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Adapt to new types introduced in fiat-crypto 0.2
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@divergentdave
divergentdave committed Sep 2, 2023
1 parent 04f42e4 commit 3a0f361
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Showing 3 changed files with 78 additions and 71 deletions.
2 changes: 1 addition & 1 deletion Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ exclude = [".gitignore", ".github/*"]
[dependencies]
subtle = "2.2.2"
rand_core = { version = "0.6", optional = true }
fiat-crypto = { version = "0.1.4", optional = true }
fiat-crypto = { version = "0.2.0", optional = true }

[dependencies.zeroize]
version = "1"
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73 changes: 39 additions & 34 deletions src/field/fiat_u64/constants.rs
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Original file line number Diff line number Diff line change
@@ -1,23 +1,26 @@
use fiat_crypto::p448_solinas_64::fiat_p448_tight_field_element;

// Move all curve specific constants into this file
// as they will have different representations depending on the backend
use crate::curve::edwards::ExtendedPoint;
use crate::curve::twedwards::extended::ExtendedPoint as TwExtendedPoint;
use crate::field::fiat_u64::FieldElement56;

/// -4 * Twisted_D = -4 * (EDWARDS_D-1)
pub const NEG_FOUR_TIMES_TWISTED_D: FieldElement56 = FieldElement56([
156327,
0,
0,
0,
72057594037927935,
72057594037927935,
72057594037927935,
72057594037927935,
]);
pub const NEG_FOUR_TIMES_TWISTED_D: FieldElement56 =
FieldElement56(fiat_p448_tight_field_element([
156327,
0,
0,
0,
72057594037927935,
72057594037927935,
72057594037927935,
72057594037927935,
]));

/// Edwards `d`, equals to -39081
pub const EDWARDS_D: FieldElement56 = FieldElement56([
pub const EDWARDS_D: FieldElement56 = FieldElement56(fiat_p448_tight_field_element([
144115188075816789,
144115188075855870,
144115188075855870,
Expand All @@ -26,13 +29,14 @@ pub const EDWARDS_D: FieldElement56 = FieldElement56([
144115188075855870,
144115188075855870,
144115188075855870,
]);
]));

/// Neg_Edwards `-d`, equals to 39081
pub const NEG_EDWARDS_D: FieldElement56 = FieldElement56([39081, 0, 0, 0, 0, 0, 0, 0]);
pub const NEG_EDWARDS_D: FieldElement56 =
FieldElement56(fiat_p448_tight_field_element([39081, 0, 0, 0, 0, 0, 0, 0]));

/// Twisted Edwards D equals `d-1`, equals to -39082
pub const TWISTED_D: FieldElement56 = FieldElement56([
pub const TWISTED_D: FieldElement56 = FieldElement56(fiat_p448_tight_field_element([
144115188075816788,
144115188075855870,
144115188075855870,
Expand All @@ -41,10 +45,10 @@ pub const TWISTED_D: FieldElement56 = FieldElement56([
144115188075855870,
144115188075855870,
144115188075855870,
]);
]));

/// Twice the Twisted Edwards d which equals to -78164
pub const TWO_TIMES_TWISTED_D: FieldElement56 = FieldElement56([
pub const TWO_TIMES_TWISTED_D: FieldElement56 = FieldElement56(fiat_p448_tight_field_element([
144115188075777706,
144115188075855870,
144115188075855870,
Expand All @@ -53,10 +57,10 @@ pub const TWO_TIMES_TWISTED_D: FieldElement56 = FieldElement56([
144115188075855870,
144115188075855870,
144115188075855870,
]);
]));

/// INVSQRT(a*d_2-1) where d_2 = 39082/39081
pub const DECAF_FACTOR: FieldElement56 = FieldElement56([
pub const DECAF_FACTOR: FieldElement56 = FieldElement56(fiat_p448_tight_field_element([
0x42ef0f45572736,
0x7bf6aa20ce5296,
0xf4fd6eded26033,
Expand All @@ -65,14 +69,15 @@ pub const DECAF_FACTOR: FieldElement56 = FieldElement56([
0x6aa0a1f1a7b8a5,
0x683bf68d722fa2,
0x22d962fbeb24f7,
]);
]));

/// 39082 used in the doubling procedure in montgomery ladder
pub const A_PLUS_TWO_OVER_FOUR: FieldElement56 = FieldElement56([39082, 0, 0, 0, 0, 0, 0, 0]);
pub const A_PLUS_TWO_OVER_FOUR: FieldElement56 =
FieldElement56(fiat_p448_tight_field_element([39082, 0, 0, 0, 0, 0, 0, 0]));

