ml-dsa: use ctutils for constant-time selection, avoid branches#1245
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tarcieri merged 10 commits intoRustCrypto:masterfrom Mar 26, 2026
Merged
ml-dsa: use ctutils for constant-time selection, avoid branches#1245tarcieri merged 10 commits intoRustCrypto:masterfrom
tarcieri merged 10 commits intoRustCrypto:masterfrom
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I'd suggest just using Whenever stable rustc has support for the LLVM intrinsic, we can add support to |
tarcieri
reviewed
Mar 19, 2026
Remove ct.rs wrapper trait/module, use ctutils::CtSelect directly at call sites per maintainer feedback. Resolve Cargo.lock conflict by accepting upstream. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
tob-scott-a
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Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
tarcieri
approved these changes
Mar 26, 2026
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Uses
ctutils::CtSelectdirectly at call sites to replace secret-dependent branches with constant-time selection (cmov/CSELintrinsics). No wrapper trait or macro.Changes
algebra.rs:BarrettReduce::reduce,decompose,mod_plus_minus, andinfinity_normuseu32::ct_selectinstead ofif/elsebranches on secret valueshint.rs:use_hintusesu32::ct_selectinstead of nested branches onr0andhCargo.toml: addsctutilsdependencySee: https://blog.trailofbits.com/2025/12/02/introducing-constant-time-support-for-llvm-to-protect-cryptographic-code/