Crate keccak_rhdl

Expand description

Legacy Keccak-256 primitives for the HashSigsRS compatibility profile.

This crate deliberately implements Keccak-256, whose final partial block uses the legacy 0x01 domain byte. It does not implement FIPS 202 SHA3-256, whose corresponding byte is 0x06. Confusing those encodings produces unrelated digests and therefore incompatible HashSigs keys and signatures.

The hardware-facing foundation is split into three layers:

keccak_round is one fully combinational Keccak-f[1600] round. Its rotation offsets and lane destinations are compile-time constants.
keccak_f1600 composes all 24 rounds and is useful as a correctness oracle and an RTL generation target. It is not the intended area-efficient implementation.
IterativeKeccak stores one 1,600-bit state and applies one round per cycle. A request accepted while IterativeOutput::ready is true emits a one-cycle IterativeOutput::done pulse after exactly 24 round cycles.

LegacyKeccak256 is a software/block-packing model used by tests and by downstream schedulers. It exposes 136-byte rate blocks in the same little-endian lane order consumed by the RHDL absorption kernel. This keeps variable-length byte buffering out of the permutation core while covering every HashSigs message size (32, 35, 64, and 2,144 bytes).

§Evidence boundary

The tests exercise the Rust model, RHDL VM, lowered RTL VM, and emitted Verilog in Icarus. No synthesis, utilization, timing, route, or physical hardware claim follows from those tests.

Re-exports§

pub use permutation::keccak_f1600;
pub use round::keccak_round;
pub use round::keccak_round_00;
pub use round::keccak_round_01;
pub use round::keccak_round_02;
pub use round::keccak_round_03;
pub use round::keccak_round_04;
pub use round::keccak_round_05;
pub use round::keccak_round_06;
pub use round::keccak_round_07;
pub use round::keccak_round_08;
pub use round::keccak_round_09;
pub use round::keccak_round_10;
pub use round::keccak_round_11;
pub use round::keccak_round_12;
pub use round::keccak_round_13;
pub use round::keccak_round_14;
pub use round::keccak_round_15;
pub use round::keccak_round_16;
pub use round::keccak_round_17;
pub use round::keccak_round_18;
pub use round::keccak_round_19;
pub use round::keccak_round_20;
pub use round::keccak_round_21;
pub use round::keccak_round_22;
pub use round::keccak_round_23;
pub use sponge::absorb_rate_block;
pub use sponge::xor_rate_block;

Structs§

IterativeInput: Request presented to IterativeKeccak.
IterativeKeccak: A synthesizable Keccak-f[1600] engine that reuses one round cell.
IterativeOutput: Status and result produced by IterativeKeccak.
LegacyKeccak256: Host-side legacy Keccak-256 sponge and block-packing model.
RateBlock: One 1,088-bit Keccak-256 absorption block.

Constants§

LEGACY_DOMAIN_BYTE: Domain byte used by legacy Keccak padding.
RATE_BYTES: Keccak-256’s byte rate (1600 - 2*256 bits).
RATE_LANES: Keccak-256’s rate expressed as 64-bit lanes.
ROTATION_OFFSETS: Keccak-f[1600] Rho offsets indexed as [x][y].
ROUND_CONSTANTS: The 24 Keccak-f[1600] Iota constants, in round order.
ROUND_COUNT: Number of rounds in Keccak-f[1600].

Functions§

absorb_rate_block: XOR one complete rate block into a state and permute it.
digest_from_state: Extract the first 256 rate bits as a Keccak digest.
generate_iterative_verilog: Generate the 24-cycle iterative engine and its RHDL-owned storage modules.
generate_permutation_verilog: Generate a standalone 24-round combinational permutation module.
generate_round_verilog: Generate a standalone combinational one-round Verilog module.
keccak_f1600: Apply all 24 Keccak-f[1600] rounds as one combinational RHDL kernel.
keccak_round: Apply one Keccak-f[1600] round selected at runtime.
keccak_round_00: Apply compile-time Keccak-f[1600] round 0.
keccak_round_01: Apply compile-time Keccak-f[1600] round 1.
keccak_round_02: Apply compile-time Keccak-f[1600] round 2.
keccak_round_03: Apply compile-time Keccak-f[1600] round 3.
keccak_round_04: Apply compile-time Keccak-f[1600] round 4.
keccak_round_05: Apply compile-time Keccak-f[1600] round 5.
keccak_round_06: Apply compile-time Keccak-f[1600] round 6.
keccak_round_07: Apply compile-time Keccak-f[1600] round 7.
keccak_round_08: Apply compile-time Keccak-f[1600] round 8.
keccak_round_09: Apply compile-time Keccak-f[1600] round 9.
keccak_round_10: Apply compile-time Keccak-f[1600] round 10.
keccak_round_11: Apply compile-time Keccak-f[1600] round 11.
keccak_round_12: Apply compile-time Keccak-f[1600] round 12.
keccak_round_13: Apply compile-time Keccak-f[1600] round 13.
keccak_round_14: Apply compile-time Keccak-f[1600] round 14.
keccak_round_15: Apply compile-time Keccak-f[1600] round 15.
keccak_round_16: Apply compile-time Keccak-f[1600] round 16.
keccak_round_17: Apply compile-time Keccak-f[1600] round 17.
keccak_round_18: Apply compile-time Keccak-f[1600] round 18.
keccak_round_19: Apply compile-time Keccak-f[1600] round 19.
keccak_round_20: Apply compile-time Keccak-f[1600] round 20.
keccak_round_21: Apply compile-time Keccak-f[1600] round 21.
keccak_round_22: Apply compile-time Keccak-f[1600] round 22.
keccak_round_23: Apply compile-time Keccak-f[1600] round 23.
software_keccak_f1600: Independent native-Rust Keccak-f[1600] permutation.
software_keccak_round: Independent native-Rust implementation of one Keccak-f[1600] round.
xor_rate_block: XOR one complete rate block into the 17 rate lanes of a state.

Type Aliases§

Digest: A 256-bit Keccak digest in byte order.
KeccakState: A Keccak-f[1600] state in the canonical x + 5*y lane order.