* ed25519: add 128-bit NAF path
Add Scalar::non_adjacent_form_128 and use it in the serial and vector triple-base verifier paths for scalars known to fit in 128 bits. The helper computes only the HEEA-readable digit range instead of producing a full 256-entry NAF array for each scalar.
Benchmark notes:
- Ran this repository's Criterion benchmark program, benches/bench.rs, filtering to Single Verification, pinned to CPU 4 with 1s warmup, 2s measurement, and sample size 10.
- local_verify_zebra estimate was 19.740 us, with 95% CI 19.686..19.789 us.
- master measured 20.051 us, with 95% CI 19.938..20.134 us, so this branch was about 1.55% faster in that run.
* Use 128-bit NAF in triple-base paths
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Co-authored-by: zz-sol <allaboutshop10@163.com>
* Add prechecked optimized triple-base mul
Introduce a prechecked 128/128/256 optimized path for vartime triple-base multiplication: vartime_triple_base_mul_128_128_256 now checks whether a1 and a2 fit in 128 bits and falls back to general multiplication if not. Add vartime_triple_base_mul_128_128_256_prechecked and corresponding serial/vector backend implementations (renamed to *_prechecked). Add scalar_fits_in_128_bits helper and update callers (verification_key) to use the prechecked path. Update docs/comments and add a test to ensure full-width scalars are handled by the fallback path.
* bring back the docs
* CI
Add a static AVX2 NafLookupTable5<CachedPoint> for B * 2^128 and use it from the vector triple-base verifier path instead of rebuilding that table every verification.
Benchmark notes:
- Ran this repository's Criterion benchmark program, benches/bench.rs, filtering to Single Verification, pinned to CPU 4 with 1s warmup, 2s measurement, and sample size 10.
- local_verify_zebra estimate was 19.382 us, with 95% CI 19.327..19.426 us.
- master measured 20.051 us, with 95% CI 19.938..20.134 us, so this branch was about 3.34% faster in that run.
The triple-base verifier splits b into zero-extended 128-bit halves, so b_lo and b_hi are already canonical. Add a crate-private unchecked constructor and use it for that internal AVX2 path.
Benchmark notes:
- Ran this repository's Criterion benchmark program, benches/bench.rs, filtering to Single Verification, pinned to CPU 4 with 1s warmup, 2s measurement, and sample size 10.
- local_verify_zebra estimate was 19.996 us, with 95% CI 19.862..20.077 us.
- master measured 20.051 us, with 95% CI 19.938..20.134 us, so this branch was about 0.27% faster in that run.
