base64-ng 0.5.0

base64-ng v0.5.0

Highlights

• Added AVX-512 VBMI candidate detection and audit reporting while keeping scalar as the only active backend.
• Hardened runtime backend reporting with structured snapshots, CPU feature requirements, and scalar-only deployment policy checks.
• Added inactive AVX-512, AVX2, and NEON prototype checks with scalar-equivalence evidence.
• Strengthened stream decoder/encoder hardening for framed payloads and sensitive buffer cleanup.
• Replaced stream reader allocator-backed queues with fixed-size internal queues that clear consumed slots and wipe full queue capacity on drop.
• Hardened constant-time-oriented decoding with opaque malformed-content errors and integer byte-mask helpers.
• Expanded release gates for reserved features, SIMD boundaries, packaged scripts, cross-target builds, SBOMs, and reproducible package/build checks.
• Added a zero-dependency roadmap for MIME/PEM/bcrypt profiles, custom alphabets, validation-only APIs, secret wrappers, and future high-assurance work.

Security

• Default runtime dependency graph remains zero external crates.
• Scalar execution remains the only active backend.
• Unsafe code remains isolated to the SIMD admission boundary.
• Clear-tail and stream cleanup APIs provide best-effort buffer-retention reduction.
• Constant-time-oriented APIs still do not claim a formally verified cryptographic constant-time guarantee.

Verification

Passed release gate for:

• formatting
• clippy
• default/all-features/no-default-features tests
• doctests and docs
• Miri
• nextest
• cargo-deny
• cargo-audit
• license inventory
• fuzz/perf harness checks
• cross-target checks
• SIMD feature-bundle checks
• SBOM generation
• reproducible package/build

Kani proof execution is currently skipped because installed Kani bundles rustc 1.93.0-nightly, while this crate requires Rust 1.95.