This directory contains the submitted compact Scloud+ implementation layout.

It contains the portable Reference tier and the optimized AVX2/NEON tier used for the submitted KEM instances.

Reference_Implementation/   portable Reference tier
Optimized_Implementation/   AVX2 or NEON Optimized tier
_shared/                    shared API_PKC facade and algorithm kernels

Each security level has a single build entry under {Reference_Implementation,Optimized_Implementation}/Scloudplus-*/kem/. Those leaf directories intentionally contain only the build files and the level-specific parameters.h. Shared code includes scloudplus_param_common.h, which imports the leaf parameters.h through the build entry include path.

parameters.h contains only the constants fixed by the security level: dimensions, sampler parameters, message-code parameters, byte lengths, and API sizes. Primitive family and backend choices are supplied by CMake compile definitions, or equivalently by a direct Makefile/embedded build that provides the same definitions.

Select the primitive family with SCLOUDPLUS_FAMILY; it defaults to AES when omitted.

• Reference tier: backend is fixed to REF.
• Optimized tier: SCLOUDPLUS_BACKEND=AUTO selects AVX2 on x86_64/AMD64 and NEON on AArch64/ARM64. Pass SCLOUDPLUS_BACKEND=AVX2 or SCLOUDPLUS_BACKEND=NEON for explicit backend testing.

The public-matrix byte format is fixed to packed10 in this submission, so it is not a build option.

Example:

cmake -S Reference_Implementation/Scloudplus-128/kem \
      -B build/ref128-aes \
      -DCMAKE_BUILD_TYPE=Release \
      -DSCLOUDPLUS_FAMILY=AES
cmake --build build/ref128-aes
./build/ref128-aes/test_scloudplus

Public targets exposed by each leaf CMake entry:

• test_scloudplus
• kem_loop_scloudplus
• tamper_scloudplus
• kat_kem_scloudplus
• verify_kat_kem
• bench_scloudplus
• scloudplus_kem

For AArch64 SM3 optimized builds, the compiler must support the ARM SM3/SM4 intrinsics used by neon/sm3_aarch64.c. The optimized CMake entries pass -march=armv8.2-a+sm4 on non-Darwin AArch64 builds; this is the minimum target feature set needed by GCC 10-compatible SM3/SM4 intrinsic headers. Darwin arm64 builds use the fallback path in neon/sm3_aarch64.c because Apple clang does not provide the same intrinsic interface.