[joaquinbejar]

Summary

Codex's remaining P2 from #188/#192. EncryptMethod (98) is a required field of the Logon (FIX44.xml, doc/fix_operations.md), but neither the engine's initiator nor the #93 poll driver checked it on the acknowledgement: an ack without 98 established the session.

Changes

• ironfix_session::header::check_encrypt_method and EncryptMethodProblem: 98 must be present and 0. It reports SessionRejectReason 1 (absent) or 5 (another method) with RefTagID 98, in the existing text.
• The engine initiator now refuses such an ack with a session Reject and a Logout, and fails with EngineError::LogonRejected, as it does for a bad 108.
• The acceptor uses the same check. Its Logon refusal is unchanged: a Logout with the same text. The only difference is that a non-UTF-8 value is now echoed lossily instead of shown as absent.
• The poll driver runs the same check, in the same order.
• doc/fix_operations.md, initiator step 6, documents it.

Behaviour change

An initiator now refuses a Logon acknowledgement without 98, or with a 98 other than 0. A conforming counterparty always sends 98=0.

Testing

• initiator_tests::test_ack_encrypt_method_missing_or_unsupported_fails_handshake covers both an absent 98 and 98=1.
• poll_driver_peer::test_ack_without_encrypt_method_is_rejected_and_ends_the_session covers the poll driver.
• cargo test --workspace --all-features: 2647 passed, 0 failed. fmt, clippy -D warnings, doc and check-spanish are clean.

Refs #93

[joaquinbejar]

APPROVE. The required EncryptMethod check resolves the remaining finding from PR188 and PR192. The 17 independent engine handshakes, three protocol probes, 275 session tests, seven peer tests, interop and formatting checks pass. No new findings. Submitted as COMMENT because GitHub prevents the author account from approving its own pull request.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.13208% with 10 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ironfix-example/examples/poll_driver/mod.rs	0.00%	10 Missing ⚠️

Files with missing lines	Coverage Δ
ironfix-engine/src/acceptor.rs	88.08% <100.00%> (-0.08%)	⬇️
ironfix-engine/src/initiator.rs	80.09% <100.00%> (+0.67%)	⬆️
ironfix-session/src/header.rs	100.00% <100.00%> (ø)
ironfix-example/examples/poll_driver/mod.rs	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

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