Module encode 

Encoding and decoding of keys, signatures, and polynomials. Encoding and decoding algorithms for ML-DSA (FIPS 204, Algorithms 9-28).

Provides bit-level packing and unpacking of polynomials and polynomial vectors into compact byte representations, as well as the Power2Round decomposition used during key generation.

All vector functions accept slices (&[[i32; N]]) instead of &Vec<...> to avoid requiring heap-allocated containers.

Stability (hazmat tier)

This module is part of the hazmat expert building-block layer: it is public only with the hazmat Cargo feature, for KAT/test-vector tooling and research. Read each function’s invariants before use. No stability, misuse-resistance, or side-channel promise applies to this tier — its API may change in any release. The typed facade is the guaranteed API.

Functions

bit_pack

Pack a polynomial whose coefficients lie in [-a, b].

bit_unpack

Unpack a polynomial whose coefficients lie in [-a, b].

hint_bit_pack

Pack a hint vector into bytes.

hint_bit_unpack

Unpack a hint vector from bytes.

pk_decode

Decode a public key from bytes.

pk_encode

Encode a public key as bytes.

power2round

Decompose a coefficient into high and low parts using a power-of-2 divisor.

power2round_vec

Apply power2round to every coefficient of a polynomial vector.

sig_decode

Decode a signature from bytes.

sig_encode

Encode a signature as bytes.

simple_bit_pack

Pack a polynomial whose coefficients lie in [0, b].

simple_bit_unpack

Unpack a polynomial whose coefficients lie in [0, b].

sk_decode

Decode a secret key from bytes.

sk_decode_s1

Decode a single polynomial of s1 from the packed secret key.

sk_decode_s2

Decode a single polynomial of s2 from the packed secret key.

sk_decode_seeds

Decode only the seeds (rho, K, tr) from a secret key, without unpacking any polynomial. Returns 128 bytes of stack.

sk_decode_t0

Decode a single polynomial of t0 from the packed secret key.

sk_encode

Encode a secret key as bytes.

w1_encode

Encode the high-order bits vector w1 as bytes.

Type Aliases

DecodedSecretKey

Decoded ML-DSA secret-key components (rho, K, tr, s1, s2, t0) (FIPS 204 skDecode).

DecodedSignature

Decoded ML-DSA signature components (c_tilde, z, h) (FIPS 204 sigDecode).