Module hasher 

Hasher chiplet trace constants and types.

This module defines the structure of the hasher chiplet’s execution trace, including:

• Trace selectors that determine which hash operation is being performed
• State layout for the Poseidon2 permutation (12 field elements: 8 rate + 4 capacity)
• Column ranges and indices for accessing trace data

The hasher chiplet supports several operations:

• Linear hashing (absorbing arbitrary-length inputs)
• 2-to-1 hashing (Merkle tree node computation)
• Merkle path verification
• Merkle root updates (for authenticated data structure modifications)

Structs

Hasher

Implementation of the Poseidon2 hash function with 256-bit output.

Word

A unit of data consisting of 4 field elements.

Constants

CAPACITY_COL_RANGE

The capacity portion of the hasher state in the execution trace, located in columns 11..15. With LE sponge state layout [RATE0, RATE1, CAP], capacity comes last.

CAPACITY_DOMAIN_IDX

The index in the hasher state where the domain is set when initializing the hasher.

CAPACITY_LEN

Number of field elements in the capacity portion of the hasher’s state.

DIGEST_LEN

DIGEST_RANGE

The output portion of the hash state, located in the first rate word (RATE0).

HASH_CYCLE_LEN

The number of rows in the execution trace required to compute a permutation of Poseidon2. This is equal to 32.

HASH_CYCLE_LEN_FELT

LAST_CYCLE_ROW

Index of the last row in a permutation cycle (0-based).

LAST_CYCLE_ROW_FELT

LINEAR_HASH

Specifies a start of a new linear hash computation or absorption of new elements into an executing linear hash computation. These selectors can also be used for a simple 2-to-1 hash computation.

LINEAR_HASH_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 1, 0, 0], flag = rev(selector) + 1 = [0, 0, 1 | 0] + 1 = 3

MP_VERIFY

Specifies a start of Merkle path verification computation or absorption of a new path node into the hasher state.

MP_VERIFY_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 1, 0, 1], flag = rev(selector) + 1 = [1, 0, 1 | 0] + 1 = 11

MR_UPDATE_NEW

Specifies a start of Merkle path verification or absorption of a new path node into the hasher state for the “new” node value during Merkle root update computation.

MR_UPDATE_NEW_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 1, 1, 1], flag = rev(selector) + 1 = [1, 1, 1 | 0] + 1 = 15

MR_UPDATE_OLD

Specifies a start of Merkle path verification or absorption of a new path node into the hasher state for the “old” node value during Merkle root update computation.

MR_UPDATE_OLD_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 1, 1, 0], flag = rev(selector) + 1 = [0, 1, 1 | 0] + 1 = 7

NUM_ROUNDS

Number of round steps used to complete a single permutation.

NUM_SELECTORS

Number of selector columns in the trace.

P1_COL_IDX

Index of the auxiliary trace column tracking the state of the sibling table.

RATE_COL_RANGE

The rate portion of the hasher state in the execution trace, located in columns 3..11. With LE sponge state layout [RATE0, RATE1, CAP], rate comes first.

RATE_LEN

Number of field elements in the rate portion of the hasher’s state.

RETURN_HASH

Specifies a completion of a computation such that only the hash result (values in h0, h1, h2 h3) is returned.

RETURN_HASH_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 0, 0, 0], flag = rev(selector) + 1 = [0, 0, 0 | 0] + 1 = 1

RETURN_STATE

Specifies a completion of a computation such that the entire hasher state (values in h0 through h11) is returned.

RETURN_STATE_LABEL

Unique label computed as 1 plus the full chiplet selector with the bits reversed. selector = [0 | 0, 0, 1], flag = rev(selector) + 1 = [1, 0, 0 | 0] + 1 = 9

STATE_COL_RANGE

The hasher state portion of the execution trace, located in columns 3..15.

STATE_WIDTH

Number of field element needed to represent the sponge state for the hash function.

TRACE_WIDTH

Number of columns in Hasher execution trace. There is one additional column for the node index.

Type Aliases

HasherState

Type for the Hasher’s state.

Selectors

Type for Hasher trace selector. These selectors are used to define which transition function is to be applied at a specific row of the hasher execution trace.