HTTPTimestamper builds a Request directly from a precomputed SHA-256
digest (Request{HashAlgorithm, HashedMessage, Nonce}.Marshal(), not
CreateRequest(io.Reader) which would hash the input itself), POSTs it to
a TSA, and validates that the parsed response's hash algorithm, hashed
message and nonce actually match what was sent before accepting the
token — a response that doesn't match the request isn't a valid
timestamp for that hash, regardless of whether it parses.
Uses github.com/digitorus/timestamp for the RFC-3161/ASN.1 encoding
rather than hand-rolling it.
TSA choice (open point in CLAUDE.md): FreeTSA.org for now — free,
RFC-3161-compliant, verified end-to-end with a live smoke test, but
not eIDAS-qualified. Documented as needing an upgrade to a qualified
provider (D-Trust, Bundesdruckerei, ...) before real customer use, same
treatment as the open legal questions in rules/OPEN.md.
Tests cover request/response validation without network (hash size
guard, a fake server that parses and checks the incoming request,
non-200 and malformed-response handling) plus a real integration test
against FreeTSA gated behind DEKLARIX_TSA_INTEGRATION, mirroring the
DATABASE_URL-gated pattern in internal/store.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
SHA-256 over raw asset bytes and over the canonical JSON form of
metadata (encoding/json already sorts map keys and preserves struct
field order deterministically, so no separate canonicalization library
is needed for our own fixed types). A Timestamper interface stands in
for the RFC-3161 timestamp step — no concrete implementation yet, since
which TSA to use is an open decision (CLAUDE.md "Offene Punkte") that
directly affects the archive's evidentiary weight, not a purely
technical choice to make silently.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
