primitives.transcript

Fiat-Shamir transcript using Poseidon2 sponge.

Attributes

SpongeState
Hash
Challenge
HASH_SIZE

Classes

Transcript

Fiat-Shamir transcript using Poseidon2 sponge construction.

Module Contents

primitives.transcript.SpongeState

primitives.transcript.Hash

primitives.transcript.Challenge

primitives.transcript.HASH_SIZE = 4

class primitives.transcript.Transcript(arity: int = 4, custom: bool = False)

Fiat-Shamir transcript using Poseidon2 sponge construction.

arity = 4

transcript_state_size = 4

transcript_pending_size = 12

transcript_out_size = 16

sponge_width = 16

state: SpongeState = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

pending: list[int] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

out: list[int] = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

pending_cursor = 0

out_cursor = 0

put(elements: list[int] | list) → None

Absorb field elements into the sponge.

get_field() → Challenge

Squeeze 3 field elements as a cubic extension challenge.

get_state(n_outputs: int = None) → SpongeState

Get current sponge state (for grinding challenge).

get_permutations(n: int, n_bits: int) → list[int]

Generate n pseudorandom indices, each using n_bits bits.

set_state(state: list[int], out: list[int], out_cursor: int, pending_cursor: int, pending: list[int] = None) → None

Restore transcript state from captured values.

Used to replay Fiat-Shamir transcript from a known state, enabling deterministic proof generation matching C++ output.

Args:

state: Sponge state (16 elements) out: Output buffer (16 elements) out_cursor: Position in output buffer pending_cursor: Position in pending buffer pending: Pending buffer contents (optional, defaults to zeros)