Add prime-field crate

prime-field introduces a macro to generate a prime field, in its entitrety,
de-duplicating code across minimal-ed448, embedwards25519, and secq256k1.

.github/workflows/crypto-tests.yml

@@ -35,6 +35,9 @@ jobs:
             -p ciphersuite-kp256 \
             -p multiexp \
             -p schnorr-signatures \
+            -p prime-field \
+            -p secq256k1 \
+            -p embedwards25519 \
             -p dkg \
             -p dkg-recovery \
             -p dkg-dealer \

Cargo.lock

@@ -2298,7 +2298,19 @@ checksum = "0dc92fb57ca44df6db8059111ab3af99a63d5d0f8375d9972e319a379c6bab76"
 dependencies = [
  "generic-array 0.14.7",
  "rand_core 0.6.4",
- "serdect",
+ "serdect 0.2.0",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "crypto-bigint"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96272c2ff28b807e09250b180ad1fb7889a3258f7455759b5c3c58b719467130"
+dependencies = [
+ "num-traits",
+ "serdect 0.3.0",
  "subtle",
  "zeroize",
 ]
@@ -2419,7 +2431,7 @@ name = "dalek-ff-group"
 version = "0.4.4"
 dependencies = [
  "ciphersuite 0.4.2",
- "crypto-bigint",
+ "crypto-bigint 0.5.5",
  "curve25519-dalek",
  "digest 0.10.7",
  "ff",
@@ -2505,7 +2517,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d162beedaa69905488a8da94f5ac3edb4dd4788b732fadb7bd120b2625c1976"
 dependencies = [
  "data-encoding",
- "syn 1.0.109",
+ "syn 2.0.106",
 ]
 
 [[package]]
@@ -2884,7 +2896,7 @@ dependencies = [
  "digest 0.10.7",
  "elliptic-curve",
  "rfc6979",
- "serdect",
+ "serdect 0.2.0",
  "signature",
  "spki",
 ]
@@ -2956,7 +2968,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5e6043086bf7973472e0c7dff2142ea0b680d30e18d9cc40f267efbf222bd47"
 dependencies = [
  "base16ct",
- "crypto-bigint",
+ "crypto-bigint 0.5.5",
  "digest 0.10.7",
  "ff",
  "generic-array 0.14.7",
@@ -2964,7 +2976,7 @@ dependencies = [
  "pkcs8",
  "rand_core 0.6.4",
  "sec1",
- "serdect",
+ "serdect 0.2.0",
  "subtle",
  "tap",
  "zeroize",
@@ -2976,7 +2988,6 @@ version = "0.1.0"
 dependencies = [
  "blake2",
  "ciphersuite 0.4.2",
- "crypto-bigint",
  "dalek-ff-group",
  "ec-divisors",
  "ff-group-tests",
@@ -2984,10 +2995,9 @@ dependencies = [
  "generic-array 1.2.0",
  "hex",
  "hex-literal",
+ "prime-field",
  "rand_core 0.6.4",
- "rustversion",
  "std-shims",
- "subtle",
  "zeroize",
 ]
 
@@ -4181,7 +4191,7 @@ dependencies = [
  "httpdate",
  "itoa",
  "pin-project-lite",
- "socket2 0.4.10",
+ "socket2 0.5.8",
  "tokio",
  "tower-service",
  "tracing",
@@ -4672,7 +4682,7 @@ dependencies = [
  "ecdsa",
  "elliptic-curve",
  "once_cell",
- "serdect",
+ "serdect 0.2.0",
  "sha2 0.10.9",
 ]
 
@@ -4752,7 +4762,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "07033963ba89ebaf1584d767badaa2e8fcec21aedea6b8c0346d487d49c28667"
 dependencies = [
  "cfg-if",
- "windows-targets 0.48.5",
+ "windows-targets 0.53.3",
 ]
 
 [[package]]
@@ -5934,16 +5944,11 @@ name = "minimal-ed448"
 version = "0.4.2"
 dependencies = [
  "ciphersuite 0.4.2",
- "crypto-bigint",
- "ff",
  "ff-group-tests",
- "generic-array 1.2.0",
- "group",
  "hex",
+ "prime-field",
  "rand_core 0.6.4",
- "rustversion",
  "sha3",
- "subtle",
  "zeroize",
 ]
 
@@ -6099,7 +6104,7 @@ name = "monero-generators"
 version = "0.4.0"
 source = "git+https://github.com/monero-oxide/monero-oxide?rev=6966575e05fe09b77674c46984b21686ed9304ff#6966575e05fe09b77674c46984b21686ed9304ff"
 dependencies = [
- "crypto-bigint",
+ "crypto-bigint 0.5.5",
  "curve25519-dalek",
  "dalek-ff-group",
  "group",
@@ -6610,7 +6615,7 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77e878c846a8abae00dd069496dbe8751b16ac1c3d6bd2a7283a938e8228f90d"
 dependencies = [
- "proc-macro-crate 1.3.1",
+ "proc-macro-crate 3.2.0",
  "proc-macro2",
  "quote",
  "syn 2.0.106",
@@ -7215,6 +7220,19 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "prime-field"
+version = "0.1.0"
+dependencies = [
+ "crypto-bigint 0.6.1",
+ "ff",
+ "ff-group-tests",
+ "paste",
+ "rand_core 0.6.4",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "primeorder"
 version = "0.13.6"
@@ -9450,7 +9468,7 @@ dependencies = [
  "der",
  "generic-array 0.14.7",
  "pkcs8",
- "serdect",
+ "serdect 0.2.0",
  "subtle",
  "zeroize",
 ]
@@ -9520,8 +9538,8 @@ dependencies = [
  "hex",
  "hex-literal",
  "k256",
+ "prime-field",
  "rand_core 0.6.4",
- "rustversion",
  "std-shims",
 ]
 
@@ -10159,6 +10177,7 @@ dependencies = [
  "flexible-transcript",
  "minimal-ed448",
  "multiexp",
+ "prime-field",
  "schnorr-signatures",
  "secq256k1",
 ]
@@ -10799,6 +10818,16 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serdect"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f42f67da2385b51a5f9652db9c93d78aeaf7610bf5ec366080b6de810604af53"
+dependencies = [
+ "base16ct",
+ "serde",
+]
+
 [[package]]
 name = "sha-1"
 version = "0.9.8"
@@ -13283,7 +13312,7 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0978bf7171b3d90bac376700cb56d606feb40f251a475a5d6634613564460b22"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]

Cargo.toml

@@ -39,6 +39,7 @@ members = [
   "crypto/multiexp",
   "crypto/schnorr",
 
+  "crypto/prime-field",
   "crypto/evrf/secq256k1",
   "crypto/evrf/embedwards25519",
 

crypto/ed448/Cargo.toml

@@ -7,7 +7,7 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/ed448"
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["ed448", "ff", "group"]
 edition = "2021"
-rust-version = "1.83"
+rust-version = "1.86"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -17,22 +17,13 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
-rustversion = "1"
+zeroize = { version = "1", default-features = false, features = ["zeroize_derive"] }
-
-rand_core = { version = "0.6", default-features = false }
-
-zeroize = { version = "^1.5", default-features = false, features = ["zeroize_derive"] }
-subtle = { version = "^2.4", default-features = false }
 
 sha3 = { version = "0.10", default-features = false }
 
-ff = { version = "0.13", default-features = false, features = ["bits"] }
+prime-field = { path = "../prime-field", default-features = false }
-group = { version = "0.13", default-features = false }
 ciphersuite = { path = "../ciphersuite", default-features = false }
 
-generic-array = { version = "1", default-features = false }
-crypto-bigint = { version = "0.5", default-features = false, features = ["zeroize"] }
-
 [dev-dependencies]
 hex = { version = "0.4", default-features = false, features = ["std"] }
 
@@ -41,6 +32,6 @@ rand_core = { version = "0.6", default-features = false, features = ["std"] }
 ff-group-tests = { path = "../ff-group-tests" }
 
 [features]
-alloc = ["zeroize/alloc", "ciphersuite/alloc"]
+alloc = ["zeroize/alloc", "prime-field/alloc", "ciphersuite/alloc"]
-std = ["alloc", "rand_core/std", "zeroize/std", "subtle/std", "sha3/std", "ff/std", "ciphersuite/std"]
+std = ["alloc", "zeroize/std", "sha3/std", "prime-field/std", "ciphersuite/std"]
 default = ["std"]

