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chip::mul_fixed: Refactor mul_fixed::Config. 

This commit does not introduce circuit changes.
This commit is contained in:
therealyingtong 2021-12-03 11:51:59 -05:00 committed by Jack Grigg
parent a7dad1d611
commit 1a7e832ed4
5 changed files with 72 additions and 57 deletions
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37
src/circuit/gadget/ecc/chip.rs
View File

@ -133,11 +133,6 @@ pub struct EccConfig {
/// Advice columns needed by instructions in the ECC chip.
pub advices: [Column<Advice>; 10],
/// Coefficients of interpolation polynomials for x-coordinates (used in fixed-base scalar multiplication)
pub lagrange_coeffs: [Column<Fixed>; constants::H],
/// Fixed z such that y + z = u^2 some square, and -y + z is a non-square. (Used in fixed-base scalar multiplication)
pub fixed_z: Column<Fixed>,
/// Incomplete addition
add_incomplete: add_incomplete::Config,
@ -147,6 +142,9 @@ pub struct EccConfig {
/// Variable-base scalar multiplication
mul: mul::Config,
/// TODO: Remove this.
pub mul_fixed: mul_fixed::Config,
/// Fixed-base full-width scalar multiplication
pub q_mul_fixed_full: Selector,
/// Fixed-base signed short scalar multiplication
@ -206,10 +204,6 @@ impl EccChip {
) -> <Self as Chip<pallas::Base>>::Config {
// The following columns need to be equality-enabled for their use in sub-configs:
//
// mul_fixed::Config:
// - advices[4]: window
// - advices[5]: u
//
// mul_fixed::base_field_element::Config:
// - [advices[6], advices[7], advices[8]]: canon_advices
//
@ -238,13 +232,26 @@ impl EccChip {
// Create variable-base scalar mul gates
let mul = mul::Config::configure(meta, add, range_check, advices);
// Create config that is shared across short, base-field, and full-width
// fixed-base scalar mul.
let mul_fixed = mul_fixed::Config::configure(
meta,
q_mul_fixed_running_sum,
lagrange_coeffs,
advices[4],
advices[0],
advices[1],
advices[5],
add,
add_incomplete,
);
let config = EccConfig {
advices,
lagrange_coeffs,
fixed_z: meta.fixed_column(),
add_incomplete,
add,
mul,
mul_fixed,
q_mul_fixed_full: meta.selector(),
q_mul_fixed_short: meta.selector(),
q_mul_fixed_base_field: meta.selector(),
@ -254,14 +261,6 @@ impl EccChip {
running_sum_config,
};
// Create gate that is used both in fixed-base mul using a short signed exponent,
// and fixed-base mul using a base field element.
{
// The const generic does not matter when creating gates.
let mul_fixed_config: mul_fixed::Config<{ constants::NUM_WINDOWS }> = (&config).into();
mul_fixed_config.running_sum_coords_gate(meta);
}
// Create gate that is only used in full-width fixed-base scalar mul.
{
let mul_fixed_full_config: mul_fixed::full_width::Config = (&config).into();

60
src/circuit/gadget/ecc/chip/mul_fixed.rs
View File

@ -1,6 +1,6 @@
use super::{
add, add_incomplete, CellValue, EccBaseFieldElemFixed, EccConfig, EccScalarFixed,
EccScalarFixedShort, NonIdentityEccPoint, Var,
add, add_incomplete, CellValue, EccBaseFieldElemFixed, EccScalarFixed, EccScalarFixedShort,
NonIdentityEccPoint, Var,
};
use crate::constants::{
self,
@ -75,8 +75,8 @@ impl OrchardFixedBases {
}
}
#[derive(Clone, Debug)]
pub struct Config<const NUM_WINDOWS: usize> {
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct Config {
q_mul_fixed_running_sum: Selector,
// The fixed Lagrange interpolation coefficients for `x_p`.
lagrange_coeffs: [Column<Fixed>; constants::H],
@ -97,18 +97,32 @@ pub struct Config<const NUM_WINDOWS: usize> {
add_incomplete_config: add_incomplete::Config,
}
impl<const NUM_WINDOWS: usize> From<&EccConfig> for Config<NUM_WINDOWS> {
fn from(ecc_config: &EccConfig) -> Self {
impl Config {
#[allow(clippy::too_many_arguments)]
pub(super) fn configure(
meta: &mut ConstraintSystem<pallas::Base>,
q_mul_fixed_running_sum: Selector,
lagrange_coeffs: [Column<Fixed>; constants::H],
window: Column<Advice>,
x_p: Column<Advice>,
y_p: Column<Advice>,
u: Column<Advice>,
add_config: add::Config,
add_incomplete_config: add_incomplete::Config,
) -> Self {
meta.enable_equality(window.into());
meta.enable_equality(u.into());
let config = Self {
q_mul_fixed_running_sum: ecc_config.q_mul_fixed_running_sum,
lagrange_coeffs: ecc_config.lagrange_coeffs,
fixed_z: ecc_config.fixed_z,
x_p: ecc_config.advices[0],
y_p: ecc_config.advices[1],
window: ecc_config.advices[4],
u: ecc_config.advices[5],
add_config: ecc_config.add,
add_incomplete_config: ecc_config.add_incomplete,
q_mul_fixed_running_sum,
lagrange_coeffs,
fixed_z: meta.fixed_column(),
window,
x_p,
y_p,
u,
add_config,
add_incomplete_config,
};
// Check relationships between this config and `add_config`.
@ -141,11 +155,11 @@ impl<const NUM_WINDOWS: usize> From<&EccConfig> for Config<NUM_WINDOWS> {
);
}
config.running_sum_coords_gate(meta);
config
}
}
impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
/// Check that each window in the running sum decomposition uses the correct y_p
/// and interpolated x_p.
///
@ -155,7 +169,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
/// This gate is not used in the mul_fixed::full_width helper, since the full-width
/// scalar is witnessed directly as three-bit windows instead of being decomposed
/// via a running sum.
pub(crate) fn running_sum_coords_gate(&self, meta: &mut ConstraintSystem<pallas::Base>) {
fn running_sum_coords_gate(&self, meta: &mut ConstraintSystem<pallas::Base>) {
meta.create_gate("Running sum coordinates check", |meta| {
let q_mul_fixed_running_sum = meta.query_selector(self.q_mul_fixed_running_sum);
@ -213,7 +227,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
}
#[allow(clippy::type_complexity)]
fn assign_region_inner(
fn assign_region_inner<const NUM_WINDOWS: usize>(
&self,
region: &mut Region<'_, pallas::Base>,
offset: usize,
@ -222,7 +236,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
coords_check_toggle: Selector,
) -> Result<(NonIdentityEccPoint, NonIdentityEccPoint), Error> {
// Assign fixed columns for given fixed base
self.assign_fixed_constants(region, offset, base, coords_check_toggle)?;
self.assign_fixed_constants::<NUM_WINDOWS>(region, offset, base, coords_check_toggle)?;
// Initialize accumulator
let acc = self.initialize_accumulator(region, offset, base, scalar)?;
@ -231,12 +245,12 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
let acc = self.add_incomplete(region, offset, acc, base, scalar)?;
// Process most significant window using complete addition
let mul_b = self.process_msb(region, offset, base, scalar)?;
let mul_b = self.process_msb::<NUM_WINDOWS>(region, offset, base, scalar)?;
Ok((acc, mul_b))
}
fn assign_fixed_constants(
fn assign_fixed_constants<const NUM_WINDOWS: usize>(
&self,
region: &mut Region<'_, pallas::Base>,
offset: usize,
@ -411,7 +425,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
Ok(acc)
}
fn process_msb(
fn process_msb<const NUM_WINDOWS: usize>(
&self,
region: &mut Region<'_, pallas::Base>,
offset: usize,

