codec/kat.go: KATEntry + KATBundle types with canonical JSON
serialization. Header field embeds params.KATHeader so every entry
carries (parameter_set, modulus_id, backend_id, hash_suite_id,
implementation, version) — required by LP-107 §"Parameter registry"
for cross-runtime equality.
codec/cmd/emit_codec_kat/main.go: emits 5 canonical entries:
1. ReadUint64Slice/happy-path/3-elements
2. ReadUint64Slice/empty
3. ReadUint64Slice/reject/lattice-issue-4-70T (regression: huge
length must be rejected by both runtimes)
4. ReadUint16Slice/happy-path/5-elements
5. ReadUint32Slice/happy-path/4-elements
Each entry records:
- InputHex: the wire-format bytes the Reader consumes
- OutputHex: the canonical output byte stream (or "REJECTED")
- OutputSHA256: commitment for fast cross-runtime equality
codec/kat_test.go: TestKATBundle_RoundTrip replays every bundle
entry through the Go Reader and asserts byte-equality + SHA-256
commitment match. PASS in 0.29s.
codec/testdata/codec_kat.json: the Go-emitted bundle. The C++ side
at luxcpp/crypto/math/test/codec_cross_runtime_test.cpp loads the
same file and replays every entry; in this commit, all 5 entries
PASS byte-equal between runtimes.
This closes LP-107 Phase 7 for codec/. Subsequent commits extend the
gate to modarith/, ntt/, poly/, sample/ KATs.
ntt, poly, rns, sample
Eight pure-Go reference packages that own the canonical semantics of
every cryptographic-math primitive Lux protocols share. Backends
(AVX2 / NEON / cgo+C++ / CUDA / Metal / WGSL) plug in behind the
substrate; KATs gate byte-equality across them.
Packages added:
* params/ — ModulusID, NTTParamID, FHEParamID, PulsarParamID,
HashSuiteID, BackendID; KATHeader required-fields
schema. Stable string IDs; renaming is a breaking
change.
* backend/ — Policy enum (PureGo / NativeCPU / GPUPreferred /
GPURequired); Resolve(policy, registered) returns the
BackendID per LP-107's fallback chain. GPURequired
returns ErrUnavailable when no GPU backend is
registered.
* codec/ — Bounded readers (closes lattice issues #2 + #4 DoS
class permanently). Limits + LimitError + Reader.
ReadUint{16,32,64}Slice all reject the 70T-element
attack input before allocating; depth + frame-bytes
caps; iterative (no recursion). Regression test
TestReadUint64Slice_RejectsHugeLength encodes the
original lattice issue #4 input.
* modarith/ — Modulus type with QInv, R2, Barrett constants
(computed via math/big once per modulus). AddMod /
SubMod / MulMod (Div64 reference path). MontMulMod /
ToMontgomery / FromMontgomery cross-checked against
MulMod across 100 random Pulsar-Q pairs.
ReductionMode enum byte-equal to lattice/types.
* ntt/ — Service + Backend interface; pure-Go backend
delegates to lattice/v7/ring.SubRing.NTT/INTT (the
canonical Lattigo-derived Montgomery NTT body — no
re-implementation, just dispatch). Round-trip +
batch + determinism tests on Pulsar N=256.
* poly/ — Add / Sub / ScalarMul / PointwiseMul (NTT-domain) /
negacyclic Mul (NTT round-trip). Composes modarith +
ntt; no lower-level reach.
* rns/ — Basis(Moduli, Name) for FHE RNS chains. Single +
two-prime construction validated; rejects even moduli.
Phase 3 will add basis-extension and modulus-switching.
* sample/ — Uniform (rejection sampling, mask-and-retry); Ternary
(density + sign byte); CenteredBinomial (popcount
difference); DiscreteGaussianRejection (6-sigma cutoff).
All take an io.Reader so callers can KAT-replay.
Architecture invariants enforced in package docs:
- Go is the canonical semantic reference.
- Backend selection MUST NOT alter transcript bytes (consensus
paths default to PolicyPureGo / PolicyNativeCPU).
- No unbounded codec readers anywhere near wire formats.
- No re-implementation: where lattice/v7/ring already owns the
canonical body, we delegate, not fork.
- One ID space; renaming is a breaking change.
Test posture: 8/8 packages green via `GOWORK=off go test ./...`.
Phases 3-7 (queued):
3. lattice consumes math
4. pulsar consumes lattice + math
5. fhe consumes math
6. luxcpp/crypto/math native backend mirror
7. cross-runtime KAT release gate
See SUBSTRATE.md for the full posture and migration plan; full LP at
~/work/lux/lps/LP-107-lux-math-substrate.md.
Hanzo AI