crypto/ed448/src/backend.rs

@@ -1,311 +0,0 @@
-use zeroize::Zeroize;
-
-// Use black_box when possible
-#[rustversion::since(1.66)]
-mod black_box {
-  pub(crate) fn black_box<T>(val: T) -> T {
-    #[allow(clippy::incompatible_msrv)]
-    core::hint::black_box(val)
-  }
-}
-#[rustversion::before(1.66)]
-mod black_box {
-  pub(crate) fn black_box<T>(val: T) -> T {
-    val
-  }
-}
-use black_box::black_box;
-
-pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
-  let bit_ref = black_box(bit_ref);
-
-  let mut bit = black_box(*bit_ref);
-  #[allow(clippy::cast_lossless)]
-  let res = black_box(bit as u8);
-  bit.zeroize();
-  debug_assert!((res | 1) == 1);
-
-  bit_ref.zeroize();
-  res
-}
-
-macro_rules! math_op {
-  (
-    $Value: ident,
-    $Other: ident,
-    $Op: ident,
-    $op_fn: ident,
-    $Assign: ident,
-    $assign_fn: ident,
-    $function: expr
-  ) => {
-    impl $Op<$Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: $Other) -> Self::Output {
-        $Value($function(self.0, other.0))
-      }
-    }
-    impl $Assign<$Other> for $Value {
-      fn $assign_fn(&mut self, other: $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-    impl<'a> $Op<&'a $Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: &'a $Other) -> Self::Output {
-        $Value($function(self.0, other.0))
-      }
-    }
-    impl<'a> $Assign<&'a $Other> for $Value {
-      fn $assign_fn(&mut self, other: &'a $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-  };
-}
-
-macro_rules! from_wrapper {
-  ($wrapper: ident, $inner: ident, $uint: ident) => {
-    impl From<$uint> for $wrapper {
-      fn from(a: $uint) -> $wrapper {
-        $wrapper(Residue::new(&$inner::from(a)))
-      }
-    }
-  };
-}
-
-macro_rules! field {
-  (
-    $FieldName: ident,
-    $ResidueType: ident,
-
-    $MODULUS_STR: ident,
-    $MODULUS: ident,
-    $WIDE_MODULUS: ident,
-
-    $NUM_BITS: literal,
-
-    $MULTIPLICATIVE_GENERATOR: literal,
-    $DELTA: expr,
-  ) => {
-    use core::{
-      ops::{Add, AddAssign, Neg, Sub, SubAssign, Mul, MulAssign},
-      iter::{Sum, Product},
-    };
-
-    use subtle::{Choice, CtOption, ConstantTimeEq, ConstantTimeLess, ConditionallySelectable};
-    use rand_core::RngCore;
-
-    use generic_array::{typenum::U57, GenericArray};
-    use crypto_bigint::{Integer, NonZero, Encoding, impl_modulus};
-
-    use ff::{Field, PrimeField, FieldBits, PrimeFieldBits, helpers::sqrt_ratio_generic};
-
-    use $crate::backend::u8_from_bool;
-
-    fn reduce(x: U896) -> U448 {
-      U448::from_le_slice(&x.rem(&NonZero::new($WIDE_MODULUS).unwrap()).to_le_bytes()[.. 56])
-    }
-
-    impl ConstantTimeEq for $FieldName {
-      fn ct_eq(&self, other: &Self) -> Choice {
-        self.0.ct_eq(&other.0)
-      }
-    }
-
-    impl ConditionallySelectable for $FieldName {
-      fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
-        $FieldName(Residue::conditional_select(&a.0, &b.0, choice))
-      }
-    }
-
-    math_op!($FieldName, $FieldName, Add, add, AddAssign, add_assign, |x: $ResidueType, y| x
-      .add(&y));
-    math_op!($FieldName, $FieldName, Sub, sub, SubAssign, sub_assign, |x: $ResidueType, y| x
-      .sub(&y));
-    math_op!($FieldName, $FieldName, Mul, mul, MulAssign, mul_assign, |x: $ResidueType, y| x
-      .mul(&y));
-
-    from_wrapper!($FieldName, U448, u8);
-    from_wrapper!($FieldName, U448, u16);
-    from_wrapper!($FieldName, U448, u32);
-    from_wrapper!($FieldName, U448, u64);
-    from_wrapper!($FieldName, U448, u128);
-
-    impl Neg for $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> $FieldName {
-        $FieldName(self.0.neg())
-      }
-    }
-
-    impl<'a> Neg for &'a $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> Self::Output {
-        (*self).neg()
-      }
-    }
-
-    impl $FieldName {
-      /// Perform an exponentiation.
-      pub fn pow(&self, other: $FieldName) -> $FieldName {
-        let mut table = [$FieldName(Residue::ONE); 16];
-        table[1] = *self;
-        for i in 2 .. 16 {
-          table[i] = table[i - 1] * self;
-        }
-
-        let mut res = $FieldName(Residue::ONE);
-        let mut bits = 0;
-        for (i, mut bit) in other.to_le_bits().iter_mut().rev().enumerate() {
-          bits <<= 1;
-          let mut bit = u8_from_bool(&mut bit);
-          bits |= bit;
-          bit.zeroize();
-
-          if ((i + 1) % 4) == 0 {
-            if i != 3 {
-              for _ in 0 .. 4 {
-                res *= res;
-              }
-            }
-
-            let mut scale_by = $FieldName(Residue::ONE);
-            #[allow(clippy::needless_range_loop)]
-            for i in 0 .. 16 {
-              #[allow(clippy::cast_possible_truncation)] // Safe since 0 .. 16
-              {
-                scale_by = <_>::conditional_select(&scale_by, &table[i], bits.ct_eq(&(i as u8)));
-              }
-            }
-            res *= scale_by;
-            bits = 0;
-          }
-        }
-        res
-      }
-    }
-
-    impl Field for $FieldName {
-      const ZERO: Self = $FieldName(Residue::ZERO);
-      const ONE: Self = $FieldName(Residue::ONE);
-
-      fn random(mut rng: impl RngCore) -> Self {
-        let mut bytes = [0; 112];
-        rng.fill_bytes(&mut bytes);
-        $FieldName(Residue::new(&reduce(U896::from_le_slice(bytes.as_ref()))))
-      }
-
-      fn square(&self) -> Self {
-        *self * self
-      }
-      fn double(&self) -> Self {
-        *self + self
-      }
-
-      fn invert(&self) -> CtOption<Self> {
-        const NEG_2: $FieldName =
-          $FieldName($ResidueType::sub(&$ResidueType::ZERO, &$ResidueType::new(&U448::from_u8(2))));
-        CtOption::new(self.pow(NEG_2), !self.is_zero())
-      }
-
-      fn sqrt(&self) -> CtOption<Self> {
-        const MOD_1_4: $FieldName = $FieldName($ResidueType::new(
-          &$MODULUS.saturating_add(&U448::ONE).wrapping_div(&U448::from_u8(4)),
-        ));
-
-        let res = self.pow(MOD_1_4);
-        CtOption::new(res, res.square().ct_eq(self))
-      }
-
-      fn sqrt_ratio(num: &Self, div: &Self) -> (Choice, Self) {
-        sqrt_ratio_generic(num, div)
-      }
-    }
-
-    impl PrimeField for $FieldName {
-      type Repr = GenericArray<u8, U57>;
-
-      const MODULUS: &'static str = $MODULUS_STR;
-
-      const NUM_BITS: u32 = $NUM_BITS;
-      const CAPACITY: u32 = $NUM_BITS - 1;
-
-      const TWO_INV: Self = $FieldName($ResidueType::new(&U448::from_u8(2)).invert().0);
-
-      const MULTIPLICATIVE_GENERATOR: Self =
-        $FieldName(Residue::new(&U448::from_u8($MULTIPLICATIVE_GENERATOR)));
-      // True for both the Ed448 Scalar field and FieldElement field
-      const S: u32 = 1;
-
-      // Both fields have their root of unity as -1
-      const ROOT_OF_UNITY: Self =
-        $FieldName($ResidueType::sub(&$ResidueType::ZERO, &$ResidueType::new(&U448::ONE)));
-      const ROOT_OF_UNITY_INV: Self = $FieldName(Self::ROOT_OF_UNITY.0.invert().0);
-
-      const DELTA: Self = $FieldName(Residue::new(&U448::from_le_hex($DELTA)));
-
-      fn from_repr(bytes: Self::Repr) -> CtOption<Self> {
-        let res = U448::from_le_slice(&bytes[.. 56]);
-        CtOption::new($FieldName(Residue::new(&res)), res.ct_lt(&$MODULUS) & bytes[56].ct_eq(&0))
-      }
-      fn to_repr(&self) -> Self::Repr {
-        let mut repr = GenericArray::<u8, U57>::default();
-        repr[.. 56].copy_from_slice(&self.0.retrieve().to_le_bytes());
-        repr
-      }
-
-      fn is_odd(&self) -> Choice {
-        self.0.retrieve().is_odd()
-      }
-    }
-
-    impl PrimeFieldBits for $FieldName {
-      type ReprBits = [u8; 56];
-
-      fn to_le_bits(&self) -> FieldBits<Self::ReprBits> {
-        let mut repr = [0; 56];
-        repr.copy_from_slice(&self.to_repr()[.. 56]);
-        repr.into()
-      }
-
-      fn char_le_bits() -> FieldBits<Self::ReprBits> {
-        let mut repr = [0; 56];
-        repr.copy_from_slice(&MODULUS.to_le_bytes()[.. 56]);
-        repr.into()
-      }
-    }
-
-    impl Sum<$FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ZERO;
-        for item in iter {
-          res += item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Sum<&'a $FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().sum()
-      }
-    }
-
-    impl Product<$FieldName> for $FieldName {
-      fn product<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ONE;
-        for item in iter {
-          res *= item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Product<&'a $FieldName> for $FieldName {
-      fn product<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().product()
-      }
-    }
-  };
-}

crypto/ed448/src/ciphersuite.rs

@@ -8,10 +8,12 @@ use sha3::{
   Shake256,
 };
 
-use group::Group;
+use ciphersuite::{
-use crate::{Scalar, Point};
+  group::{ff::FromUniformBytes, Group},
+  Ciphersuite,
+};
 
-use ciphersuite::Ciphersuite;
+use crate::{Scalar, Point};
 
 /// Shake256, fixed to a 114-byte output, as used by Ed448.
 #[derive(Clone, Default)]
@@ -69,13 +71,16 @@ impl Ciphersuite for Ed448 {
   }
 
   fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
-    Scalar::wide_reduce(Self::H::digest([dst, data].concat()).as_ref().try_into().unwrap())
+    let digest = Self::H::digest([dst, data].concat());
+    let mut wide_scalar = [0; 114];
+    wide_scalar.copy_from_slice(digest.as_ref());
+    Scalar::from_uniform_bytes(&wide_scalar)
   }
 }
 
 #[test]
 fn test_ed448() {
-  use ff::PrimeField;
+  use ciphersuite::group::ff::PrimeField;
 
   ff_group_tests::group::test_prime_group_bits::<_, Point>(&mut rand_core::OsRng);
 
@@ -94,7 +99,7 @@ fn test_ed448() {
       .unwrap()
     )
     .to_repr()
-    .to_vec(),
+    .as_ref(),
     hex::decode(
       "\
 67a6f023e77361707c6e894c625e809e80f33fdb310810053ae29e28\
@@ -102,5 +107,6 @@ e7011f3193b9020e73c183a98cc3a519160ed759376dd92c94831622\
 00"
     )
     .unwrap()
+    .as_slice()
   );
 }

crypto/ed448/src/field.rs

@@ -1,53 +0,0 @@
-use zeroize::{DefaultIsZeroes, Zeroize};
-
-use crypto_bigint::{
-  U448, U896,
-  modular::constant_mod::{ResidueParams, Residue},
-};
-
-const MODULUS_STR: &str = concat!(
-  "fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
-  "ffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-);
-
-impl_modulus!(FieldModulus, U448, MODULUS_STR);
-pub(crate) type ResidueType = Residue<FieldModulus, { FieldModulus::LIMBS }>;
-
-/// Ed448 field element.
-#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
-pub struct FieldElement(pub(crate) ResidueType);
-
-impl DefaultIsZeroes for FieldElement {}
-
-// 2**448 - 2**224 - 1
-pub(crate) const MODULUS: U448 = U448::from_be_hex(MODULUS_STR);
-
-const WIDE_MODULUS: U896 = U896::from_be_hex(concat!(
-  "00000000000000000000000000000000000000000000000000000000",
-  "00000000000000000000000000000000000000000000000000000000",
-  "fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
-  "ffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
-));
-
-pub(crate) const Q_4: FieldElement = FieldElement(ResidueType::new(
-  &MODULUS.saturating_add(&U448::ONE).wrapping_div(&U448::from_u8(4)),
-));
-
-field!(
-  FieldElement,
-  ResidueType,
-  MODULUS_STR,
-  MODULUS,
-  WIDE_MODULUS,
-  448,
-  7,
-  concat!(
-    "31000000000000000000000000000000000000000000000000000000",
-    "00000000000000000000000000000000000000000000000000000000",
-  ),
-);
-
-#[test]
-fn test_field() {
-  ff_group_tests::prime_field::test_prime_field_bits::<_, FieldElement>(&mut rand_core::OsRng);
-}

crypto/ed448/src/lib.rs

@@ -1,19 +1,47 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![doc = include_str!("../README.md")]
 #![no_std]
-#![allow(clippy::redundant_closure_call)]
 
-#[macro_use]
+prime_field::odd_prime_field!(
-mod backend;
+  FieldElement,
+  // 2**448 - 2**224 - 1
+  concat!(
+    "00",
+    "fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
+    "ffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+  ),
+  "07",
+  false
+);
 
