Merge remote-tracking branch 'origin/master' into support-for-more-ba…

…ckends

curves/bls12_377/scripts/bls12_isogeny_computer.sage

@@ -197,7 +197,7 @@ def bls12_377_hash_to_G2(e2_p6S_iso, data):
 # e26_order = Ell2_6.order()
 # for i in primes(30):
 #     if e26_order % i == 0:
-#         print("order is divisable by ", i)
+#         print("order is divisible by ", i)
 
 def find_non_square():
     quad_non_res = 0x01ae3a4617c510eac63b05c06ca1493b1a22d9f300f5138f1ef3622fba094800170b5d44300000008508bffffffffffc

curves/bls12_381/src/curves/g2.rs

@@ -257,7 +257,7 @@ const DOUBLE_P_POWER_ENDOMORPHISM_COEFF_0: Fq2 = Fq2::new(
     Fq::ZERO
 );
 
-/// psi(P) is the untwist-Frobenius-twist endomorhism on E'(Fq2)
+/// psi(P) is the untwist-Frobenius-twist endomorphism on E'(Fq2)
 fn p_power_endomorphism(p: &Affine<Config>) -> Affine<Config> {
     // The p-power endomorphism for G2 is defined as follows:
     // 1. Note that G2 is defined on curve E': y^2 = x^3 + 4(u+1).
@@ -295,7 +295,7 @@ fn double_p_power_endomorphism(p: &Projective<Config>) -> Projective<Config> {
     res
 }
 
-// Parametres from the [IETF draft v16, section E.3](https://www.ietf.org/archive/id/draft-irtf-cfrg-hash-to-curve-16.html#name-3-isogeny-map-for-bls12-381).
+// Parameters from the [IETF draft v16, section E.3](https://www.ietf.org/archive/id/draft-irtf-cfrg-hash-to-curve-16.html#name-3-isogeny-map-for-bls12-381).
 impl WBConfig for Config {
     type IsogenousCurve = g2_swu_iso::SwuIsoConfig;
 

ec/src/hashing/curve_maps/curve_map_parameter_helper.sage

@@ -24,7 +24,7 @@ def find_z_sswu(F, A, B):
         ctr += 1
 
 # Finds the smallest z in term of non-zero bit
-# in sage representation for consturcting
+# in sage representation for constructing
 # elligator2 map for a curve defined over field F.
 # Argument:
 # - F, a field object, e.g., F = GF(2^255 - 19)

ec/src/hashing/curve_maps/elligator2.rs

@@ -264,7 +264,7 @@ mod test {
         Elligator2Map::<TestElligator2MapToCurveConfig>::check_parameters().unwrap();
 
         let mut map_range: Vec<Affine<TestElligator2MapToCurveConfig>> = vec![];
-        // We are mapping all elemnts of the field to the curve, verifying that
+        // We are mapping all elements of the field to the curve, verifying that
         // map is not constant on that set.
         for current_field_element in 0..101 {
             map_range.push(

ff/README.md

@@ -16,7 +16,7 @@ This crate contains two types of traits:
 
 The available field traits are:
 
-- [`AdditiveGroup`](/ff/src/lib.rs) - Interface for additive groups that have a "scalar multiplication" operation with respect to the `Scalar` associated type. This applies to to prime-order fields, field extensions, and elliptic-curve groups used in cryptography.
+- [`AdditiveGroup`](https://github.com/arkworks-rs/algebra/blob/master/ff/src/fields/mod.rs#L46) - Interface for additive groups that have a "scalar multiplication" operation with respect to the `Scalar` associated type. This applies to to prime-order fields, field extensions, and elliptic-curve groups used in cryptography.
 - [`Field`](https://github.com/arkworks-rs/algebra/blob/master/ff/src/fields/mod.rs#L161) - Interface for a generic finite field.
 - [`FftField`](https://github.com/arkworks-rs/algebra/blob/master/ff/src/fields/fft_friendly.rs#L2) - Exposes methods that allow for performing efficient FFTs on field elements.
 - [`PrimeField`](https://github.com/arkworks-rs/algebra/blob/master/ff/src/fields/prime.rs#L27) - Field with a prime `p` number of elements, also referred to as `Fp`.

ff/src/fields/models/fp/montgomery/mod.rs

@@ -210,7 +210,7 @@ pub trait MontConfig<const N: usize>: 'static + Sync + Send + Sized {
                     }
                     r[N - 1] = carry1 + carry2;
                 }
-                (a.0).0 = r;
+                (a.0).0.copy_from_slice(&r);
             }
             a.subtract_modulus();
         } else {
@@ -290,7 +290,7 @@ pub trait MontConfig<const N: usize>: 'static + Sync + Send + Sized {
         let mut carry2 = 0;
         for i in 0..N {
             let k = r[i].wrapping_mul(Self::INV);
-            let mut carry = 0;
+            carry = 0;
             fa::mac_discard(r[i], k, Self::MODULUS.0[0], &mut carry);
             for j in 1..N {
                 r[j + i] = fa::mac_with_carry(r[j + i], k, Self::MODULUS.0[j], &mut carry);
@@ -508,12 +508,11 @@ pub trait MontConfig<const N: usize>: 'static + Sync + Send + Sized {
 #[inline]
 pub const fn can_use_no_carry_mul_optimization<T: MontConfig<N>, const N: usize>() -> bool {
     // Checking the modulus at compile time
-    let top_bit_is_zero = T::MODULUS.0[N - 1] >> 63 == 0;
     let mut all_remaining_bits_are_one = T::MODULUS.0[N - 1] == u64::MAX >> 1;
     crate::const_for!((i in 1..N) {
         all_remaining_bits_are_one  &= T::MODULUS.0[N - i - 1] == u64::MAX;
     });
-    top_bit_is_zero && !all_remaining_bits_are_one
+    modulus_has_spare_bit::<T, N>() && !all_remaining_bits_are_one
 }
 
 #[inline]