primitives.poseidon2

Poseidon2 hash over BabyBear via Rust FFI.

Wraps Plonky3’s production Poseidon2BabyBear<16> permutation.

Reference:

p3-symmetric (PaddingFreeSponge, TruncatedPermutation).

Functions

permute(→ list[int])	Apply Poseidon2 permutation to width-16 state.
compress(→ list[int])	Compress two 8-element digests into one.
compress_batch(→ list[list[int]])	Batch compress N pairs of 8-element digests in parallel via rayon.
hash_batch(→ list[list[int]])	Batch hash N variable-length inputs to 8-element digests in parallel via rayon.
hash_to_digest(→ list[int])	Hash variable-length input to 8-element digest.

Module Contents

primitives.poseidon2.permute(state: list[int]) → list[int]

Apply Poseidon2 permutation to width-16 state.

Args:

state: 16 BabyBear field elements.

Returns:

Permuted 16-element state.

primitives.poseidon2.compress(left: list[int], right: list[int]) → list[int]

Compress two 8-element digests into one.

TruncatedPermutation: concatenate inputs, permute, truncate to DIGEST_SIZE.

Args:

left: First 8-element digest. right: Second 8-element digest.

Returns:

8-element compressed digest.

Reference:

p3-symmetric TruncatedPermutation<Perm, 2, 8, 16>

primitives.poseidon2.compress_batch(lefts: list[list[int]], rights: list[list[int]]) → list[list[int]]

Batch compress N pairs of 8-element digests in parallel via rayon.

Args:

lefts: N left digests (each 8 elements). rights: N right digests (each 8 elements).

Returns:

N compressed 8-element digests.

primitives.poseidon2.hash_batch(inputs: list[list[int]]) → list[list[int]]

Batch hash N variable-length inputs to 8-element digests in parallel via rayon.

Each input is hashed via PaddingFreeSponge (same as hash_to_digest).

Args:

inputs: N variable-length lists of BabyBear field elements.

Returns:

N 8-element digests.

primitives.poseidon2.hash_to_digest(inputs: list[int]) → list[int]

Hash variable-length input to 8-element digest.

PaddingFreeSponge: overwrite rate portion, permute, repeat.

Args:

inputs: Variable-length list of BabyBear field elements.

Returns:

8-element digest.

Reference:

p3-symmetric PaddingFreeSponge<Perm, 16, 8, 8>