-mod scalar;
+prime_field::odd_prime_field!(
-pub use scalar::Scalar;
+  Scalar,
-
+  concat!(
-mod field;
+    "00",
-pub use field::FieldElement;
+    "3fffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+    "7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3",
+  ),
+  "02",
+  false
+);
 
 mod point;
 pub use point::Point;
 
 mod ciphersuite;
 pub use crate::ciphersuite::Ed448;
+
+pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
+  use core::hint::black_box;
+  use prime_field::zeroize::Zeroize;
+
+  let bit_ref = black_box(bit_ref);
+
+  let mut bit = black_box(*bit_ref);
+  let res = black_box(u8::from(bit));
+  bit.zeroize();
+  debug_assert!((res | 1) == 1);
+
+  bit_ref.zeroize();
+  res
+}

crypto/ed448/src/point.rs

@@ -3,50 +3,47 @@ use core::{
   iter::Sum,
 };
 
-use rand_core::RngCore;
+use prime_field::{
+  subtle::{Choice, CtOption, ConstantTimeEq, ConditionallySelectable, ConditionallyNegatable},
+  zeroize::Zeroize,
+  rand_core::RngCore,
+  crypto_bigint::U512,
+};
 
-use zeroize::Zeroize;
+use ciphersuite::group::{
-use subtle::{Choice, CtOption, ConstantTimeEq, ConditionallySelectable, ConditionallyNegatable};
-
-use crypto_bigint::{U448, modular::constant_mod::Residue};
-
-use group::{
   ff::{Field, PrimeField, PrimeFieldBits},
   Group, GroupEncoding,
   prime::PrimeGroup,
 };
 
-use crate::{
+use crate::{u8_from_bool, Scalar, FieldElement};
-  backend::u8_from_bool,
-  scalar::Scalar,
-  field::{ResidueType, FieldElement, Q_4},
-};
 
-const D: FieldElement =
+const G_Y: FieldElement = FieldElement::from(&U512::from_be_hex(concat!(
-  FieldElement(ResidueType::sub(&ResidueType::ZERO, &Residue::new(&U448::from_u16(39081))));
+  "0000000000000000",
-
-const G_Y: FieldElement = FieldElement(Residue::new(&U448::from_be_hex(concat!(
   "693f46716eb6bc248876203756c9c7624bea73736ca3984087789c1e",
   "05a0c2d73ad3ff1ce67c39c4fdbd132c4ed7c8ad9808795bf230fa14",
-))));
+)));
 
-const G_X: FieldElement = FieldElement(Residue::new(&U448::from_be_hex(concat!(
+const G_X: FieldElement = FieldElement::from(&U512::from_be_hex(concat!(
+  "0000000000000000",
   "4f1970c66bed0ded221d15a622bf36da9e146570470f1767ea6de324",
   "a3d3a46412ae1af72ab66511433b80e18b00938e2626a82bc70cc05e",
-))));
+)));
 
 fn recover_x(y: FieldElement) -> CtOption<FieldElement> {
+  #[allow(non_snake_case)]
+  let D = -<FieldElement as From<u16>>::from(39081u16);
+
   let ysq = y.square();
   #[allow(non_snake_case)]
   let D_ysq = D * ysq;
   (D_ysq - FieldElement::ONE).invert().and_then(|inverted| {
-    let temp = (ysq - FieldElement::ONE) * inverted;
+    let xsq = (ysq - FieldElement::ONE) * inverted;
-    let mut x = temp.pow(Q_4);
+    xsq.sqrt().and_then(|mut x| {
       x.conditional_negate(x.is_odd());
-
-    let xsq = x.square();
       CtOption::new(x, (xsq + ysq).ct_eq(&(FieldElement::ONE + (xsq * D_ysq))))
     })
+  })
 }
 
 /// Ed448 point.
@@ -104,6 +101,9 @@ impl ConditionallySelectable for Point {
 impl Add for Point {
   type Output = Point;
   fn add(self, other: Self) -> Self {
+    #[allow(non_snake_case)]
+    let D = -<FieldElement as From<u16>>::from(39081u16);
+
     // 12 muls, 7 additions, 4 negations
     let xcp = self.x * other.x;
     let ycp = self.y * other.y;
@@ -302,7 +302,7 @@ impl GroupEncoding for Point {
 
   fn from_bytes(bytes: &Self::Repr) -> CtOption<Self> {
     // Extract and clear the sign bit
-    let sign = Choice::from(bytes[56] >> 7);
+    let sign = Choice::from(bytes.as_ref()[56] >> 7);
     let mut bytes = *bytes;
     let mut_ref: &mut [u8] = bytes.as_mut();
     mut_ref[56] &= !(1 << 7);
@@ -350,63 +350,48 @@ fn generator() {
 
 #[test]
 fn torsion() {
-  use generic_array::GenericArray;
-
   // Uses the originally suggested generator which had torsion
-  let old_y = FieldElement::from_repr(*GenericArray::from_slice(
+  const TORSIONED_Y: &str = "\
-    &hex::decode(
-      "\
 12796c1532041525945f322e414d434467cfd5c57c9a9af2473b2775\
 8c921c4828b277ca5f2891fc4f3d79afdf29a64c72fb28b59c16fa51\
-00",
+00";
-    )
+  let mut repr = <FieldElement as PrimeField>::Repr::default();
-    .unwrap(),
+  repr.as_mut().copy_from_slice(&hex::decode(TORSIONED_Y).unwrap());
-  ))
+
-  .unwrap();
+  let old_y = FieldElement::from_repr(repr).unwrap();
   let old = Point { x: -recover_x(old_y).unwrap(), y: old_y, z: FieldElement::ONE };
   assert!(bool::from(!old.is_torsion_free()));
+
+  assert!(bool::from(Point::from_bytes(&old.to_bytes()).is_none()));
 }
 
 #[test]
 fn vector() {
-  use generic_array::GenericArray;
+  const TWO_G: &str = "\
-
-  assert_eq!(
-    Point::generator().double(),
-    Point::from_bytes(GenericArray::from_slice(
-      &hex::decode(
-        "\
 ed8693eacdfbeada6ba0cdd1beb2bcbb98302a3a8365650db8c4d88a\
 726de3b7d74d8835a0d76e03b0c2865020d659b38d04d74a63e905ae\
-80"
+80";
-      )
+  let mut two_g = <Point as GroupEncoding>::Repr::default();
-      .unwrap()
+  two_g.as_mut().copy_from_slice(&hex::decode(TWO_G).unwrap());
-    ))
+  assert_eq!(Point::generator().double(), Point::from_bytes(&two_g).unwrap());
-    .unwrap()
-  );
 
-  assert_eq!(
+  const SCALAR: &str = "\
-    Point::generator() *
-      Scalar::from_repr(*GenericArray::from_slice(
-        &hex::decode(
-          "\
 6298e1eef3c379392caaed061ed8a31033c9e9e3420726f23b404158\
 a401cd9df24632adfe6b418dc942d8a091817dd8bd70e1c72ba52f3c\
-00"
+00";
-        )
+  let mut scalar = <Scalar as PrimeField>::Repr::default();
-        .unwrap()
+  scalar.as_mut().copy_from_slice(&hex::decode(SCALAR).unwrap());
-      ))
+
-      .unwrap(),
+  const SCALED_G: &str = "\
-    Point::from_bytes(GenericArray::from_slice(
-      &hex::decode(
-        "\
 3832f82fda00ff5365b0376df705675b63d2a93c24c6e81d40801ba2\
 65632be10f443f95968fadb70d10786827f30dc001c8d0f9b7c1d1b0\
-00"
+00";
-      )
+  let mut scaled_g = <Point as GroupEncoding>::Repr::default();
-      .unwrap()
+  scaled_g.as_mut().copy_from_slice(&hex::decode(SCALED_G).unwrap());
-    ))
+
-    .unwrap()
+  assert_eq!(
+    Point::generator() * Scalar::from_repr(scalar).unwrap(),
+    Point::from_bytes(&scaled_g).unwrap()
   );
 }
 

crypto/ed448/src/scalar.rs

@@ -1,69 +0,0 @@
-use zeroize::{DefaultIsZeroes, Zeroize};
-
-use crypto_bigint::{
-  U448, U896, U1024,
-  modular::constant_mod::{ResidueParams, Residue},
-};
-
-const MODULUS_STR: &str = concat!(
-  "3fffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-  "7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3",
-);
-
-impl_modulus!(ScalarModulus, U448, MODULUS_STR);
-type ResidueType = Residue<ScalarModulus, { ScalarModulus::LIMBS }>;
-
-/// Ed448 Scalar field element.
-#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
-pub struct Scalar(pub(crate) ResidueType);
-
-impl DefaultIsZeroes for Scalar {}
-
-// 2**446 - 13818066809895115352007386748515426880336692474882178609894547503885
-pub(crate) const MODULUS: U448 = U448::from_be_hex(MODULUS_STR);
-
-const WIDE_MODULUS: U896 = U896::from_be_hex(concat!(
-  "00000000000000000000000000000000000000000000000000000000",
-  "00000000000000000000000000000000000000000000000000000000",
-  "3fffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-  "7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3",
-));
-
-const WIDE_REDUCTION_MODULUS: NonZero<U1024> = NonZero::from_uint(U1024::from_be_hex(concat!(
-  "00000000000000000000000000000000",
-  "00000000000000000000000000000000000000000000000000000000",
-  "00000000000000000000000000000000000000000000000000000000",
-  "3fffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-  "7cca23e9c44edb49aed63690216cc2728dc58f552378c292ab5844f3",
-)));
-
-field!(
-  Scalar,
-  ResidueType,
-  MODULUS_STR,
-  MODULUS,
-  WIDE_MODULUS,
-  446,
-  2,
-  concat!(
-    "04000000000000000000000000000000000000000000000000000000",
-    "00000000000000000000000000000000000000000000000000000000",
-  ),
-);
-
-impl Scalar {
-  /// Perform a wide reduction to obtain a non-biased Scalar.
-  pub fn wide_reduce(bytes: [u8; 114]) -> Scalar {
-    let mut bytes_128 = [0; 128];
-    bytes_128[.. 114].copy_from_slice(&bytes);
-    let wide = U1024::from_le_slice(&bytes_128);
-    Scalar(Residue::new(&U448::from_le_slice(
-      &wide.rem(&WIDE_REDUCTION_MODULUS).to_le_bytes()[.. 56],
-    )))
-  }
-}
-
-#[test]
-fn test_scalar() {
-  ff_group_tests::prime_field::test_prime_field_bits::<_, Scalar>(&mut rand_core::OsRng);
-}

crypto/evrf/embedwards25519/Cargo.toml

@@ -7,26 +7,22 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/evrf/embedw
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["curve25519", "ed25519", "ristretto255", "group"]
 edition = "2021"
-rust-version = "1.83"
+rust-version = "1.86"
 
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
-rustversion = "1"
 hex-literal = { version = "0.4", default-features = false }
 
 std-shims = { version = "0.1", path = "../../../common/std-shims", default-features = false, optional = true }
 
-rand_core = { version = "0.6", default-features = false }
-
 zeroize = { version = "^1.5", default-features = false, features = ["zeroize_derive"] }
-subtle = { version = "^2.4", default-features = false }
 
 generic-array = { version = "1", default-features = false }
-crypto-bigint = { version = "0.5", default-features = false, features = ["zeroize"] }
 
