[Gopalakrishnan Nallasamy (GopalakrishnanN)]

Description

Add a standalone macOS Objective-C XCTest target for the complete compiled-model/context workflow:

• Compile the two-input Mul fixture through the executable example plugin EP.
• Encrypt and persist the compiled ONNX and external context using AES-256-CBC with encrypt-then-HMAC-SHA256, independent random keys, random IVs, and authenticated asset names.
• Release compilation state, decrypt stored assets, restore context through the public Objective-C read block, and check numerical inference for two input sets.
• Reject wrong authentication keys, changed ciphertext, mismatched authenticated names, missing callbacks, callback authentication failures, and invalid context payloads.
• Keep plugin-dependent sources outside the objectivec/ tree copied to the Swift package repository. The separate onnxruntime_objc_encryption_test target owns its plugin dependency, Security framework, model resource, and CTest environment; ordinary Objective-C tests have none of those extra dependencies.
• Confine native registration, device selection, and compilation to a test-only fixture adapter. Loading, read-block registration, tensors, and inference use public Objective-C APIs. Public compilation and provider-library registration APIs are not added by this test PR.
• Use explicit provider-options types for Apple Clang, and always remove the temporary directory even when native unregistration throws. Add testCleanupRemovesPlaintextWhenUnregisterThrows to cover that failure path.

The public Objective-C session constructor is path-only. Decrypted compiled ONNX is temporarily persisted during loading and removed during cleanup; external context plaintext remains in memory. This does not establish no-plaintext-at-any-time coverage.

Dependency: #33216. This branch contains the identical shared fixture prerequisite commit so it can receive normal PR CI against main. Merge #33216 first; its changes should then disappear from this PR's diff.

Validation

• clang-format --dry-run --Werror onnxruntime\test\platform\apple\ort_encrypted_ep_context_test.mm onnxruntime\test\platform\apple\ort_ep_context_fixture.h onnxruntime\test\platform\apple\ort_ep_context_fixture.mm: passed.
• git diff --check: passed.
• CMake configuration-branch harness for full macOS, minimal macOS, and iOS: 3 passed. It verifies source isolation, ordinary-test dependencies/resources, and separate-target CTest/plugin/model wiring. Apple targets/framework discovery are mocked; this is not an Apple build.
• Apple compilation and XCTest execution: NOT RUN locally. This Windows workspace has no Xcode or Apple runtime. Fresh PR CI must provide runtime confirmation.
• Required Apple validation after building: ctest --test-dir <Apple build directory> -C Release -R '^XCTest.onnxruntime_objc_encryption_test$' --output-on-failure. Both the encrypted-inference test and unregister-failure cleanup regression must execute successfully. The target fails rather than skips if its required plugin path is missing.

Existing macOS full-build CTest execution discovers the separate target automatically. No encrypted-workflow execution is claimed for ordinary XCTest runs, iOS, or the Swift package.

Motivation and Context

Follow up the APIs from #32265 and merged Objective-C binding #32309 with real compiled-state transport and numerical inference coverage. Ordinary model loads and callback-only tests do not prove restored external EPContext execution.

The isolation addresses the Swift package synchronization constraint without adding new public APIs or requiring the copied Objective-C test suite to depend on ORT's example plugin target.

[Copilot]

🟡 Changes recommended

The tamper control modifies the HMAC tag rather than ciphertext, so the stated altered-ciphertext case is not covered.

2 open findings

• Test flips HMAC tag instead of ciphertext · New
• Mislabels cross-platform plugin as Windows-only · New

What changed in this PR

Adds Objective-C end-to-end coverage for encrypted compiled EPContext model restoration and inference, building on #33216.

Changes:

• Adds an executable Mul EPContext fixture and generated model.
• Adds encrypted Objective-C compilation, restoration, negative, and inference tests.
• Provisions the plugin/model for macOS XCTest and documents the workflow.

File	Description
.gitignore	Tracks the generated ONNX fixture.
cmake/​onnxruntime_objectivec.cmake	Links Security.framework and provisions test assets/plugin.
docs/​design/​Compiled_Model_Encryption.md	Documents binding workflows and Objective-C coverage.
objectivec/​test/​ort_encrypted_ep_context_test.mm	Implements encrypted EPContext integration testing.
onnxruntime/​test/​autoep/​library/​example_plugin_ep/​ep.cc	Serializes and restores executable Mul context.
onnxruntime/​test/​autoep/​library/​example_plugin_ep/​ep.h	Adds restored-kernel state and configuration.
onnxruntime/​test/​autoep/​library/​example_plugin_ep/​ep_factory.cc	Parses the execution-test option.
onnxruntime/​test/​testdata/​encrypted_ep_context_mul.py	Generates the two-input Mul model.
onnxruntime/​test/​testdata/​encrypted_ep_context_mul.onnx	Provides the bundled source-model fixture.

🧠 Review effort: Balanced

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[Gopalakrishnan Nallasamy (GopalakrishnanN)]

Fixed both macOS Debug -Werror=sign-compare errors by making expected XCTest counts NSUInteger, plus the shared Linux fixture overload ambiguity. Pushed 8de1640. Corrected C++ fixture call passed MSVC C++17 /W4 /WX syntax validation; Apple XCTest compilation requires the newly triggered macOS CI. No old-head runs were manually retriggered.

[Gopalakrishnan Nallasamy (GopalakrishnanN)]

Retried only the confirmed DNS-failed current-head iPhone simulator job after the macOS workflow completed. Original setup error: getaddrinfo ENOTFOUND github.com while downloading CMake. No stale-head or green jobs were retriggered.

[Tianlei Wu (tianleiwu)]

The Objective-C XCTest (ort_encrypted_ep_context_test.mm) and CMake wiring are well structured, with a clean AES-256-CBC + encrypt-then-HMAC-SHA256 construction and thorough negative controls.

Requesting changes for one blocking compile issue on Apple Clang: objectivec/test/ort_encrypted_ep_context_test.mm line 147 still calls native.AppendExecutionProvider_V2(nativeEnv, {*device}, {}) with {} as the third argument, which is ambiguous on Clang (the same issue fixed for test_execution.cc in fcdaaa40eb).