Update curve25519-dalek to 4.0.0-rc.1 (#261)

* Update curve25519-dalek requirement from =4.0.0-pre.1 to =4.0.0-rc.1

Updates the requirements on [curve25519-dalek](https://github.com/dalek-cryptography/curve25519-dalek) to permit the latest version.
- [Release notes](https://github.com/dalek-cryptography/curve25519-dalek/releases)
- [Changelog](https://github.com/dalek-cryptography/curve25519-dalek/blob/main/CHANGELOG.md)
- [Commits](https://github.com/dalek-cryptography/curve25519-dalek/commits)

---
updated-dependencies:
- dependency-name: curve25519-dalek
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

* fix breaking curve25519-dalek changes

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frost-core/Cargo.toml

@@ -33,7 +33,7 @@ serde_json = { version = "1.0", optional = true }
 criterion = { version = "0.4", optional = true }
 
 [dev-dependencies]
-curve25519-dalek = { version = "=4.0.0-pre.1", features = ["serde"] }
+curve25519-dalek = { version = "=4.0.0-rc.1", features = ["serde"] }
 lazy_static = "1.4"
 proptest = "1.0"
 rand = "0.8"

frost-ed25519/Cargo.toml

@@ -22,7 +22,7 @@ description = "A Schnorr signature scheme over the prime-order Ristretto group t
 features = ["nightly"]
 
 [dependencies]
-curve25519-dalek = { version = "=4.0.0-pre.1", features = ["serde"] }
+curve25519-dalek = { version = "=4.0.0-rc.1", features = ["serde"] }
 frost-core = { path = "../frost-core", features = ["test-impl"] }
 frost-ristretto255 = { path = "../frost-ristretto255" }
 rand_core = "0.6"

frost-ed25519/src/lib.rs

@@ -34,7 +34,7 @@ impl Group for Ed25519Group {
     type Serialization = [u8; 32];
 
     fn cofactor() -> <Self::Field as Field>::Scalar {
-        Scalar::one()
+        Scalar::ONE
     }
 
     fn identity() -> Self::Element {
@@ -50,7 +50,10 @@ impl Group for Ed25519Group {
     }
 
     fn deserialize(buf: &Self::Serialization) -> Result<Self::Element, GroupError> {
-        match CompressedEdwardsY::from_slice(buf.as_ref()).decompress() {
+        match CompressedEdwardsY::from_slice(buf.as_ref())
+            .map_err(|_| GroupError::MalformedElement)?
+            .decompress()
+        {
             Some(point) => {
                 if point == Self::identity() {
                     Err(GroupError::InvalidIdentityElement)

frost-ristretto255/Cargo.toml

@@ -18,7 +18,7 @@ description = "A Schnorr signature scheme over the prime-order Ristretto group t
 features = ["nightly"]
 
 [dependencies]
-curve25519-dalek = { version = "=4.0.0-pre.1", features = ["serde"] }
+curve25519-dalek = { version = "=4.0.0-rc.1", features = ["serde", "rand_core"] }
 frost-core = { path = "../frost-core", features = ["test-impl"] }
 rand_core = "0.6"
 sha2 = "0.10.2"

frost-ristretto255/src/lib.rs

@@ -29,11 +29,11 @@ impl Field for RistrettoScalarField {
     type Serialization = [u8; 32];
 
     fn zero() -> Self::Scalar {
-        Scalar::zero()
+        Scalar::ZERO
     }
 
     fn one() -> Self::Scalar {
-        Scalar::one()
+        Scalar::ONE
     }
 
     fn invert(scalar: &Self::Scalar) -> Result<Self::Scalar, FieldError> {
@@ -55,7 +55,7 @@ impl Field for RistrettoScalarField {
     }
 
     fn deserialize(buf: &Self::Serialization) -> Result<Self::Scalar, FieldError> {
-        match Scalar::from_canonical_bytes(*buf) {
+        match Scalar::from_canonical_bytes(*buf).into() {
             Some(s) => Ok(s),
             None => Err(FieldError::MalformedScalar),
         }
@@ -78,7 +78,7 @@ impl Group for RistrettoGroup {
     type Serialization = [u8; 32];
 
     fn cofactor() -> <Self::Field as Field>::Scalar {
-        Scalar::one()
+        Scalar::ONE
     }
 
     fn identity() -> Self::Element {
@@ -94,7 +94,10 @@ impl Group for RistrettoGroup {
     }
 
     fn deserialize(buf: &Self::Serialization) -> Result<Self::Element, GroupError> {
-        match CompressedRistretto::from_slice(buf.as_ref()).decompress() {
+        match CompressedRistretto::from_slice(buf.as_ref())
+            .map_err(|_| GroupError::MalformedElement)?
+            .decompress()
+        {
             Some(point) => {
                 if point == Self::identity() {
                     Err(GroupError::InvalidIdentityElement)