+prime-field = { path = "../../prime-field", default-features = false }
 dalek-ff-group = { path = "../../dalek-ff-group", version = "0.4", default-features = false }
 
 blake2 = { version = "0.10", default-features = false }
@@ -42,6 +38,6 @@ rand_core = { version = "0.6", features = ["std"] }
 ff-group-tests = { path = "../../ff-group-tests" }
 
 [features]
-alloc = ["std-shims", "zeroize/alloc", "ciphersuite/alloc"]
+alloc = ["std-shims", "zeroize/alloc", "prime-field/alloc", "ciphersuite/alloc"]
-std = ["std-shims/std", "rand_core/std", "zeroize/std", "subtle/std", "blake2/std", "ciphersuite/std", "ec-divisors/std", "generalized-bulletproofs-ec-gadgets/std"]
+std = ["std-shims/std", "zeroize/std", "prime-field/std", "blake2/std", "ciphersuite/std", "ec-divisors/std", "generalized-bulletproofs-ec-gadgets/std"]
 default = ["std"]

crypto/evrf/embedwards25519/src/backend.rs

@@ -1,299 +0,0 @@
-use zeroize::Zeroize;
-
-// Use black_box when possible
-#[rustversion::since(1.66)]
-use core::hint::black_box;
-#[rustversion::before(1.66)]
-fn black_box<T>(val: T) -> T {
-  val
-}
-
-pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
-  let bit_ref = black_box(bit_ref);
-
-  let mut bit = black_box(*bit_ref);
-  let res = black_box(bit as u8);
-  bit.zeroize();
-  debug_assert!((res | 1) == 1);
-
-  bit_ref.zeroize();
-  res
-}
-
-macro_rules! math_op {
-  (
-    $Value: ident,
-    $Other: ident,
-    $Op: ident,
-    $op_fn: ident,
-    $Assign: ident,
-    $assign_fn: ident,
-    $function: expr
-  ) => {
-    impl $Op<$Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: $Other) -> Self::Output {
-        Self($function(self.0, other.0))
-      }
-    }
-    impl $Assign<$Other> for $Value {
-      fn $assign_fn(&mut self, other: $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-    impl<'a> $Op<&'a $Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: &'a $Other) -> Self::Output {
-        Self($function(self.0, other.0))
-      }
-    }
-    impl<'a> $Assign<&'a $Other> for $Value {
-      fn $assign_fn(&mut self, other: &'a $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-  };
-}
-
-macro_rules! from_wrapper {
-  ($wrapper: ident, $inner: ident, $uint: ident) => {
-    impl From<$uint> for $wrapper {
-      fn from(a: $uint) -> $wrapper {
-        Self(Residue::new(&$inner::from(a)))
-      }
-    }
-  };
-}
-
-macro_rules! field {
-  (
-    $FieldName: ident,
-    $ResidueType: ident,
-
-    $MODULUS_STR: ident,
-    $MODULUS: ident,
-    $WIDE_MODULUS: ident,
-
-    $NUM_BITS: literal,
-    $MULTIPLICATIVE_GENERATOR: literal,
-    $S: literal,
-    $ROOT_OF_UNITY: literal,
-    $DELTA: literal,
-  ) => {
-    use core::{
-      ops::{DerefMut, Add, AddAssign, Neg, Sub, SubAssign, Mul, MulAssign},
-      iter::{Sum, Product},
-    };
-
-    use subtle::{Choice, CtOption, ConstantTimeEq, ConstantTimeLess, ConditionallySelectable};
-    use rand_core::RngCore;
-
-    use crypto_bigint::{Integer, NonZero, Encoding, impl_modulus};
-
-    use ciphersuite::group::ff::{
-      Field, PrimeField, FieldBits, PrimeFieldBits, FromUniformBytes, helpers::sqrt_ratio_generic,
-    };
-
-    use $crate::backend::u8_from_bool;
-
-    fn reduce(x: U512) -> U256 {
-      U256::from_le_slice(&x.rem(&NonZero::new($WIDE_MODULUS).unwrap()).to_le_bytes()[.. 32])
-    }
-
-    impl ConstantTimeEq for $FieldName {
-      fn ct_eq(&self, other: &Self) -> Choice {
-        self.0.ct_eq(&other.0)
-      }
-    }
-
-    impl ConditionallySelectable for $FieldName {
-      fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
-        $FieldName(Residue::conditional_select(&a.0, &b.0, choice))
-      }
-    }
-
-    math_op!($FieldName, $FieldName, Add, add, AddAssign, add_assign, |x: $ResidueType, y| x
-      .add(&y));
-    math_op!($FieldName, $FieldName, Sub, sub, SubAssign, sub_assign, |x: $ResidueType, y| x
-      .sub(&y));
-    math_op!($FieldName, $FieldName, Mul, mul, MulAssign, mul_assign, |x: $ResidueType, y| x
-      .mul(&y));
-
-    from_wrapper!($FieldName, U256, u8);
-    from_wrapper!($FieldName, U256, u16);
-    from_wrapper!($FieldName, U256, u32);
-    from_wrapper!($FieldName, U256, u64);
-    from_wrapper!($FieldName, U256, u128);
-
-    impl Neg for $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> $FieldName {
-        Self(self.0.neg())
-      }
-    }
-
-    impl<'a> Neg for &'a $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> Self::Output {
-        (*self).neg()
-      }
-    }
-
-    impl $FieldName {
-      /// Perform an exponentation.
-      pub fn pow(&self, other: $FieldName) -> $FieldName {
-        let mut table = [Self(Residue::ONE); 16];
-        table[1] = *self;
-        for i in 2 .. 16 {
-          table[i] = table[i - 1] * self;
-        }
-
-        let mut res = Self(Residue::ONE);
-        let mut bits = 0;
-        for (i, mut bit) in other.to_le_bits().iter_mut().rev().enumerate() {
-          bits <<= 1;
-          let mut bit = u8_from_bool(bit.deref_mut());
-          bits |= bit;
-          bit.zeroize();
-
-          if ((i + 1) % 4) == 0 {
-            if i != 3 {
-              for _ in 0 .. 4 {
-                res *= res;
-              }
-            }
-
-            let mut factor = table[0];
-            for (j, candidate) in table[1 ..].iter().enumerate() {
-              let j = j + 1;
-              factor = Self::conditional_select(&factor, &candidate, usize::from(bits).ct_eq(&j));
-            }
-            res *= factor;
-            bits = 0;
-          }
-        }
-        res
-      }
-    }
-
-    impl Field for $FieldName {
-      const ZERO: Self = Self(Residue::ZERO);
-      const ONE: Self = Self(Residue::ONE);
-
-      fn random(mut rng: impl RngCore) -> Self {
-        let mut bytes = [0; 64];
-        rng.fill_bytes(&mut bytes);
-        $FieldName(Residue::new(&reduce(U512::from_le_slice(bytes.as_ref()))))
-      }
-
-      fn square(&self) -> Self {
-        Self(self.0.square())
-      }
-      fn double(&self) -> Self {
-        *self + self
-      }
-
-      fn invert(&self) -> CtOption<Self> {
-        let res = self.0.invert();
-        CtOption::new(Self(res.0), res.1.into())
-      }
-
-      fn sqrt(&self) -> CtOption<Self> {
-        // (p + 1) // 4, as valid since p % 4 == 3
-        let mod_plus_one_div_four = $MODULUS.saturating_add(&U256::ONE).wrapping_div(&(4u8.into()));
-        let res = self.pow(Self($ResidueType::new_checked(&mod_plus_one_div_four).unwrap()));
-        CtOption::new(res, res.square().ct_eq(self))
-      }
-
-      fn sqrt_ratio(num: &Self, div: &Self) -> (Choice, Self) {
-        sqrt_ratio_generic(num, div)
-      }
-    }
-
-    impl PrimeField for $FieldName {
-      type Repr = [u8; 32];
-
-      const MODULUS: &'static str = $MODULUS_STR;
-
-      const NUM_BITS: u32 = $NUM_BITS;
-      const CAPACITY: u32 = $NUM_BITS - 1;
-
-      const TWO_INV: Self = $FieldName($ResidueType::new(&U256::from_u8(2)).invert().0);
-
-      const MULTIPLICATIVE_GENERATOR: Self =
-        Self(Residue::new(&U256::from_u8($MULTIPLICATIVE_GENERATOR)));
-      const S: u32 = $S;
-
-      const ROOT_OF_UNITY: Self = $FieldName(Residue::new(&U256::from_be_hex($ROOT_OF_UNITY)));
-      const ROOT_OF_UNITY_INV: Self = Self(Self::ROOT_OF_UNITY.0.invert().0);
-
-      const DELTA: Self = $FieldName(Residue::new(&U256::from_be_hex($DELTA)));
-
-      fn from_repr(bytes: Self::Repr) -> CtOption<Self> {
-        let res = U256::from_le_slice(&bytes);
-        CtOption::new($FieldName(Residue::new(&res)), res.ct_lt(&$MODULUS))
-      }
-      fn to_repr(&self) -> Self::Repr {
-        let mut repr = [0; 32];
-        repr.copy_from_slice(&self.0.retrieve().to_le_bytes());
-        repr
-      }
-
-      fn is_odd(&self) -> Choice {
-        self.0.retrieve().is_odd()
-      }
-    }
-
-    impl PrimeFieldBits for $FieldName {
-      type ReprBits = [u8; 32];
-
-      fn to_le_bits(&self) -> FieldBits<Self::ReprBits> {
-        self.to_repr().into()
-      }
-
-      fn char_le_bits() -> FieldBits<Self::ReprBits> {
-        let mut repr = [0; 32];
-        repr.copy_from_slice(&MODULUS.to_le_bytes());
-        repr.into()
-      }
-    }
-
-    impl FromUniformBytes<64> for $FieldName {
-      fn from_uniform_bytes(bytes: &[u8; 64]) -> Self {
-        $FieldName(Residue::new(&reduce(U512::from_le_slice(bytes))))
-      }
-    }
-
-    impl Sum<$FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ZERO;
-        for item in iter {
-          res += item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Sum<&'a $FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().sum()
-      }
-    }
-
-    impl Product<$FieldName> for $FieldName {
-      fn product<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ONE;
-        for item in iter {
-          res *= item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Product<&'a $FieldName> for $FieldName {
-      fn product<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().product()
-      }
-    }
-  };
-}

crypto/evrf/embedwards25519/src/lib.rs

@@ -8,19 +8,38 @@ use std_shims::prelude::*;
 use std_shims::io::{self, Read};
 
 use generic_array::typenum::{Sum, Diff, Quot, U, U1, U2};
-use ciphersuite::group::{ff::PrimeField, Group};
+use ciphersuite::group::{
+  ff::{PrimeField, FromUniformBytes},
+  Group,
+};
 
-#[macro_use]
+prime_field::odd_prime_field!(
-mod backend;
+  Scalar,
-
+  "0fffffffffffffffffffffffffffffffe53f4debb78ff96877063f0306eef96b",
-mod scalar;
+  "0a",
-pub use scalar::Scalar;
+  false
+);
 
 pub use dalek_ff_group::Scalar as FieldElement;
 
 mod point;
 pub use point::Point;
 
+pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
+  use core::hint::black_box;
+  use prime_field::zeroize::Zeroize;
+
+  let bit_ref = black_box(bit_ref);
+
+  let mut bit = black_box(*bit_ref);
+  let res = black_box(u8::from(bit));
+  bit.zeroize();
+  debug_assert!((res | 1) == 1);
+
+  bit_ref.zeroize();
+  res
+}
+
 /// Ciphersuite for Embedwards25519.
 ///
 /// hash_to_F is implemented with a naive concatenation of the dst and data, allowing transposition
@@ -41,7 +60,9 @@ impl ciphersuite::Ciphersuite for Embedwards25519 {
 
   fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
     use blake2::Digest;
-    Scalar::wide_reduce(Self::H::digest([dst, data].concat()).as_slice().try_into().unwrap())
+    <Scalar as FromUniformBytes<64>>::from_uniform_bytes(
+      &Self::H::digest([dst, data].concat()).into(),
+    )
   }
 
   // We override the provided impl, which compares against the reserialization, because

crypto/evrf/embedwards25519/src/point.rs

@@ -3,10 +3,11 @@ use core::{
   iter::Sum,
 };
 
-use rand_core::RngCore;
+use prime_field::{
-
+  subtle::{Choice, CtOption, ConstantTimeEq, ConditionallySelectable},
-use zeroize::Zeroize;
+  zeroize::Zeroize,
-use subtle::{Choice, CtOption, ConstantTimeEq, ConditionallySelectable};
+  rand_core::RngCore,
+};
 
 use ciphersuite::group::{
   ff::{Field, PrimeField, PrimeFieldBits},
@@ -14,7 +15,7 @@ use ciphersuite::group::{
   prime::PrimeGroup,
 };
 
-use crate::{backend::u8_from_bool, Scalar, FieldElement};
+use crate::{u8_from_bool, Scalar, FieldElement};
 
 #[allow(non_snake_case)]
 fn B() -> FieldElement {

crypto/evrf/embedwards25519/src/scalar.rs

@@ -1,52 +0,0 @@
-use zeroize::{DefaultIsZeroes, Zeroize};
-
-use crypto_bigint::{
-  U256, U512,
-  modular::constant_mod::{ResidueParams, Residue},
-};
-
-const MODULUS_STR: &str = "0fffffffffffffffffffffffffffffffe53f4debb78ff96877063f0306eef96b";
-
-impl_modulus!(EmbedwardsQ, U256, MODULUS_STR);
-type ResidueType = Residue<EmbedwardsQ, { EmbedwardsQ::LIMBS }>;
-
-/// The Scalar field of Embedwards25519.
-///
-/// This is equivalent to the field secp256k1 is defined over.
-#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
-#[repr(C)]
-pub struct Scalar(pub(crate) ResidueType);
-
-impl DefaultIsZeroes for Scalar {}
-
-pub(crate) const MODULUS: U256 = U256::from_be_hex(MODULUS_STR);
-
-const WIDE_MODULUS: U512 = U512::from_be_hex(concat!(
-  "0000000000000000000000000000000000000000000000000000000000000000",
-  "0fffffffffffffffffffffffffffffffe53f4debb78ff96877063f0306eef96b",
-));
-
-field!(
-  Scalar,
-  ResidueType,
-  MODULUS_STR,
-  MODULUS,
-  WIDE_MODULUS,
-  252,
-  10,
-  1,
-  "0fffffffffffffffffffffffffffffffe53f4debb78ff96877063f0306eef96a",
-  "0000000000000000000000000000000000000000000000000000000000000064",
-);
-
-impl Scalar {
-  /// Perform a wide reduction, presumably to obtain a non-biased Scalar field element.
-  pub fn wide_reduce(bytes: [u8; 64]) -> Scalar {
-    Scalar(Residue::new(&reduce(U512::from_le_slice(bytes.as_ref()))))
-  }
-}
-
-#[test]
-fn test_scalar_field() {
-  ff_group_tests::prime_field::test_prime_field_bits::<_, Scalar>(&mut rand_core::OsRng);
-}

crypto/evrf/secq256k1/Cargo.toml

@@ -7,19 +7,19 @@ repository = "https://github.com/serai-dex/serai/tree/develop/crypto/evrf/secq25
 authors = ["Luke Parker <lukeparker5132@gmail.com>"]
 keywords = ["secp256k1", "secq256k1", "group"]
 edition = "2021"
-rust-version = "1.85"
+rust-version = "1.86"
 
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
-rustversion = "1"
 hex-literal = { version = "0.4", default-features = false }
 
 std-shims = { version = "0.1", path = "../../../common/std-shims", default-features = false, optional = true }
 
 k256 = { version = "0.13", default-features = false, features = ["arithmetic"] }
+prime-field = { path = "../../prime-field", default-features = false }
 
 blake2 = { version = "0.10", default-features = false }
 ciphersuite = { path = "../../ciphersuite", version = "0.4", default-features = false }
@@ -34,6 +34,6 @@ rand_core = { version = "0.6", features = ["std"] }
 ff-group-tests = { path = "../../ff-group-tests" }
 
 [features]
-alloc = ["std-shims", "k256/alloc", "ciphersuite/alloc"]
+alloc = ["std-shims", "k256/alloc", "prime-field/alloc", "ciphersuite/alloc"]
-std = ["std-shims/std", "k256/std", "blake2/std", "ciphersuite/std", "ec-divisors/std", "generalized-bulletproofs-ec-gadgets/std"]
+std = ["std-shims/std", "k256/std", "prime-field/std", "blake2/std", "ciphersuite/std", "ec-divisors/std", "generalized-bulletproofs-ec-gadgets/std"]
 default = ["std"]

crypto/evrf/secq256k1/src/backend.rs

@@ -1,301 +0,0 @@
-use k256::elliptic_curve::zeroize::Zeroize;
-
-// Use black_box when possible
-#[rustversion::since(1.66)]
-use core::hint::black_box;
-#[rustversion::before(1.66)]
-fn black_box<T>(val: T) -> T {
-  val
-}
-
-pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
-  let bit_ref = black_box(bit_ref);
-
-  let mut bit = black_box(*bit_ref);
-  let res = black_box(bit as u8);
-  bit.zeroize();
-  debug_assert!((res | 1) == 1);
-
-  bit_ref.zeroize();
-  res
-}
-
-macro_rules! math_op {
-  (
-    $Value: ident,
-    $Other: ident,
-    $Op: ident,
-    $op_fn: ident,
-    $Assign: ident,
-    $assign_fn: ident,
-    $function: expr
-  ) => {
-    impl $Op<$Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: $Other) -> Self::Output {
-        Self($function(self.0, other.0))
-      }
-    }
-    impl $Assign<$Other> for $Value {
-      fn $assign_fn(&mut self, other: $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-    impl<'a> $Op<&'a $Other> for $Value {
-      type Output = $Value;
-      fn $op_fn(self, other: &'a $Other) -> Self::Output {
-        Self($function(self.0, other.0))
-      }
-    }
-    impl<'a> $Assign<&'a $Other> for $Value {
-      fn $assign_fn(&mut self, other: &'a $Other) {
-        self.0 = $function(self.0, other.0);
-      }
-    }
-  };
-}
-
-macro_rules! from_wrapper {
-  ($wrapper: ident, $inner: ident, $uint: ident) => {
-    impl From<$uint> for $wrapper {
-      fn from(a: $uint) -> $wrapper {
-        Self(Residue::new(&$inner::from(a)))
-      }
-    }
-  };
-}
-
-macro_rules! field {
-  (
-    $FieldName: ident,
-    $ResidueType: ident,
-
-    $MODULUS_STR: ident,
-    $MODULUS: ident,
-    $WIDE_MODULUS: ident,
-
-    $NUM_BITS: literal,
-    $MULTIPLICATIVE_GENERATOR: literal,
-    $S: literal,
-    $ROOT_OF_UNITY: literal,
-    $DELTA: literal,
-  ) => {
-    use core::{
-      ops::{DerefMut, Add, AddAssign, Neg, Sub, SubAssign, Mul, MulAssign},
-      iter::{Sum, Product},
-    };
-
-    use k256::elliptic_curve::{
-      subtle::{Choice, CtOption, ConstantTimeEq, ConstantTimeLess, ConditionallySelectable},
-      rand_core::RngCore,
-      bigint::{Integer, NonZero, Encoding, impl_modulus},
-      group::ff::{
-        Field, PrimeField, FieldBits, PrimeFieldBits, FromUniformBytes, helpers::sqrt_ratio_generic,
-      },
-    };
-
-    use $crate::backend::u8_from_bool;
-
-    fn reduce(x: U512) -> U256 {
-      U256::from_le_slice(&x.rem(&NonZero::new($WIDE_MODULUS).unwrap()).to_le_bytes()[.. 32])
-    }
-
-    impl ConstantTimeEq for $FieldName {
-      fn ct_eq(&self, other: &Self) -> Choice {
-        self.0.ct_eq(&other.0)
-      }
-    }
-
-    impl ConditionallySelectable for $FieldName {
-      fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
-        $FieldName(Residue::conditional_select(&a.0, &b.0, choice))
-      }
-    }
-
-    math_op!($FieldName, $FieldName, Add, add, AddAssign, add_assign, |x: $ResidueType, y| x
-      .add(&y));
-    math_op!($FieldName, $FieldName, Sub, sub, SubAssign, sub_assign, |x: $ResidueType, y| x
-      .sub(&y));
-    math_op!($FieldName, $FieldName, Mul, mul, MulAssign, mul_assign, |x: $ResidueType, y| x
-      .mul(&y));
-
-    from_wrapper!($FieldName, U256, u8);
-    from_wrapper!($FieldName, U256, u16);
-    from_wrapper!($FieldName, U256, u32);
-    from_wrapper!($FieldName, U256, u64);
-    from_wrapper!($FieldName, U256, u128);
-
-    impl Neg for $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> $FieldName {
-        Self(self.0.neg())
-      }
-    }
-
-    impl<'a> Neg for &'a $FieldName {
-      type Output = $FieldName;
-      fn neg(self) -> Self::Output {
-        (*self).neg()
-      }
-    }
-
-    impl $FieldName {
-      /// Perform an exponentation.
-      pub fn pow(&self, other: $FieldName) -> $FieldName {
-        let mut table = [Self(Residue::ONE); 16];
-        table[1] = *self;
-        for i in 2 .. 16 {
-          table[i] = table[i - 1] * self;
-        }
-
-        let mut res = Self(Residue::ONE);
-        let mut bits = 0;
-        for (i, mut bit) in other.to_le_bits().iter_mut().rev().enumerate() {
-          bits <<= 1;
-          let mut bit = u8_from_bool(bit.deref_mut());
-          bits |= bit;
-          bit.zeroize();
-
-          if ((i + 1) % 4) == 0 {
-            if i != 3 {
-              for _ in 0 .. 4 {
-                res *= res;
-              }
-            }
-
-            let mut factor = table[0];
-            for (j, candidate) in table[1 ..].iter().enumerate() {
-              let j = j + 1;
-              factor = Self::conditional_select(&factor, &candidate, usize::from(bits).ct_eq(&j));
-            }
-            res *= factor;
-            bits = 0;
-          }
-        }
-        res
-      }
-    }
-
-    impl Field for $FieldName {
-      const ZERO: Self = Self(Residue::ZERO);
-      const ONE: Self = Self(Residue::ONE);
-
-      fn random(mut rng: impl RngCore) -> Self {
-        let mut bytes = [0; 64];
-        rng.fill_bytes(&mut bytes);
-        $FieldName(Residue::new(&reduce(U512::from_be_slice(bytes.as_ref()))))
-      }
-
-      fn square(&self) -> Self {
-        Self(self.0.square())
-      }
-      fn double(&self) -> Self {
-        *self + self
-      }
-
-      fn invert(&self) -> CtOption<Self> {
-        let res = self.0.invert();
-        CtOption::new(Self(res.0), res.1.into())
-      }
-
-      fn sqrt(&self) -> CtOption<Self> {
-        // (p + 1) // 4, as valid since p % 4 == 3
-        let mod_plus_one_div_four = $MODULUS.saturating_add(&U256::ONE).wrapping_div(&(4u8.into()));
-        let res = self.pow(Self($ResidueType::new_checked(&mod_plus_one_div_four).unwrap()));
-        CtOption::new(res, res.square().ct_eq(self))
-      }
-
-      fn sqrt_ratio(num: &Self, div: &Self) -> (Choice, Self) {
-        sqrt_ratio_generic(num, div)
-      }
-    }
-
-    impl PrimeField for $FieldName {
-      type Repr = [u8; 32];
-
-      const MODULUS: &'static str = $MODULUS_STR;
-
-      const NUM_BITS: u32 = $NUM_BITS;
-      const CAPACITY: u32 = $NUM_BITS - 1;
-
-      const TWO_INV: Self = $FieldName($ResidueType::new(&U256::from_u8(2)).invert().0);
-
-      const MULTIPLICATIVE_GENERATOR: Self =
-        Self(Residue::new(&U256::from_u8($MULTIPLICATIVE_GENERATOR)));
-      const S: u32 = $S;
-
-      const ROOT_OF_UNITY: Self = $FieldName(Residue::new(&U256::from_be_hex($ROOT_OF_UNITY)));
-      const ROOT_OF_UNITY_INV: Self = Self(Self::ROOT_OF_UNITY.0.invert().0);
-
-      const DELTA: Self = $FieldName(Residue::new(&U256::from_be_hex($DELTA)));
-
-      fn from_repr(bytes: Self::Repr) -> CtOption<Self> {
-        let res = U256::from_be_slice(&bytes);
-        CtOption::new($FieldName(Residue::new(&res)), res.ct_lt(&$MODULUS))
-      }
-      fn to_repr(&self) -> Self::Repr {
-        let mut repr = [0; 32];
-        repr.copy_from_slice(&self.0.retrieve().to_be_bytes());
-        repr
-      }
-
-      fn is_odd(&self) -> Choice {
-        self.0.retrieve().is_odd()
-      }
-    }
-
-    impl PrimeFieldBits for $FieldName {
-      type ReprBits = [u8; 32];
-
-      fn to_le_bits(&self) -> FieldBits<Self::ReprBits> {
-        let mut repr = [0; 32];
-        repr.copy_from_slice(&self.0.retrieve().to_le_bytes());
-        repr.into()
-      }
-
-      fn char_le_bits() -> FieldBits<Self::ReprBits> {
-        let mut repr = [0; 32];
-        repr.copy_from_slice(&MODULUS.to_le_bytes());
-        repr.into()
-      }
-    }
-
-    impl FromUniformBytes<64> for $FieldName {
-      fn from_uniform_bytes(bytes: &[u8; 64]) -> Self {
-        $FieldName(Residue::new(&reduce(U512::from_le_slice(bytes))))
-      }
-    }
-
-    impl Sum<$FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ZERO;
-        for item in iter {
-          res += item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Sum<&'a $FieldName> for $FieldName {
-      fn sum<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().sum()
-      }
-    }
-
-    impl Product<$FieldName> for $FieldName {
-      fn product<I: Iterator<Item = $FieldName>>(iter: I) -> $FieldName {
-        let mut res = $FieldName::ONE;
-        for item in iter {
-          res *= item;
-        }
-        res
-      }
-    }
-
-    impl<'a> Product<&'a $FieldName> for $FieldName {
-      fn product<I: Iterator<Item = &'a $FieldName>>(iter: I) -> $FieldName {
-        iter.cloned().product()
-      }
-    }
-  };
-}

