This PR adds FIPS 140-3 compliant SHA-256 hashing as an alternative
to blake3 for multimodal content hashing. This enables vLLM usage in
government, healthcare, and financial environments that require
FIPS-approved cryptographic algorithms.
Changes:
- Add _Sha256Hasher wrapper class with consistent interface
- Add _Blake3Hasher wrapper class for optional blake3 usage
- Add _create_hasher() factory function for hasher selection
- Add VLLM_USE_FIPS_HASHING environment variable control
- Automatic fallback to SHA-256 when blake3 is unavailable
- Add comprehensive test suite for FIPS hashing functionality
Fixes#18334🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: yurekami <249254018+yurekami@users.noreply.github.com>
