intx/LUXFI-FORK.md

LUXFI-FORK

This is a luxfi-maintained fork of chfast/intx.

Pin

• Upstream tag: v0.15.0
• License: Apache-2.0 (see LICENSE)

Why this fork exists

intx is a header-only extended-precision integer C++ library used by luxcpp/crypto for Montgomery arithmetic in:

• bn254/
• secp256r1/
• modexp/
• evm256/
• kzg/

These bodies all #include <intx/intx.hpp>. The library is currently inline-vendored at luxcpp/crypto/deps/intx/. After fork swap (LP-137 sibling work), it will be pulled via FetchContent from luxfi/intx.

Owning the fork pins the Montgomery primitives so upstream API or behavior changes cannot silently affect curve arithmetic on chain.

Sync policy

• Track upstream tagged releases only.
• Pull tags into sync/<tag> branches. Re-run all luxcpp/crypto cpp/ bodies against the new pin (every consumer listed above). Merge to main only when all KATs pass.

Maintainer

luxfi crypto team. Contact via the luxfi/crypto repo.