crypto/evrf/secq256k1/src/lib.rs

@@ -10,20 +10,39 @@ use std_shims::io::{self, Read};
 use k256::elliptic_curve::{
   zeroize::Zeroize,
   generic_array::typenum::{Sum, Diff, Quot, U, U1, U2},
-  group::{ff::PrimeField, Group},
+  group::{
+    ff::{PrimeField, FromUniformBytes},
+    Group,
+  },
 };
 
-#[macro_use]
+prime_field::odd_prime_field!(
-mod backend;
+  Scalar,
-
+  "fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f",
-mod scalar;
+  "03",
-pub use scalar::Scalar;
+  true
+);
 
 pub use k256::Scalar as FieldElement;
 
 mod point;
 pub use point::Point;
 
+pub(crate) fn u8_from_bool(bit_ref: &mut bool) -> u8 {
+  use core::hint::black_box;
+  use prime_field::zeroize::Zeroize;
+
+  let bit_ref = black_box(bit_ref);
+
+  let mut bit = black_box(*bit_ref);
+  let res = black_box(u8::from(bit));
+  bit.zeroize();
+  debug_assert!((res | 1) == 1);
+
+  bit_ref.zeroize();
+  res
+}
+
 /// Ciphersuite for Secq256k1.
 ///
 /// hash_to_F is implemented with a naive concatenation of the dst and data, allowing transposition
@@ -47,7 +66,9 @@ impl ciphersuite::Ciphersuite for Secq256k1 {
 
   fn hash_to_F(dst: &[u8], data: &[u8]) -> Self::F {
     use blake2::Digest;
-    Scalar::wide_reduce(Self::H::digest([dst, data].concat()).as_slice().try_into().unwrap())
+    <Scalar as FromUniformBytes<64>>::from_uniform_bytes(
+      &Self::H::digest([dst, data].concat()).into(),
+    )
   }
 
   // We override the provided impl, which compares against the reserialization, because

crypto/evrf/secq256k1/src/point.rs

@@ -15,7 +15,7 @@ use k256::elliptic_curve::{
   },
 };
 
-use crate::{backend::u8_from_bool, Scalar, FieldElement};
+use crate::{u8_from_bool, Scalar, FieldElement};
 
 fn recover_y(x: FieldElement) -> CtOption<FieldElement> {
   // x**3 + B since a = 0

crypto/evrf/secq256k1/src/scalar.rs

@@ -1,53 +0,0 @@
-use k256::elliptic_curve::{
-  zeroize::{DefaultIsZeroes, Zeroize},
-  bigint::{
-    U256, U512,
-    modular::constant_mod::{ResidueParams, Residue},
-  },
-};
-
-const MODULUS_STR: &str = "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F";
-
-impl_modulus!(SecQ, U256, MODULUS_STR);
-type ResidueType = Residue<SecQ, { SecQ::LIMBS }>;
-
-/// The Scalar field of secq256k1.
-///
-/// This is equivalent to the field secp256k1 is defined over.
-#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
-#[repr(C)]
-pub struct Scalar(pub(crate) ResidueType);
-
-impl DefaultIsZeroes for Scalar {}
-
-pub(crate) const MODULUS: U256 = U256::from_be_hex(MODULUS_STR);
-
-const WIDE_MODULUS: U512 = U512::from_be_hex(concat!(
-  "0000000000000000000000000000000000000000000000000000000000000000",
-  "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F",
-));
-
-field!(
-  Scalar,
-  ResidueType,
-  MODULUS_STR,
-  MODULUS,
-  WIDE_MODULUS,
-  256,
-  3,
-  1,
-  "fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2e",
-  "0000000000000000000000000000000000000000000000000000000000000009",
-);
-
-impl Scalar {
-  /// Perform a wide reduction, presumably to obtain a non-biased Scalar field element.
-  pub fn wide_reduce(bytes: [u8; 64]) -> Scalar {
-    Scalar(Residue::new(&reduce(U512::from_le_slice(bytes.as_ref()))))
-  }
-}
-
-#[test]
-fn test_scalar_field() {
-  ff_group_tests::prime_field::test_prime_field_bits::<_, Scalar>(&mut rand_core::OsRng);
-}

crypto/frost/src/curve/ed448.rs

@@ -2,7 +2,10 @@ use digest::Digest;
 
 use minimal_ed448::{Scalar, Point};
 pub use minimal_ed448::Ed448;
-pub use ciphersuite::{group::GroupEncoding, Ciphersuite};
+pub use ciphersuite::{
+  group::{ff::FromUniformBytes, GroupEncoding},
+  Ciphersuite,
+};
 
 use crate::{curve::Curve, algorithm::Hram};
 
@@ -18,7 +21,8 @@ pub(crate) struct Ietf8032Ed448Hram;
 impl Ietf8032Ed448Hram {
   #[allow(non_snake_case)]
   pub(crate) fn hram(context: &[u8], R: &Point, A: &Point, m: &[u8]) -> Scalar {
-    Scalar::wide_reduce(
+    Scalar::from_uniform_bytes(
+      &<[u8; 114]>::try_from(
         <Ed448 as Ciphersuite>::H::digest(
           [
             &[b"SigEd448".as_ref(), &[0, u8::try_from(context.len()).unwrap()]].concat(),
@@ -27,8 +31,8 @@ impl Ietf8032Ed448Hram {
           ]
           .concat(),
         )
-      .as_ref()
+        .as_slice(),
-      .try_into()
+      )
       .unwrap(),
     )
   }

crypto/prime-field/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "prime-field"
+version = "0.1.0"
+description = "A library to declare an ff::PrimeField via crypto-bigint"
+license = "MIT"
+repository = "https://github.com/serai-dex/serai/tree/develop/crypto/prime-field"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = ["ff", "field", "prime", "crypto-bigint"]
+edition = "2021"
+rust-version = "1.86"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[dependencies]
+paste = { version = "1", default-features = false }
+zeroize = { version = "^1.5", default-features = false }
+subtle = { version = "^2.4", default-features = false }
+rand_core = { version = "0.6", default-features = false }
+
+crypto-bigint = { version = "0.6", default-features = false, features = ["zeroize"] }
+
+ff = { version = "0.13", default-features = false, features = ["bits"] }
+
+ff-group-tests = { version = "0.13", path = "../ff-group-tests", optional = true }
+
+[features]
+alloc = ["zeroize/alloc", "crypto-bigint/alloc", "ff/alloc"]
+std = ["zeroize/std", "subtle/std", "rand_core/std", "ff/std", "ff-group-tests"]
+default = ["std"]

crypto/prime-field/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022-2025 Luke Parker
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

crypto/prime-field/README.md

@@ -0,0 +1,3 @@
+# Prime Field
+
+A comprehensive macro to declare a prime field.

