Crate cyber_hemera 

Poseidon2 hash over the Goldilocks field (Hemera parameters).

This crate provides a streaming hash API backed by the Poseidon2 algebraic hash function operating over the Goldilocks prime field (p = 2^64 - 2^32 + 1).

Hemera Parameters

• Field: Goldilocks (p = 2^64 - 2^32 + 1)
• State width: t = 16
• Full rounds: R_F = 8
• Partial rounds: R_P = 64
• S-box degree: d = 7 (x^7)
• Rate: 8 elements (56 input bytes per block)
• Capacity: 8 elements
• Output: 8 elements (64 bytes)
• Padding: 0x01 || 0x00*
• Encoding: little-endian canonical

Examples

use hemera::{hash, derive_key};

let digest = hash(b"hello world");
println!("{digest}");

let key = derive_key("my app v1", b"key material");

Modules

hazmat

Low-level primitives for BAO-style Merkle tree construction.

Structs

Hash

A 64-byte Poseidon2 hash output (Hemera: 8 Goldilocks elements).

Hasher

A streaming Poseidon2 hasher.

OutputReader

An extendable-output reader that can produce arbitrary-length output.

Constants

CAPACITY

Number of capacity elements in the sponge.

COLLISION_BITS

Classical collision resistance in bits.

OUTPUT_BYTES

Number of output bytes per squeeze (8 elements × 8 bytes).

OUTPUT_ELEMENTS

Number of output elements extracted per squeeze (= rate).

RATE

Number of rate elements in the sponge.

RATE_BYTES

Number of input bytes that fill one rate block (8 elements × 7 bytes).

ROUNDS_F

Number of full (external) rounds — 4 initial + 4 final.

ROUNDS_P

Number of partial (internal) rounds.

SBOX_DEGREE

S-box degree (x → x^d).

WIDTH

Width of the Poseidon2 state (number of Goldilocks field elements).

Functions

derive_key

Derive a key from a context string and key material.

hash

Hash the input bytes and return a 64-byte digest.

keyed_hash

Hash the input bytes with a key.