fix: author account-scoped requests with an ephemeral key, not the identity key

[Forte11Cuba]

Close #172

The three account-scoped requests (Action::LastTradeIndex, Action::RestoreSession, and the restore stage-2 Action::Orders fetch) passed identity_keys as both the identity and the trade-key argument of send_dm, so the outer kind-14 was authored by the permanent identity pubkey and the identity proof was silently dropped (mostro-core only includes it when the keys differ)

Each call site now generates a fresh Keys::generate() that authors the event, and the whole trio switches together send_dm, wait_for_dm and parse_dm_events all use the same ephemeral key, since the daemon replies NIP-44-encrypted to event.sender. identity_keys stay where the protocol wants them: inside the encrypted proof, which is what the daemon resolves the account from (event.identity).

No daemon or dependency changes, no public signature changes, and no wallet index burned (check_trade_index only covers NewOrder | TakeBuy | TakeSell). The sender != mostro_pubkey checks are untouched.

Bonus hardening on restore (the only flow with no request_id): a stale restore reply replayed by a relay used to be decryptable by the identity key and could seed outdated RestoreData; a per-run ephemeral key cannot decrypt replies addressed to earlier runs, so they can never be consumed

Two notes, neither a behavior regression:

• Each ephemeral key adds a relay subscription that lives until listener rebuild — same lifecycle per-order trade keys already follow. A future improvement could unsubscribe in prune_closed_pending_waiters.
• The restore log now prints the ephemeral key instead of the identity pubkey, aligning with the daemon's convention of keeping the persistent identity out of logs.

Verified with cargo fmt --check, cargo clippy --all-targets (clean) and the full cargo test suite (all green)

Summary by CodeRabbit

• Security & Privacy

  • Session restoration, order-detail retrieval, and trade-index synchronization now use fresh, temporary keys for requests.
  • Account identity remains securely included as encrypted proof while avoiding persistent identity-to-service links.
  • Fresh keys help prevent replies from previous restore attempts from being reused.

• Documentation

  • Added guidance explaining key usage, privacy modes, and safe handling of long-lived identity keys.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 22a63a93-b06e-4899-9d4c-6e961ca2d6c0

📥 Commits

Reviewing files that changed from the base of the PR and between 8ec3bfa and 484eb6f.

📒 Files selected for processing (3)

• src/util/dm_utils/mod.rs
• src/util/order_utils/execute_restore.rs
• src/util/sync_trade_index.rs

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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Walkthrough

Restore and last-trade-index requests now use fresh ephemeral keys for outer DM authorship and response handling. Long-lived identity keys remain encrypted identity proofs. Documentation describes the key separation and privacy rules.

Changes

Account-scoped DM privacy

Layer / File(s)	Summary
Restore ephemeral-key flow src/util/dm_utils/mod.rs, src/util/order_utils/execute_restore.rs	Restore requests and order-detail requests use fresh ephemeral keys for authorship, reply addressing, and response decryption. Identity keys remain encrypted proofs. Documentation describes the key roles and replay protection.
Trade-index ephemeral-key flow src/util/sync_trade_index.rs	Last-trade-index requests use a fresh ephemeral key for sending, waiting, and parsing responses. Identity keys remain in the encrypted proof.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 484eb

Restore and trade-index requests now use fresh ephemeral authors and reply keys while preserving encrypted identity proofs, preventing permanent identity exposure in relay-visible events and isolating restore replies between runs. No current merge-blocking risk remains.

Suggested reviewers: arkanoider

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the primary change: using ephemeral keys to author account-scoped requests instead of identity keys.
Linked Issues check	✅ Passed	The changes satisfy issue #172. The three specified requests now use fresh ephemeral keys for sending, waiting, and parsing, while identity keys remain in the encrypted proof. Restore flows also gain …
Out of Scope Changes check	✅ Passed	All code and documentation changes support the linked issue and PR objectives. No unrelated functional, dependency, daemon, or public API changes are present.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 3 files.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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_{A rabbit sends a fleeting key,
While identity sleeps unseen.
Replies hop back through moonlit air,
Old echoes find no doorway there.
Privacy blooms with every pair.}

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[Catrya]

ACK

[arkanoider]

Good pick! Well scoped, safely mergeable. LGTM!