crypto/prime-field/src/lib.rs

@@ -0,0 +1,521 @@
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![doc = include_str!("../README.md")]
+#![no_std]
+
+pub use subtle;
+pub use zeroize;
+pub use rand_core;
+pub use crypto_bigint;
+pub use ff;
+
+#[doc(hidden)]
+pub mod __prime_field_private {
+  pub use paste;
+  pub use ff_group_tests;
+
+  use crypto_bigint::{Word, Uint, modular::ConstMontyParams};
+
+  /// Remove the "0x"-prefix from a hex string.
+  ///
+  /// May panic if the string isn't valid hex.
+  pub const fn hex_str_without_prefix(hex: &str) -> &str {
+    if hex.len() < 2 {
+      return hex;
+    }
+
+    if hex.as_bytes()[1] == b'x' {
+      assert!(hex.as_bytes()[0] == b'0', "invalid hex string for modulus");
+      hex.split_at(2).1
+    } else {
+      hex
+    }
+  }
+
+  pub const fn uint_to_u64_words<const LIMBS: usize, const WORDS: usize>(
+    value: Uint<LIMBS>,
+  ) -> [u64; WORDS] {
+    let mut res = [0u64; WORDS];
+    let mut i = 0;
+    while i < Uint::<LIMBS>::LIMBS {
+      let word: Word = value.as_limbs()[i].0;
+      let bits = i * (Word::BITS as usize);
+      let j = bits / (u64::BITS as usize);
+      res[j] |= word << (bits % (u64::BITS as usize));
+      if (j + 1) < WORDS {
+        if let Some(remaining_bits) =
+          ((bits % (u64::BITS as usize)) + (Word::BITS as usize)).checked_sub(u64::BITS as usize)
+        {
+          if remaining_bits != 0 {
+            res[j + 1] |= word >> ((Word::BITS as usize) - remaining_bits);
+          }
+        }
+      }
+      i += 1;
+    }
+    res
+  }
+
+  pub const fn u64_words_to_uint<const LIMBS: usize, const WORDS: usize>(
+    words: [u64; WORDS],
+  ) -> Uint<LIMBS> {
+    let mut reconstruction = Uint::<LIMBS>::ZERO;
+    let mut i = 0;
+    while i < WORDS {
+      reconstruction = reconstruction
+        .bitor(&Uint::<LIMBS>::from_u64(words[i]).shl_vartime((i * (u64::BITS as usize)) as u32));
+      i += 1;
+    }
+    reconstruction
+  }
+
+  #[allow(non_snake_case)]
+  pub const fn calculate_S<const LIMBS: usize, P: ConstMontyParams<LIMBS>>() -> u32 {
+    let mut i = 0;
+    loop {
+      let bit = P::MODULUS.as_ref().wrapping_sub(&Uint::<LIMBS>::ONE).bit_vartime(i);
+      if !bit {
+        i += 1;
+        continue;
+      }
+      break;
+    }
+    i
+  }
+}
+
+#[macro_export]
+macro_rules! odd_prime_field {
+  (
+    $name: ident,
+    $modulus_as_be_hex: expr,
+    $multiplicative_generator_as_be_hex: expr,
+    $big_endian: literal
+  ) => {
+    prime_field::__prime_field_private::paste::paste! {
+      mod [<$name __prime_field_private>] {
+        use core::{
+          ops::*,
+          iter::{Sum, Product},
+        };
+        use prime_field::{
+          subtle::{
+            Choice, CtOption, ConstantTimeEq, ConditionallySelectable, ConditionallyNegatable,
+          },
+          zeroize::Zeroize,
+          rand_core::RngCore,
+          crypto_bigint::{
+            Limb, Encoding, Integer, Uint,
+            modular::{ConstMontyParams, ConstMontyForm},
+            impl_modulus,
+          },
+          ff::*,
+          __prime_field_private::*,
+        };
+
+        const MODULUS_WITHOUT_PREFIX: &str = hex_str_without_prefix($modulus_as_be_hex);
+        const MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX: &str =
+          hex_str_without_prefix($multiplicative_generator_as_be_hex);
+
+        const MODULUS_BYTES: usize = MODULUS_WITHOUT_PREFIX.len() / 2;
+        type UnderlyingUint = Uint<{ MODULUS_BYTES.div_ceil(Limb::BYTES) }>;
+
+        const PADDED_MODULUS_WITHOUT_PREFIX_BYTES: [u8; 2 * UnderlyingUint::BYTES] = {
+          let mut res = [b'0'; 2 * UnderlyingUint::BYTES];
+          let start = (2 * UnderlyingUint::BYTES) - MODULUS_WITHOUT_PREFIX.len();
+          let mut i = start;
+          while i < (2 * UnderlyingUint::BYTES) {
+            res[i] = MODULUS_WITHOUT_PREFIX.as_bytes()[i - start];
+            i += 1;
+          }
+          res
+        };
+        const PADDED_MODULUS_WITHOUT_PREFIX: &str = {
+          match core::str::from_utf8(&PADDED_MODULUS_WITHOUT_PREFIX_BYTES) {
+            Ok(res) => res,
+            Err(_) => panic!("couldn't successfully pad modulus"),
+          }
+        };
+
+        const PADDED_MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX_BYTES:
+          [u8; 2 * UnderlyingUint::BYTES] = {
+          let mut res = [b'0'; 2 * UnderlyingUint::BYTES];
+          let start = (2 * UnderlyingUint::BYTES) - MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX.len();
+          let mut i = start;
+          while i < (2 * UnderlyingUint::BYTES) {
+            res[i] = MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX.as_bytes()[i - start];
+            i += 1;
+          }
+          res
+        };
+        const PADDED_MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX: &str = {
+          match core::str::from_utf8(&PADDED_MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX_BYTES) {
+            Ok(res) => res,
+            Err(_) => panic!("couldn't successfully pad multiplicative generator"),
+          }
+        };
+
+        impl_modulus!(Params, UnderlyingUint, PADDED_MODULUS_WITHOUT_PREFIX);
+        type Underlying = ConstMontyForm<Params, { UnderlyingUint::LIMBS }>;
+
+        const MODULUS: &UnderlyingUint = Params::MODULUS.as_ref();
+        const MODULUS_MINUS_ONE: UnderlyingUint = MODULUS.wrapping_sub(&UnderlyingUint::ONE);
+        const MODULUS_MINUS_TWO: UnderlyingUint = MODULUS.wrapping_sub(&UnderlyingUint::from_u8(2));
+        const T: UnderlyingUint = MODULUS_MINUS_ONE.shr_vartime($name::S);
+
+        /// A field automatically generated with `short-weierstrass`.
+        #[derive(Clone, Copy, Eq, Debug)]
+        pub struct $name(Underlying);
+
+        impl Default for $name {
+          fn default() -> Self {
+            Self::ZERO
+          }
+        }
+
+        impl $name {
+          /// Create a `$name` from the `Uint` type underlying it.
+          pub const fn from(value: &UnderlyingUint) -> Self {
+            $name(Underlying::new(value))
+          }
+        }
+        impl From<u8> for $name {
+          fn from(value: u8) -> Self {
+            Self::from(&UnderlyingUint::from(value))
+          }
+        }
+        impl From<u16> for $name {
+          fn from(value: u16) -> Self {
+            Self::from(&UnderlyingUint::from(value))
+          }
+        }
+        impl From<u32> for $name {
+          fn from(value: u32) -> Self {
+            Self::from(&UnderlyingUint::from(value))
+          }
+        }
+        impl From<u64> for $name {
+          fn from(value: u64) -> Self {
+            Self::from(&UnderlyingUint::from(value))
+          }
+        }
+
+        impl ConstantTimeEq for $name {
+          fn ct_eq(&self, other: &Self) -> Choice {
+            self.0.ct_eq(&other.0)
+          }
+        }
+        impl PartialEq for $name {
+          fn eq(&self, other: &Self) -> bool {
+            bool::from(self.ct_eq(other))
+          }
+        }
+
+        impl ConditionallySelectable for $name {
+          fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
+            Self(<_>::conditional_select(&a.0, &b.0, choice))
+          }
+        }
+        impl ConditionallyNegatable for $name {
+          fn conditional_negate(&mut self, negate: Choice) {
+            self.0.conditional_negate(negate)
+          }
+        }
+
+        impl Zeroize for $name {
+          fn zeroize(&mut self) {
+            self.0.zeroize();
+          }
+        }
+
+        impl Neg for $name {
+          type Output = Self;
+          fn neg(self) -> Self {
+            Self(-self.0)
+          }
+        }
+
+        impl Add for $name {
+          type Output = Self;
+          fn add(self, other: Self) -> Self {
+            Self(self.0 + other.0)
+          }
+        }
+        impl Sub for $name {
+          type Output = Self;
+          fn sub(self, other: Self) -> Self {
+            Self(self.0 - other.0)
+          }
+        }
+        impl Mul for $name {
+          type Output = Self;
+          fn mul(self, other: Self) -> Self {
+            Self(self.0 * other.0)
+          }
+        }
+        impl AddAssign for $name {
+          fn add_assign(&mut self, other: Self) {
+            self.0 += other.0;
+          }
+        }
+        impl SubAssign for $name {
+          fn sub_assign(&mut self, other: Self) {
+            self.0 -= other.0;
+          }
+        }
+        impl MulAssign for $name {
+          fn mul_assign(&mut self, other: Self) {
+            self.0 *= other.0;
+          }
+        }
+        impl Sum for $name {
+          fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
+            let mut res = Self::ZERO;
+            for item in iter {
+              res += item;
+            }
+            res
+          }
+        }
+        impl Product for $name {
+          fn product<I: Iterator<Item = Self>>(iter: I) -> Self {
+            let mut res = Self::ONE;
+            for item in iter {
+              res *= item;
+            }
+            res
+          }
+        }
+        impl<'a> Add<&'a Self> for $name {
+          type Output = Self;
+          fn add(self, other: &'a Self) -> Self {
+            Self(self.0 + other.0)
+          }
+        }
+        impl<'a> Sub<&'a Self> for $name {
+          type Output = Self;
+          fn sub(self, other: &'a Self) -> Self {
+            Self(self.0 - other.0)
+          }
+        }
+        impl<'a> Mul<&'a Self> for $name {
+          type Output = Self;
+          fn mul(self, other: &'a Self) -> Self {
+            Self(self.0 * other.0)
+          }
+        }
+        impl<'a> Sum<&'a Self> for $name {
+          fn sum<I: Iterator<Item = &'a Self>>(iter: I) -> Self {
+            let mut res = Self::ZERO;
+            for item in iter {
+              res += item;
+            }
+            res
+          }
+        }
+        impl<'a> Product<&'a Self> for $name {
+          fn product<I: Iterator<Item = &'a Self>>(iter: I) -> Self {
+            let mut res = Self::ONE;
+            for item in iter {
+              res *= item;
+            }
+            res
+          }
+        }
+        impl<'a> AddAssign<&'a Self> for $name {
+          fn add_assign(&mut self, other: &'a Self) {
+            self.0 += other.0;
+          }
+        }
+        impl<'a> SubAssign<&'a Self> for $name {
+          fn sub_assign(&mut self, other: &'a Self) {
+            self.0 -= other.0;
+          }
+        }
+        impl<'a> MulAssign<&'a Self> for $name {
+          fn mul_assign(&mut self, other: &'a Self) {
+            self.0 *= other.0;
+          }
+        }
+
+        impl Field for $name {
+          const ZERO: Self = Self(Underlying::ZERO);
+          const ONE: Self = Self(Underlying::ONE);
+          fn random(mut rng: impl RngCore) -> Self {
+            let mut bytes = [0; 2 * MODULUS_BYTES];
+            rng.fill_bytes(&mut bytes);
+            Self::from_uniform_bytes(&bytes)
+          }
+          fn square(&self) -> Self {
+            Self(self.0.square())
+          }
+          fn double(&self) -> Self {
+            Self(self.0.double())
+          }
+          fn invert(&self) -> CtOption<Self> {
+            CtOption::from(self.0.inv()).map(Self)
+          }
+          fn sqrt(&self) -> CtOption<Self> {
+            const THREE_MOD_FOUR: bool = (MODULUS.as_words()[0] % 4) == 3;
+            const ONE_MOD_EIGHT: bool = (MODULUS.as_words()[0] % 8) == 1;
+            const FIVE_MOD_EIGHT: bool = (MODULUS.as_words()[0] % 8) == 5;
+
+            let sqrt = if THREE_MOD_FOUR {
+              const SQRT_EXP: UnderlyingUint =
+                MODULUS.shr_vartime(2).wrapping_add(&UnderlyingUint::ONE);
+              Self(self.0.pow(&SQRT_EXP))
+            } else if ONE_MOD_EIGHT {
+              const TM1D2: UnderlyingUint = (T.wrapping_sub(&UnderlyingUint::ONE)).shr_vartime(1);
+              const TM1D2_WORDS_LEN: usize = UnderlyingUint::BITS.div_ceil(u64::BITS) as usize;
+              const TM1D2_WORDS: [u64; TM1D2_WORDS_LEN] = uint_to_u64_words(TM1D2);
+
+              const TM1D2_RECONSTRUCTION: UnderlyingUint = u64_words_to_uint(TM1D2_WORDS);
+              const RECONSTRUCTION_EQUALS_VALUE: bool = {
+                let mut i = 0;
+                let mut res = true;
+                while i < TM1D2_WORDS_LEN {
+                  res &= TM1D2_RECONSTRUCTION.as_words()[i] == TM1D2.as_words()[i];
+                  i += 1;
+                }
+                res
+              };
+              const _ASSERT_RECONSTRUCTION_EQUALS_VALUE:
+                [(); 0 - ((!RECONSTRUCTION_EQUALS_VALUE) as usize)] = [(); _];
+
+              helpers::sqrt_tonelli_shanks::<Self, _>(self, TM1D2_WORDS).unwrap_or(Self::ZERO)
+            } else {
+              const SQRT_EXP: UnderlyingUint = MODULUS.shr_vartime(3);
+              let upsilon = self.double().0.pow(&SQRT_EXP);
+              let i = (upsilon.square() * &self.0).double();
+              Self(upsilon * self.0 * (i - Self::ONE.0))
+            };
+
+            let sqrt = <_>::conditional_select(&sqrt, &-sqrt, sqrt.0.retrieve().is_odd());
+            CtOption::new(sqrt, sqrt.square().ct_eq(self))
+          }
+          fn sqrt_ratio(num: &Self, div: &Self) -> (Choice, Self) {
+            helpers::sqrt_ratio_generic(num, div)
+          }
+        }
+
+        #[derive(Clone, Copy)]
+        pub struct Repr([u8; MODULUS_BYTES]);
+        impl Default for Repr {
+          fn default() -> Self {
+            Self([0; _])
+          }
+        }
+        impl AsRef<[u8]> for Repr {
+          fn as_ref(&self) -> &[u8] {
+            self.0.as_ref()
+          }
+        }
+        impl AsMut<[u8]> for Repr {
+          fn as_mut(&mut self) -> &mut [u8] {
+            self.0.as_mut()
+          }
+        }
+
+        impl PrimeField for $name {
+          type Repr = Repr;
+          const MODULUS: &str = $modulus_as_be_hex;
+          const NUM_BITS: u32 = MODULUS.bits();
+          const CAPACITY: u32 = Self::NUM_BITS - 1;
+          const TWO_INV: Self =
+            Self(Underlying::new(&UnderlyingUint::from_u8(2)).pow(&MODULUS_MINUS_TWO));
+          const MULTIPLICATIVE_GENERATOR: Self = Self(
+            Underlying::new(
+              &UnderlyingUint::from_be_hex(PADDED_MULTIPLICATIVE_GENERATOR_WITHOUT_PREFIX)
+            )
+          );
+          const S: u32 = calculate_S::<_, Params>();
+          const ROOT_OF_UNITY: Self = Self(Self::MULTIPLICATIVE_GENERATOR.0.pow(&T));
+          const ROOT_OF_UNITY_INV: Self = Self(Self::ROOT_OF_UNITY.0.pow(&MODULUS_MINUS_TWO));
+          const DELTA: Self = {
+            let two_to_the_s = UnderlyingUint::ONE.shl_vartime(Self::S);
+            Self(Self::MULTIPLICATIVE_GENERATOR.0.pow(&two_to_the_s))
+          };
+
+          fn to_repr(&self) -> Self::Repr {
+            let mut res = Repr([0; _]);
+            if $big_endian {
+              res.0.copy_from_slice(
+                &self.0.retrieve().to_be_bytes()[(UnderlyingUint::BYTES - MODULUS_BYTES) ..]
+              );
+            } else {
+              res.0.copy_from_slice(&self.0.retrieve().to_le_bytes()[.. MODULUS_BYTES]);
+            }
+            res
+          }
+          fn from_repr(repr: Self::Repr) -> CtOption<Self> {
+            let mut expanded_repr = [0; UnderlyingUint::BYTES];
+            let result = Self(if $big_endian {
+              expanded_repr[(UnderlyingUint::BYTES - MODULUS_BYTES) .. ].copy_from_slice(&repr.0);
+              Underlying::new(&UnderlyingUint::from_be_bytes(expanded_repr))
+            } else {
+              expanded_repr[.. MODULUS_BYTES].copy_from_slice(&repr.0);
+              Underlying::new(&UnderlyingUint::from_le_bytes(expanded_repr))
+            });
+            CtOption::new(result, result.to_repr().0.ct_eq(&repr.0))
+          }
+          fn is_odd(&self) -> Choice {
+            self.0.retrieve().is_odd()
+          }
+        }
+
+        impl PrimeFieldBits for $name {
+          type ReprBits = [u8; UnderlyingUint::BYTES];
+          fn to_le_bits(&self) -> FieldBits<Self::ReprBits> {
+            self.0.retrieve().to_le_bytes().into()
+          }
+          fn char_le_bits() -> FieldBits<Self::ReprBits> {
+            MODULUS.to_le_bytes().into()
+          }
+        }
+
+        impl FromUniformBytes<{ 2 * MODULUS_BYTES }> for $name {
+          fn from_uniform_bytes(bytes: &[u8; 2 * MODULUS_BYTES]) -> Self {
+            let mut expanded_wide_repr = [0; 2 * UnderlyingUint::BYTES];
+            expanded_wide_repr[.. (2 * MODULUS_BYTES)].copy_from_slice(bytes);
+            let bytes = expanded_wide_repr;
+
+            let lo =
+              Underlying::new(&UnderlyingUint::from_le_slice(&bytes[.. UnderlyingUint::BYTES]));
+            let hi =
+              Underlying::new(&UnderlyingUint::from_le_slice(&bytes[UnderlyingUint::BYTES ..]));
+            const HI: Underlying = {
+              let mut res = Underlying::new(&UnderlyingUint::ONE);
+              let mut i = 0;
+              while i < UnderlyingUint::BITS {
+                res = res.double();
+                i += 1;
+              }
+              res
+            };
+            Self(lo + (hi * HI))
+          }
+        }
+
+        const BITS_PLUS_SECURITY_LEVEL: usize =
+          (MODULUS.bits() + MODULUS.bits().div_ceil(2)) as usize;
+        const BITS_PLUS_SECURITY_LEVEL_BYTES: usize = BITS_PLUS_SECURITY_LEVEL.div_ceil(8);
+        impl FromUniformBytes<{ BITS_PLUS_SECURITY_LEVEL_BYTES }> for $name {
+          fn from_uniform_bytes(bytes: &[u8; BITS_PLUS_SECURITY_LEVEL_BYTES]) -> Self {
+            let mut larger = [0; 2 * MODULUS_BYTES];
+            larger[.. BITS_PLUS_SECURITY_LEVEL_BYTES].copy_from_slice(bytes);
+            Self::from_uniform_bytes(&larger)
+          }
+        }
+
+        #[cfg(feature = "std")]
+        #[test]
+        fn test() {
+          use prime_field::__prime_field_private::ff_group_tests;
+          use ff_group_tests::prime_field::test_prime_field_bits;
+          test_prime_field_bits::<_, $name>(&mut prime_field::rand_core::OsRng);
+        }
+      }
+
+      pub use [<$name __prime_field_private>]::$name;
+    }
+  };
+}

