effort. Nor does it implement the phone's own TS 102 941 client (architecture/diagrams/microbu-architecture-2b-revision-b-security.drawio): today's flow is lab tooling standing in for both the EA/AA and the requesting station, not new C5/phone firmware.