Trait Params 

pub trait Params: Clone + Default {
    type Hash: TweakableHash;

    const N: usize;
    const H: usize;
    const D: usize;
    const H_PRIME: usize;
    const A: usize;
    const K: usize;
    const M: usize;
    const NAME: &'static str;
    const LG_W: usize = 4;
    const W: usize = 16;
    const LEN1: usize = _;
    const LEN2: usize = 3;
    const LEN: usize = _;
    const PK_LEN: usize = _;
    const SK_LEN: usize = _;
}

Trait defining all compile-time parameters for an SLH-DSA instance.

Implementors of this trait represent a specific FIPS 205 parameter set (e.g., SLH-DSA-SHAKE-128f). The constants fully determine key sizes, signature sizes, tree structures, and hash output lengths; the Hash associated type selects the tweakable-hash instantiation (SHAKE or SHA-2).

See FIPS 205, Table 2 for the complete list of parameter values.

Required Associated Constants

const N: usize

Security parameter n: hash output length in bytes.

This is the fundamental security parameter. All hash outputs, secret values, and tree nodes are n bytes long.

const H: usize

Total hypertree height: h = d * h'.

Determines the total number of FORS key pairs the scheme can use: 2^h.

const D: usize

Number of layers d in the hypertree.

The hypertree consists of d stacked XMSS trees, each of height h'.

const H_PRIME: usize

Height h' of each individual XMSS tree within the hypertree.

Each XMSS tree authenticates 2^h' keys in the layer below it.

const A: usize

Height a of each FORS tree (each tree has 2^a leaves).

const K: usize

Number k of FORS trees used per signature.

const M: usize

Message digest length m in bytes, output by H_msg.

The digest is split into FORS indices, a tree index, and a leaf index.

const NAME: &'static str

Human-readable name of this parameter set (e.g., "SLH-DSA-SHAKE-128f").

Provided Associated Constants

const LG_W: usize = 4

Winternitz parameter lg(w), always 4 for the FIPS 205 parameter sets.

const W: usize = 16

Winternitz parameter w = 2^lg_w = 16.

Controls the time/size trade-off in WOTS+ chains: each chain has w - 1 steps.

const LEN1: usize = _

WOTS+ parameter len1 = ceil(8*n / lg_w) = 2*n (since lg_w = 4).

Number of base-w digits needed to represent an n-byte message.

const LEN2: usize = 3

WOTS+ parameter len2 = 3 for all FIPS 205 parameter sets.

Number of base-w digits in the checksum.

const LEN: usize = _

WOTS+ parameter len = len1 + len2: total number of hash chains.

const PK_LEN: usize = _

Public key size in bytes: 2*n (PK.seed || PK.root).

const SK_LEN: usize = _

Secret key size in bytes: 4*n (SK.seed || SK.prf || PK.seed || PK.root).

Required Associated Types

type Hash: TweakableHash

Tweakable-hash family for this parameter set: ShakeFamily (FIPS 205 §11.1) or Sha2Family (§11.2).

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Params for Sha2_128f

const N: usize = 16

const H: usize = 66

const D: usize = 22

const H_PRIME: usize = 3

const A: usize = 6

const K: usize = 33

const M: usize = 34

const NAME: &'static str = "SLH-DSA-SHA2-128f"

type Hash = Sha2Family

impl Params for Sha2_128s

const N: usize = 16

const H: usize = 63

const D: usize = 7

const H_PRIME: usize = 9

const A: usize = 12

const K: usize = 14

const M: usize = 30

const NAME: &'static str = "SLH-DSA-SHA2-128s"

type Hash = Sha2Family

impl Params for Sha2_192f

const N: usize = 24

const H: usize = 66

const D: usize = 22

const H_PRIME: usize = 3

const A: usize = 8

const K: usize = 33

const M: usize = 42

const NAME: &'static str = "SLH-DSA-SHA2-192f"

type Hash = Sha2Family

impl Params for Sha2_192s

const N: usize = 24

const H: usize = 63

const D: usize = 7

const H_PRIME: usize = 9

const A: usize = 14

const K: usize = 17

const M: usize = 39

const NAME: &'static str = "SLH-DSA-SHA2-192s"

type Hash = Sha2Family

impl Params for Sha2_256f

const N: usize = 32

const H: usize = 68

const D: usize = 17

const H_PRIME: usize = 4

const A: usize = 9

const K: usize = 35

const M: usize = 49

const NAME: &'static str = "SLH-DSA-SHA2-256f"

type Hash = Sha2Family

impl Params for Sha2_256s

const N: usize = 32

const H: usize = 64

const D: usize = 8

const H_PRIME: usize = 8

const A: usize = 14

const K: usize = 22

const M: usize = 47

const NAME: &'static str = "SLH-DSA-SHA2-256s"

type Hash = Sha2Family

impl Params for Shake128f

const N: usize = 16

const H: usize = 66

const D: usize = 22

const H_PRIME: usize = 3

const A: usize = 6

const K: usize = 33

const M: usize = 34

const NAME: &'static str = "SLH-DSA-SHAKE-128f"

type Hash = ShakeFamily

impl Params for Shake128s

const N: usize = 16

const H: usize = 63

const D: usize = 7

const H_PRIME: usize = 9

const A: usize = 12

const K: usize = 14

const M: usize = 30

const NAME: &'static str = "SLH-DSA-SHAKE-128s"

type Hash = ShakeFamily

impl Params for Shake192f

const N: usize = 24

const H: usize = 66

const D: usize = 22

const H_PRIME: usize = 3

const A: usize = 8

const K: usize = 33

const M: usize = 42

const NAME: &'static str = "SLH-DSA-SHAKE-192f"

type Hash = ShakeFamily

impl Params for Shake192s

const N: usize = 24

const H: usize = 63

const D: usize = 7

const H_PRIME: usize = 9

const A: usize = 14

const K: usize = 17

const M: usize = 39

const NAME: &'static str = "SLH-DSA-SHAKE-192s"

type Hash = ShakeFamily

impl Params for Shake256f

const N: usize = 32

const H: usize = 68

const D: usize = 17

const H_PRIME: usize = 4

const A: usize = 9

const K: usize = 35

const M: usize = 49

const NAME: &'static str = "SLH-DSA-SHAKE-256f"

type Hash = ShakeFamily

impl Params for Shake256s

const N: usize = 32

const H: usize = 64

const D: usize = 8

const H_PRIME: usize = 8

const A: usize = 14

const K: usize = 22

const M: usize = 47

const NAME: &'static str = "SLH-DSA-SHAKE-256s"

type Hash = ShakeFamily