crypto/prime-field/tests/5mod8.rs

@@ -0,0 +1,6 @@
+prime_field::odd_prime_field!(
+  Scalar,
+  "0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed",
+  "02",
+  false
+);

orchestration/src/main.rs

@@ -309,12 +309,12 @@ fn embedded_curve_keys(network: Network) -> EmbeddedCurveKeys {
     embedwards25519: {
       let key = Zeroizing::new(<Embedwards25519 as Ciphersuite>::F::random(&mut rng));
       let pub_key = Embedwards25519::generator() * key.deref();
-      (Zeroizing::new(key.to_repr().as_slice().to_vec()), pub_key.to_bytes().to_vec())
+      (Zeroizing::new(key.to_repr().as_ref().to_vec()), pub_key.to_bytes().to_vec())
     },
     secq256k1: {
       let key = Zeroizing::new(<Secq256k1 as Ciphersuite>::F::random(&mut rng));
       let pub_key = Secq256k1::generator() * key.deref();
-      (Zeroizing::new(key.to_repr().as_slice().to_vec()), pub_key.to_bytes().to_vec())
+      (Zeroizing::new(key.to_repr().as_ref().to_vec()), pub_key.to_bytes().to_vec())
     },
   }
 }

tests/no-std/Cargo.toml

@@ -28,6 +28,7 @@ multiexp = { path = "../../crypto/multiexp", default-features = false, features
 
 schnorr-signatures = { path = "../../crypto/schnorr", default-features = false }
 
+prime-field = { path = "../../crypto/prime-field", default-features = false, features = ["alloc"] }
 secq256k1 = { path = "../../crypto/evrf/secq256k1", default-features = false }
 embedwards25519 = { path = "../../crypto/evrf/embedwards25519", default-features = false }
 

tests/no-std/src/lib.rs

@@ -11,6 +11,7 @@ pub use multiexp;
 
 pub use schnorr_signatures;
 
+pub use prime_field;
 pub use secq256k1;
 pub use embedwards25519;