Module interpreter

Constants

LIMB_BITSIZE_LARGE

In FEC addition we use bigger limbs, of 75 bits, that are still nicely decomposable into smaller 15bit ones for range checking.

LIMB_BITSIZE_SMALL

Alias for LIMB_BITSIZE, used for convenience.

N_LIMBS_LARGE

N_LIMBS_SMALL

Alias for N_LIMBS, used for convenience.

Traits

HybridSerHelpers

Functions

bigint_to_biguint_f

Interprets bigint input as an element of a field modulo f_bi, converts it to [0,f_bi) range, and outptus a corresponding biguint representation.

build_selectors

Builds fixed selectors for serialization circuit.

combine_carry

Helper function for limb recombination for carry specifically. Each big carry limb is stored as 6 (not 5!) small elements. We accept 36 small limbs, and return 6 large ones.

combine_limbs_m_to_n

Helper function for limb recombination.

combine_small_to_large

Helper function for limb recombination.

constrain_multiplication

This constarins the multiplication part of the circuit.

deserialize_field_element

Deserialize a field element of the scalar field of Vesta or Pallas given as a sequence of 3 limbs of 88 bits. It will deserialize into limbs of 15 bits. Given a scalar field element of Vesta or Pallas, here the decomposition:

ff_modulus_highest_limb

Returns the highest limb of the foreign field modulus. Is used by the lookups.

fold_choice2

A convenience helper: given a list_len and n (arguments of choice2), it creates an array consisting of f(i,j) where i,j \in [0,list_len] such that i + j = n, and then sums all the elements in this array.

limb_decompose_biguint

Decompose biguint into N limbs of bit size B.

limb_decompose_ff

Decomposes a foreign field element into N limbs of bit size B.

multiplication_circuit

Multiplication sub-circuit of the serialization/bootstrap procedure. Takes challenge x_{log i} and coefficient c_prev_i as input, returns next coefficient c_i.

serialization_circuit

Full serialization circuit.