/// The basepoint of Ed448-Goldilocks
pub const GOLDILOCKS_BASE_POINT: ExtendedPoint = ExtendedPoint {
X: FieldElement56([
X: FieldElement56(fiat_p448_tight_field_element([
10880955091566686,
36276784145337894,
69571282115576635,
Expand All @@ -81,8 +86,8 @@ pub const GOLDILOCKS_BASE_POINT: ExtendedPoint = ExtendedPoint {
15440021224255559,
66747077793030847,
22264495316135181,
]),
Y: FieldElement56([
])),
Y: FieldElement56(fiat_p448_tight_field_element([
2385235625966100,
5396741696826776,
8134720567442877,
Expand All @@ -91,9 +96,9 @@ pub const GOLDILOCKS_BASE_POINT: ExtendedPoint = ExtendedPoint {
56121598560924524,
10283140089599689,
29624444337960636,
]),
Z: FieldElement56([1, 0, 0, 0, 0, 0, 0, 0]),
T: FieldElement56([
])),
Z: FieldElement56(fiat_p448_tight_field_element([1, 0, 0, 0, 0, 0, 0, 0])),
T: FieldElement56(fiat_p448_tight_field_element([
1796939199780339,
45174008172060139,
40732174862907279,
Expand All @@ -102,12 +107,12 @@ pub const GOLDILOCKS_BASE_POINT: ExtendedPoint = ExtendedPoint {
41035719659624511,
30626637035688077,
56117654178374172,
]),
])),
};

/// The basepoint of the Twisted Edwards curve which is 2-isogenous to Ed448-Goldilocks
pub const TWISTED_EDWARDS_BASE_POINT: TwExtendedPoint = TwExtendedPoint {
X: FieldElement56([
X: FieldElement56(fiat_p448_tight_field_element([
0,
72057594037927936,
72057594037927935,
Expand All @@ -116,8 +121,8 @@ pub const TWISTED_EDWARDS_BASE_POINT: TwExtendedPoint = TwExtendedPoint {
72057594037927935,
72057594037927935,
36028797018963967,
]),
Y: FieldElement56([
])),
Y: FieldElement56(fiat_p448_tight_field_element([
27155415521118820,
3410937204744648,
19376965222209947,
Expand All @@ -126,9 +131,9 @@ pub const TWISTED_EDWARDS_BASE_POINT: TwExtendedPoint = TwExtendedPoint {
10141917371396176,
59827755213158602,
37445921829569158,
]),
Z: FieldElement56([1, 0, 0, 0, 0, 0, 0, 0]),
T: FieldElement56([
])),
Z: FieldElement56(fiat_p448_tight_field_element([1, 0, 0, 0, 0, 0, 0, 0])),
T: FieldElement56(fiat_p448_tight_field_element([
64114820220813573,
27592348249940115,
21918321435874307,
Expand All @@ -137,5 +142,5 @@ pub const TWISTED_EDWARDS_BASE_POINT: TwExtendedPoint = TwExtendedPoint {
63575698147485199,
22766751209138687,
30740600843388580,
]),
])),
};
74 changes: 38 additions & 36 deletions src/field/fiat_u64/prime_field.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,8 +10,14 @@ use subtle::{Choice, ConditionallyNegatable, ConditionallySelectable};

// XXX: Check if the Serialisation procedure in FieldElement56 is consistent with FieldElement28

#[derive(Copy, Clone, Debug)]
pub struct FieldElement56(pub(crate) [u64; 8]);
#[derive(Copy, Clone)]
pub struct FieldElement56(pub(crate) fiat_p448_tight_field_element);

impl std::fmt::Debug for FieldElement56 {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_tuple("FieldElement56").field(&self.0 .0).finish()
}
}

