[defisym]

Existing Encryption users relied on Windows BCrypt and the historical Fusion class. This PR replaces the implementation with one portable C++17/OpenSSL core while retaining the compatibility methods, Fusion event interfaces and existing asset format.

Based on master b1a0551f after the GeneralDefinition split in #103. FFMpeg playback/AVIO changes remain in dependent PR #102. Existing commits are replayed onto master; review follow-ups remain separate commits.

Module layout

The outer Encryption.h / Encryption.cpp remain the compatibility entry point; EncryptionStream.h keeps the historical push API. The implementation, C adapters, VS projects, CMake and tests now live under _DeLib/Encryption/: Core.h, KeyGen.h, CAPI.h/.cpp, Encryption.sln and Encryption.vcxproj. The library/CMake target is encryption; EncryptionPortable naming and the old directory are removed. Installed headers retain this hierarchy, so repository and installed consumers use the same include paths. C adapters are consolidated into one CAPI.h and one CAPI.cpp, including shared callback declarations and private error translation; the eight split adapter/helper files are removed. All 29 exported C function names and definitions are unchanged.

Changes

• Shared incremental AES-128-CBC/PKCS#7, hashes and seekable DecryptReader. The reusable core has no FFmpeg dependency.
• Encryption.h/.cpp compatibility facade and C ABI. Windows SDK EFS undef guards prevent aliases from renaming EncryptFile/DecryptFile; BCrypt and Windows type aliases are no longer required.
• Arbitrary-length KeyGen preserves the original Win32/Win64 seed rules and existing ciphertext bytes. Empty input retains bytes 00..0f.
• Generic UTF conversions now live in UnicodeConversion.h, exposed globally through GeneralDefinition: to_utf16_string (UTF-8/native-wide overloads) and to_utf16_bytes (UTF-16LE without BOM). This standalone C++17 header has no OpenSSL, Windows API or iconv dependency. Encryption translates conversion errors to its existing argument errors. EncryptionText.h is removed.
• File call sites use std::filesystem::path directly. No custom path-conversion helper remains. C file APIs accept caller-owned FILE handles or callbacks; mobile bridges select their own encodings/file opening.
• Compatibility cleanup removes unused constants/state, uses Mode in Encrypter and adds ClearEncryptData. Valid empty data remains distinct from cleared input, including standard empty-file hashes. Directly methods retain incremental reads and complete in-memory output.
• VS EncryptDependencies automatically downloads and verifies the repository's fixed OpenSSL SDK for all nine consumers. Normal builds do not run vcpkg; source builds remain an explicit option.

Review follow-up

• MSVC-only SAL postconditions describe require's normal-return contract. Zero-length file reads return before the non-null output requirement, making the fread path explicit to the analyzer.
• Use if constexpr for native wchar_t width and explicit smart-pointer boolean conversion. Guard the MSVC warning pragma on other compilers.
• Move the bounded 64 KiB transform/file-hash scratch buffers to the heap. The C file-hash API returns its existing out-of-memory result if allocation fails.
• Propagate SaveFile failure from Encrypter's helper instead of returning true after a failed write. A local harness compiled the actual helper and checked invalid destinations plus exact existing-asset round trips.
• Added actual MSVC /analyze builds, treating analysis warnings as errors, and C file-hash checks for both abc and EOF/empty input.

Validation

• Native Release and ASan/UBSan core suites pass, including frozen Win32/Win64 KeyGen vectors, Unicode, C ABI, >4 GiB offsets, streaming and seeks.
• Key 12345678ABCDEFGH decrypts all 1,641,882 original JPEG bytes and reproduces all 1,641,888 old ciphertext bytes.
• Chinese-path save/open/hash/encrypt/decrypt checks pass using filesystem paths directly.
• Shared helper regressions and 22 standalone C++17 Unicode checks pass on Linux. Installed public headers compile independently with C++17.
• Dependent MemBuf/AVIO tests also pass under ASan/UBSan. Local leak detection is disabled in the ptrace-limited environment.
• CI covers VS/MSBuild Win32/x64 Release/Debug, Linux sanitizers and macOS; shared-header CI also covers Visual Studio. Current-head Linux/macOS tests, shared-header Windows/Linux checks, and VS Win32/x64 Release/Debug builds and tests have passed. Win32 and x64 native MSVC analysis also passed with warnings treated as errors (run). Source-SDK rebuild/package stages are still running. The module-layout follow-up has also passed clean static/shared builds, Release and ASan/UBSan regressions, and installed C/C++ consumer smoke tests; the renamed VS projects have also passed Win32/x64 Release/Debug builds, runtime tests and /analyze, alongside Linux/macOS CI (module-layout run).

Core build instructions · Dependency setup · Pinned SDK release

Manual acceptance

• Build consuming extensions with VS and load the rebuilt .mfx files in Fusion.
• Exercise existing encrypted image/configuration/video assets through their existing actions.

C++ class binary layout is not retained. Full Fusion runtime and device packaging remain separate from native tests. Merge this PR before #102.