Self-review cleanup and tweaks

synedrion/src/cggmp21/conversion.rs

@@ -28,9 +28,7 @@ fn uint_from_scalar<P: SchemeParams>(value: &Scalar<P>) -> <P::Paillier as Paill
 pub(crate) fn public_signed_from_scalar<P: SchemeParams>(
     value: &Scalar<P>,
 ) -> PublicSigned<<P::Paillier as PaillierParams>::Uint> {
-    // TODO: When elliptic-curve upgrades to crypto-bigint v0.6 the Integer trait will implement
-    // BitOps so we can do `P::CURVE_ORDER.bits_vartime()` directly I reckon.
-    let order_bits = BitOps::bits_vartime(&P::CURVE_ORDER.get());
+    let order_bits = P::CURVE_ORDER.as_ref().bits_vartime();
     PublicSigned::new_positive(uint_from_scalar::<P>(value), order_bits).expect(concat![
         "a curve scalar value is smaller than the half of `PaillierParams::Uint` range, ",
         "so it is still positive when treated as a 2-complement signed value"

synedrion/src/cggmp21/entities.rs

@@ -112,7 +112,7 @@ pub(crate) struct PublicAuxInfoPrecomputed<P: SchemeParams> {
 pub struct KeyShareChange<P: SchemeParams, I: Ord> {
     pub(crate) owner: I,
     /// The value to be added to the secret share.
-    pub(crate) secret_share_change: Secret<Scalar<P>>,
+    pub(crate) secret_share_change: Secret<Scalar<P>>, // `x_i^* - x_i == \sum_{j} x_j^i`
     /// The values to be added to the public shares of remote nodes.
     pub(crate) public_share_changes: BTreeMap<I, Point<P>>, // `X_k^* - X_k == \sum_j X_j^k`, for all nodes
 }

synedrion/src/cggmp21/interactive_signing.rs

@@ -45,7 +45,7 @@ use crate::{
 };
 
 /// Prehashed message to sign.
-// TODO: Type aliases are not enforced by the compiler, but it should be. Maybe one day it will?
+// TODO: Type aliases are not enforced by the compiler, but they should be. Maybe one?
 #[allow(type_alias_bounds)]
 pub type PrehashedMessage<C: Curve> = FieldBytes<C>;
 

synedrion/src/cggmp21/params.rs

@@ -8,7 +8,7 @@ use crypto_bigint::{BitOps, NonZero, Uint, U1024, U2048, U4096, U512, U8192};
 use digest::generic_array::{ArrayLength, GenericArray};
 use ecdsa::hazmat::{DigestPrimitive, SignPrimitive, VerifyPrimitive};
 use primeorder::elliptic_curve::{
-    bigint::{Concat, Uint as CurveUint},
+    bigint::{self as bigintv05, Concat, Uint as CurveUint},
     point::DecompressPoint,
     sec1::{FromEncodedPoint, ModulusSize, ToEncodedPoint},
     Curve, CurveArithmetic, PrimeCurve,
@@ -132,8 +132,7 @@ where
     /// The elliptic curve (of prime order) used.
     type Curve: CurveArithmetic + PrimeCurve + HashableType + DigestPrimitive;
     /// Double the curve Scalar-width integer type.
-    type WideCurveUint: primeorder::elliptic_curve::bigint::Integer
-        + primeorder::elliptic_curve::bigint::Split<Output = <Self::Curve as Curve>::Uint>;
+    type WideCurveUint: bigintv05::Integer + bigintv05::Split<Output = <Self::Curve as Curve>::Uint>;
     // TODO: We should get rid of this entirely, along with the FofHasher. Instead generate a Box<[u8]> of length 2 * P::SECURITY_BITS and use that.
     /// Bla
     type HashOutput: Clone
@@ -205,7 +204,7 @@ pub struct TestParams;
 // - P^{fac} assumes $N ~ 2^{4 \ell + 2 \eps}$
 impl SchemeParams for TestParams {
     type Curve = TinyCurve64;
-    type WideCurveUint = primeorder::elliptic_curve::bigint::U384;
+    type WideCurveUint = bigintv05::U384;
     // TODO: 8*24 = 192, this is to work around an issue with the ModulusSize-trait. This should be ideally be 8 bytes long.
     type HashOutput = [u8; 24];
     const SECURITY_BITS: usize = 16;
@@ -230,7 +229,7 @@ pub struct TestParams32;
 #[cfg(test)]
 impl SchemeParams for TestParams32 {
     type Curve = TinyCurve32;
-    type WideCurveUint = primeorder::elliptic_curve::bigint::U384;
+    type WideCurveUint = bigintv05::U384;
     type HashOutput = [u8; 24];
     const SECURITY_BITS: usize = 16;
     const SECURITY_PARAMETER: usize = 10;
@@ -254,7 +253,7 @@ pub struct ProductionParams112;
 
 impl SchemeParams for ProductionParams112 {
     type Curve = k256::Secp256k1;
-    type WideCurveUint = primeorder::elliptic_curve::bigint::U512;
+    type WideCurveUint = bigintv05::U512;
     type HashOutput = [u8; 32];
     const SECURITY_BITS: usize = 112;
     const SECURITY_PARAMETER: usize = 256;
@@ -274,9 +273,10 @@ impl SchemeParams for ProductionParams112 {
 
 #[cfg(test)]
 mod tests {
-    use primeorder::elliptic_curve::bigint::{U256, U64};
-
-    use super::{upcast_uint, ProductionParams112, SchemeParams};
+    use super::{
+        bigintv05::{U256, U64},
+        upcast_uint, ProductionParams112, SchemeParams, TestParams, TestParams32,
+    };
 
     #[test]
     fn upcast_uint_results_in_a_bigger_type() {
@@ -304,5 +304,7 @@ mod tests {
     #[test]
     fn parameter_consistency() {
         assert!(ProductionParams112::are_self_consistent());
+        assert!(TestParams::are_self_consistent());
+        assert!(TestParams32::are_self_consistent());
     }
 }

synedrion/src/curve/arithmetic.rs

@@ -83,7 +83,7 @@ impl HashableType for TinyCurve32 {
 type BackendScalar<P> = <<P as SchemeParams>::Curve as CurveArithmetic>::Scalar;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Default, PartialOrd, Ord, Zeroize)]
-pub(crate) struct Scalar<P: SchemeParams>(<P::Curve as CurveArithmetic>::Scalar);
+pub(crate) struct Scalar<P: SchemeParams>(BackendScalar<P>);
 
 impl<P: SchemeParams> Scalar<P> {
     pub const ZERO: Self = Self(BackendScalar::<P>::ZERO);