{
  "title": "Confirm or source a verified browser/WASM-capable OMEMO2 backend for the Web client endpoint",
  "reason": "S00-004 acceptance requires establishing legacy/OMEMO2 AND worker/wasm AND persistence without a homegrown ratchet. Reproduced (this run) probes and live public-registry queries confirm only the audited session/ratchet engine + persistence are verified (@signalapp/libsignal-client@0.105.0, Node native addon, zero .wasm). The browser/worker/WASM deployment and the OMEMO/OMEMO2 wire layer are not available from any maintained package on the reachable registry (@signalapp/libsignal, @converse/omemo, @xmpp/omemo, omemo2, omemo-js, omemo-client, omemo-top, omemo-wasm all E404). ENC-009 forbids a homegrown algorithm/ratchet and ENC-011 forbids substituting media AES-GCM for the OMEMO2 wire format, so the spike cannot synthesize a browser backend inside S00-004 scope.",
  "reproduction": "cd experiments/0003-crypto-library && node session-probe/smoke.mjs (exit 0, SMOKE_PASS, 631-byte byte-for-byte session record) shows session/ratchet+persistence verified; node session-probe/wasm-unsupported.mjs (exit 2, wasmFiles:0, prebuilds native *.node only) shows browser/worker/WASM NOT established. npm view on live public registry: @signalapp/libsignal-client=0.105.0; @signalapp/libsignal=@converse/omemo=@xmpp/omemo=omemo2=omemo-js=omemo-client=omemo-top=omemo-wasm=E404. Details: see this run handoff and ADR 0003.",
  "role": "crypto",
  "reviewer_role": "security",
  "scope": [
    "docs/decisions/0003-crypto-library.md"
  ],
  "outcome": "One independently reviewed, traceable primary-source outcome that establishes a verified browser/worker/WASM-capable OMEMO2 backend (a maintained library with a real web/WASM build and an OMEMO2/S ce-format mapping, or an approved external library/provider decision with license + support + browser constraints), preserving the verified audited session/ratchet engine and persistence from the existing spike, without a homegrown ratchet or ENC-009/ENC-011 bypass.",
  "steps": [
    "Read S00-004 blocker evidence, ADR 0003, and accepted ENC-003/ENC-009/ENC-011 with ADRs 0000-0002.",
    "Confirm the residual browser/worker/WASM OMEMO2 backend is unavailable from any maintained package on the reachable registry (reproduce wasm-unsupported probe and npm view queries).",
    "Source or confirm a maintained browser/worker/WASM-capable OMEMO2 encryption layer: verify its web/WASM build, license, primary-source docs, support, and an OMEMO2 wire mapping against ENC-011; or record the concrete external product/administrative decision (library, provider, or license acceptance) required to bring such a backend in.",
    "Run a focused known-answer OMEMO2 roundtrip in the web-compatible target and record actual results (or record an unsupported format blocker, not success) and update docs/decisions/0003-crypto-library.md; submit evidence and handoff for independent security review."
  ],
  "acceptance": [
    "A browser/worker/WASM-capable OMEMO2 backend is established with a real, verified web build and an OMEMO2 wire mapping from traceable primary sources, or an explicit external decision (with specific requested input) is recorded that unblocks sourcing it.",
    "The OMEMO2 wire-format mapping does not bypass ENC-009/ENC-011 client-endpoint encryption.",
    "No homegrown ratchet, no spec/plan/shared-contract change without plan, no secrets in evidence, and no out-of-scope edits; unsupported format recorded as blocker, not success."
  ],
  "checks": [
    "Known-answer OMEMO2 roundtrip in the web/WASM target, or a traceable upstream/external decision covering ENC-009/ENC-011.",
    "Web/WASM asset presence verified (non-zero real footprint), license and support checked.",
    "Independent security review confirms no bypass and no unsupported format counted as success."
  ],
  "depends_on": [],
  "requires_user_input": true
}