Introduce VoprfParameters trait

.github/workflows/elliptic-curve.yml

@@ -49,9 +49,10 @@ jobs:
       - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features pkcs8
       - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features sec1
       - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features serde
+      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features voprf
       - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features pkcs8,sec1
       - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features pem,pkcs8,sec1
-      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features alloc,digest,ecdh,hazmat,hash2curve,jwk,pem,pkcs8,sec1,serde
+      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features alloc,digest,ecdh,hazmat,hash2curve,jwk,pem,pkcs8,sec1,serde,voprf
 
   test:
     runs-on: ubuntu-latest

elliptic-curve/Cargo.toml

@@ -56,6 +56,7 @@ jwk = ["alloc", "base64ct/alloc", "serde", "serde_json", "zeroize/alloc"]
 pem = ["alloc", "arithmetic", "pem-rfc7468/alloc", "pkcs8", "sec1/pem"]
 pkcs8 = ["sec1/pkcs8"]
 std = ["alloc", "rand_core/std"]
+voprf = ["digest"]
 
 [package.metadata.docs.rs]
 features = ["arithmetic", "ecdh", "jwk", "pem", "std"]

elliptic-curve/src/lib.rs

@@ -223,3 +223,20 @@ pub trait AlgorithmParameters: Curve {
         }
     }
 }
+
+/// Elliptic curve parameters used by VOPRF.
+#[cfg(feature = "voprf")]
+#[cfg_attr(docsrs, doc(cfg(feature = "voprf")))]
+pub trait VoprfParameters: Curve {
+    /// The `ID` parameter which identifies a particular elliptic curve
+    /// as defined in [section 4 of `draft-irtf-cfrg-voprf-08`][voprf].
+    ///
+    /// [voprf]: https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-08.html#section-4
+    const ID: u16;
+
+    /// The `Hash` parameter which assigns a particular hash function to this
+    /// ciphersuite as defined in [section 4 of `draft-irtf-cfrg-voprf-08`][voprf].
+    ///
+    /// [voprf]: https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-08.html#section-4
+    type Hash: digest::Digest;
+}