Expose FerveoVariant from bindings

ferveo-python/ferveo/__init__.py

@@ -15,6 +15,7 @@
     DkgPublicKey,
     SharedSecret,
     ValidatorMessage,
+    FerveoVariant,
     ThresholdEncryptionError,
     InvalidShareNumberParameter,
     InvalidDkgStateToDeal,
@@ -32,4 +33,5 @@
     ValidatorsNotSorted,
     ValidatorPublicKeyMismatch,
     SerializationError,
+    InvalidVariant,
 )

ferveo-python/ferveo/__init__.pyi

@@ -173,6 +173,14 @@ class SharedSecret:
         ...
 
 
+class FerveoVariant:
+    @staticmethod
+    def simple() -> str: ...
+
+    @staticmethod
+    def precomputed() -> str: ...
+
+
 def encrypt(message: bytes, add: bytes, dkg_public_key: DkgPublicKey) -> Ciphertext:
     ...
 
@@ -263,3 +271,7 @@ class ValidatorPublicKeyMismatch(Exception):
 
 class SerializationError(Exception):
     pass
+
+
+class InvalidVariant(Exception):
+    pass

ferveo-python/test/test_serialization.py

@@ -4,6 +4,7 @@
     Dkg,
     DkgPublicKey,
     FerveoPublicKey,
+    FerveoVariant,
     SharedSecret,
 )
 
@@ -77,3 +78,8 @@ def test_public_key_serialization():
     deserialized = FerveoPublicKey.from_bytes(serialized)
     assert pk == deserialized
     assert len(serialized) == FerveoPublicKey.serialized_size()
+
+
+def test_ferveo_variant_serialization():
+    assert FerveoVariant.precomputed() == "FerveoVariant::Precomputed"
+    assert FerveoVariant.simple() == "FerveoVariant::Simple"

ferveo/src/api.rs

@@ -1,4 +1,4 @@
-use std::io;
+use std::{fmt, io};
 
 use ark_poly::{EvaluationDomain, Radix2EvaluationDomain};
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
@@ -69,6 +69,38 @@ pub fn decrypt_with_shared_secret(
     .map_err(Error::from)
 }
 
+/// The ferveo variant to use for the decryption share derivation.
+#[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Copy, Clone)]
+pub enum FerveoVariant {
+    /// The simple variant requires m of n shares to decrypt
+    Simple,
+    /// The precomputed variant requires n of n shares to decrypt
+    Precomputed,
+}
+
+impl fmt::Display for FerveoVariant {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.as_str())
+    }
+}
+
+impl FerveoVariant {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            FerveoVariant::Simple => "FerveoVariant::Simple",
+            FerveoVariant::Precomputed => "FerveoVariant::Precomputed",
+        }
+    }
+
+    pub fn from_string(s: &str) -> Result<Self> {
+        match s {
+            "FerveoVariant::Simple" => Ok(FerveoVariant::Simple),
+            "FerveoVariant::Precomputed" => Ok(FerveoVariant::Precomputed),
+            _ => Err(Error::InvalidVariant(s.to_string())),
+        }
+    }
+}
+
 #[serde_as]
 #[derive(Copy, Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct DkgPublicKey(

ferveo/src/bindings_python.rs

@@ -94,6 +94,9 @@ impl From<FerveoPythonError> for PyErr {
                         expected, actual
                     ))
                 }
+                Error::InvalidVariant(variant) => {
+                    InvalidVariant::new_err(variant.to_string())
+                }
             },
             _ => default(),
         }
@@ -128,6 +131,7 @@ create_exception!(exceptions, ValidatorsNotSorted, PyValueError);
 create_exception!(exceptions, ValidatorPublicKeyMismatch, PyValueError);
 create_exception!(exceptions, SerializationError, PyValueError);
 create_exception!(exceptions, InvalidByteLength, PyValueError);
+create_exception!(exceptions, InvalidVariant, PyValueError);
 
 fn from_py_bytes<T: FromBytes>(bytes: &[u8]) -> PyResult<T> {
     T::from_bytes(bytes)
@@ -267,6 +271,22 @@ pub fn decrypt_with_shared_secret(
         .map_err(|err| FerveoPythonError::FerveoError(err).into())
 }
 
+#[pyclass(module = "ferveo")]
+struct FerveoVariant {}
+
+#[pymethods]
+impl FerveoVariant {
+    #[staticmethod]
+    fn precomputed() -> &'static str {
+        api::FerveoVariant::Precomputed.as_str()
+    }
+
+    #[staticmethod]
+    fn simple() -> &'static str {
+        api::FerveoVariant::Simple.as_str()
+    }
+}
+
 #[pyclass(module = "ferveo")]
 #[derive(derive_more::AsRef)]
 pub struct SharedSecret(api::SharedSecret);
@@ -590,6 +610,7 @@ pub fn make_ferveo_py_module(py: Python<'_>, m: &PyModule) -> PyResult<()> {
     m.add_class::<DkgPublicKey>()?;
     m.add_class::<SharedSecret>()?;
     m.add_class::<ValidatorMessage>()?;
+    m.add_class::<FerveoVariant>()?;
 
     // Exceptions
     m.add(
@@ -645,6 +666,7 @@ pub fn make_ferveo_py_module(py: Python<'_>, m: &PyModule) -> PyResult<()> {
         py.get_type::<ValidatorPublicKeyMismatch>(),
     )?;
     m.add("SerializationError", py.get_type::<SerializationError>())?;
+    m.add("InvalidVariant", py.get_type::<InvalidVariant>())?;
 
     Ok(())
 }

ferveo/src/bindings_wasm.rs

@@ -161,6 +161,22 @@ macro_rules! generate_common_methods {
     };
 }
 
+#[wasm_bindgen]
+pub struct FerveoVariant {}
+
+#[wasm_bindgen]
+impl FerveoVariant {
+    #[wasm_bindgen(js_name = "precomputed", getter)]
+    pub fn precomputed() -> String {
+        api::FerveoVariant::Precomputed.as_str().to_string()
+    }
+
+    #[wasm_bindgen(js_name = "simple", getter)]
+    pub fn simple() -> String {
+        api::FerveoVariant::Simple.as_str().to_string()
+    }
+}
+
 #[derive(TryFromJsValue)]
 #[wasm_bindgen]
 #[derive(Clone, Debug, derive_more::AsRef, derive_more::From)]

ferveo/src/lib.rs

@@ -101,6 +101,9 @@ pub enum Error {
 
     #[error("Invalid byte length. Expected {0}, got {1}")]
     InvalidByteLength(usize, usize),
+
+    #[error("Invalid variant: {0}")]
+    InvalidVariant(String),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;