////
/// Trait Implementations
Expand All @@ -33,7 +39,11 @@ impl Mul<&FieldElement56> for &FieldElement56 {
type Output = FieldElement56;
fn mul(self, rhs: &FieldElement56) -> Self::Output {
let mut result = FieldElement56::zero();
fiat_p448_carry_mul(&mut result.0, &self.0, &rhs.0);
let mut self_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_relax(&mut self_loose, &self.0);
let mut rhs_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_relax(&mut rhs_loose, &rhs.0);
fiat_p448_carry_mul(&mut result.0, &self_loose, &rhs_loose);
result
}
}
Expand All @@ -53,17 +63,21 @@ impl Mul<FieldElement56> for FieldElement56 {
impl Add<FieldElement56> for FieldElement56 {
type Output = FieldElement56;
fn add(self, rhs: FieldElement56) -> Self::Output {
let mut inter_res = self.add_no_reduce(&rhs);
inter_res.strong_reduce();
inter_res
let mut result_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_add(&mut result_loose, &self.0, &rhs.0);
let mut result = FieldElement56::zero();
fiat_p448_carry(&mut result.0, &result_loose);
result
}
}
impl Sub<FieldElement56> for FieldElement56 {
type Output = FieldElement56;
fn sub(self, rhs: FieldElement56) -> Self::Output {
let mut inter_res = self.sub_no_reduce(&rhs);
inter_res.strong_reduce();
inter_res
let mut result_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_sub(&mut result_loose, &self.0, &rhs.0);
let mut result = FieldElement56::zero();
fiat_p448_carry(&mut result.0, &result_loose);
result
}
}

Expand All @@ -81,7 +95,7 @@ impl ConditionallySelectable for FieldElement56 {
choice: Choice,
) -> FieldElement56 {
let mut result = FieldElement56::zero();
fiat_p448_selectznz(&mut result.0, choice.unwrap_u8(), &a.0, &b.0);
fiat_p448_selectznz(&mut (result.0).0, choice.unwrap_u8(), &(a.0).0, &(b.0).0);
result
}
}
Expand All @@ -98,13 +112,13 @@ impl Default for FieldElement56 {

impl FieldElement56 {
pub const fn zero() -> FieldElement56 {
FieldElement56([0; 8])
FieldElement56(fiat_p448_tight_field_element([0; 8]))
}
pub const fn one() -> FieldElement56 {
FieldElement56([1, 0, 0, 0, 0, 0, 0, 0])
FieldElement56(fiat_p448_tight_field_element([1, 0, 0, 0, 0, 0, 0, 0]))
}
pub fn minus_one() -> FieldElement56 {
FieldElement56([
FieldElement56(fiat_p448_tight_field_element([
144115188075855869,
144115188075855870,
144115188075855870,
Expand All @@ -113,7 +127,7 @@ impl FieldElement56 {
144115188075855870,
144115188075855870,
144115188075855870,
])
]))
}
}

Expand All @@ -133,7 +147,7 @@ impl FieldElement56 {
impl FieldElement56 {
/// Helper function for internally constructing a field element
pub(crate) const fn from_raw_slice(slice: [u64; 8]) -> FieldElement56 {
FieldElement56(slice)
FieldElement56(fiat_p448_tight_field_element(slice))
}

/// This does not check if the encoding is canonical (ie if the input is reduced)
Expand All @@ -156,40 +170,28 @@ impl FieldElement56 {
impl FieldElement56 {
/// Squares a field element
pub(crate) fn square(&self) -> FieldElement56 {
let mut self_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_relax(&mut self_loose, &self.0);
let mut result = FieldElement56::zero();
fiat_p448_carry_square(&mut result.0, &self.0);
fiat_p448_carry_square(&mut result.0, &self_loose);
result
}
/// Negates a field element
pub(crate) fn negate(&self) -> FieldElement56 {
let mut result_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_opp(&mut result_loose, &self.0);
let mut result = FieldElement56::zero();
fiat_p448_opp(&mut result.0, &self.0);
let cloned = result.clone();
fiat_p448_carry(&mut result.0, &cloned.0);
fiat_p448_carry(&mut result.0, &result_loose);
result
}

/// Reduces the field element to a canonical representation
/// This is used when checking equality between two field elements and
/// when encoding a field element
pub(crate) fn strong_reduce(&mut self) {
let cloned = self.clone(); // XXX: Cannot borrow mutably and immutably
fiat_p448_carry(&mut self.0, &cloned.0);
}

/// Adds two field elements together
/// Result is not reduced
pub(crate) fn add_no_reduce(&self, rhs: &FieldElement56) -> FieldElement56 {
let mut result = FieldElement56::zero();
fiat_p448_add(&mut result.0, &self.0, &rhs.0);
result
}
/// Subtracts the two field elements from each other
/// Result is not reduced
pub(crate) fn sub_no_reduce(&self, rhs: &FieldElement56) -> FieldElement56 {
let mut result = FieldElement56::zero();
fiat_p448_sub(&mut result.0, &self.0, &rhs.0);
result
let mut self_loose = fiat_p448_loose_field_element([0; 8]);
fiat_p448_relax(&mut self_loose, &self.0);
fiat_p448_carry(&mut self.0, &self_loose);
}
}

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