20
src/circuit/gadget/ecc/chip/mul_fixed/base_field_elem.rs
View File

@ -24,7 +24,7 @@ pub struct Config {
canon_advices: [Column<Advice>; 3],
lookup_config: LookupRangeCheckConfig<pallas::Base, { sinsemilla::K }>,
running_sum_config: RunningSumConfig<pallas::Base, { constants::FIXED_BASE_WINDOW_SIZE }>,
super_config: super::Config<{ constants::NUM_WINDOWS }>,
super_config: super::Config,
}
impl From<&EccConfig> for Config {
@ -35,7 +35,7 @@ impl From<&EccConfig> for Config {
canon_advices: [config.advices[6], config.advices[7], config.advices[8]],
lookup_config: config.lookup_config,
running_sum_config: config.running_sum_config.clone(),
super_config: config.into(),
super_config: config.mul_fixed,
};
let add_incomplete_advices = config.super_config.add_incomplete_config.advice_columns();
@ -180,13 +180,15 @@ impl Config {
}
};
let (acc, mul_b) = self.super_config.assign_region_inner(
&mut region,
offset,
&(&scalar).into(),
base.into(),
self.q_mul_fixed_running_sum,
)?;
let (acc, mul_b) = self
.super_config
.assign_region_inner::<{ constants::NUM_WINDOWS }>(
&mut region,
offset,
&(&scalar).into(),
base.into(),
self.q_mul_fixed_running_sum,
)?;
Ok((scalar, acc, mul_b))
},

6
src/circuit/gadget/ecc/chip/mul_fixed/full_width.rs
View File

@ -14,14 +14,14 @@ use pasta_curves::{arithmetic::FieldExt, pallas};
pub struct Config {
q_mul_fixed_full: Selector,
super_config: super::Config<NUM_WINDOWS>,
super_config: super::Config,
}
impl From<&EccConfig> for Config {
fn from(config: &EccConfig) -> Self {
Self {
q_mul_fixed_full: config.q_mul_fixed_full,
super_config: config.into(),
super_config: config.mul_fixed,
}
}
}
@ -124,7 +124,7 @@ impl Config {
let scalar = self.witness(&mut region, offset, scalar)?;
let (acc, mul_b) = self.super_config.assign_region_inner(
let (acc, mul_b) = self.super_config.assign_region_inner::<NUM_WINDOWS>(
&mut region,
offset,
&(&scalar).into(),

6
src/circuit/gadget/ecc/chip/mul_fixed/short.rs
View File

@ -21,7 +21,7 @@ pub struct Config {
q_mul_fixed_short: Selector,
q_mul_fixed_running_sum: Selector,
running_sum_config: RunningSumConfig<pallas::Base, { FIXED_BASE_WINDOW_SIZE }>,
super_config: super::Config<NUM_WINDOWS_SHORT>,
super_config: super::Config,
}
impl From<&EccConfig> for Config {
@ -30,7 +30,7 @@ impl From<&EccConfig> for Config {
q_mul_fixed_short: config.q_mul_fixed_short,
q_mul_fixed_running_sum: config.q_mul_fixed_running_sum,
running_sum_config: config.running_sum_config.clone(),
super_config: config.into(),
super_config: config.mul_fixed,
}
}
}
@ -110,7 +110,7 @@ impl Config {
// Decompose the scalar
let scalar = self.decompose(&mut region, offset, magnitude_sign)?;
let (acc, mul_b) = self.super_config.assign_region_inner(
let (acc, mul_b) = self.super_config.assign_region_inner::<NUM_WINDOWS_SHORT>(
&mut region,
offset,
&(&scalar).into(),