Struct Sha256FillerHelper 

pub struct Sha256FillerHelper {
    pub row_idx_encoder: Encoder,
}

A helper struct for the SHA256 trace generation. Also, separates the inner AIR from the trace generation.

Fields

row_idx_encoder: Encoder

Implementations

impl Sha256FillerHelper

The trace generation of SHA256 should be done in two passes. The first pass should do get_block_trace for every block and generate the invalid rows through get_default_row The second pass should go through all the blocks and call generate_missing_cells

pub fn new() -> Self

pub fn get_block_hash(prev_hash: &[u32; 8], input: [u8; 64]) -> [u32; 8]

This function takes the input_message (padding not handled), the previous hash, and returns the new hash after processing the block input

pub fn generate_block_trace<F: PrimeField32>( &self, trace: &mut [F], trace_width: usize, trace_start_col: usize, input: &[u32; 16], bitwise_lookup_chip: &BitwiseOperationLookupChip<8>, prev_hash: &[u32; 8], is_last_block: bool, global_block_idx: u32, local_block_idx: u32, )

This function takes a 512-bit chunk of the input message (padding not handled), the previous hash, a flag indicating if it’s the last block, the global block index, the local block index, and the buffer values that will be put in rows 0..4. Will populate the given trace with the trace of the block, where the width of the trace is trace_width and the starting column for the Sha256Air is trace_start_col. Note: this function only generates some of the required trace. Another pass is required, refer to Self::generate_missing_cells for details.

pub fn generate_missing_cells<F: PrimeField32>( &self, trace: &mut [F], trace_width: usize, trace_start_col: usize, )

This function will fill in the cells that we couldn’t do during the first pass. This function should be called only after generate_block_trace was called for all blocks And Self::generate_default_row is called for all invalid rows Will populate the missing values of trace, where the width of the trace is trace_width and the starting column for the Sha256Air is trace_start_col. Note: trace needs to be the rows 1..17 of a block and the first row of the next block

pub fn generate_default_row<F: PrimeField32>( self: &Sha256FillerHelper, cols: &mut Sha256RoundCols<F>, )

Fills the cols as a padding row Note: we still need to correctly fill in the hash values, carries and intermeds

Trait Implementations

impl Default for Sha256FillerHelper

fn default() -> Self

Returns the “default value” for a type.