add SigningParts::{ak, alpha}

Author: conradoplg

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to Rust's notion of
 
 ## [Unreleased]
 
+- Added `SigningParts::{ak, alpha}` getters under the `unstable-frost` feature
+
 ## [0.10.1] - 2024-12-16
 
 ### Added

src/builder.rs

@@ -917,6 +917,18 @@ pub struct SigningParts {
     alpha: pallas::Scalar,
 }
 
+#[cfg(feature = "unstable-frost")]
+impl SigningParts {
+    /// Return the spend validating key for this action.
+    pub fn ak(&self) -> &SpendValidatingKey {
+        &self.ak
+    }
+    /// Return the randomization for this action.
+    pub fn alpha(&self) -> pallas::Scalar {
+        self.alpha
+    }
+}
+
 /// Marker for an unauthorized bundle with no signatures.
 #[derive(Clone, Debug)]
 pub struct Unauthorized {

src/keys.rs

@@ -334,6 +334,15 @@ impl From<FullViewingKey> for SpendValidatingKey {
 }
 
 impl FullViewingKey {
+    /// Create FVK from the given sk and ak.
+    pub fn from_sk_ak(sk: &SpendingKey, ak: SpendValidatingKey) -> Self {
+        FullViewingKey {
+            ak,
+            nk: sk.into(),
+            rivk: sk.into(),
+        }
+    }
+
     pub(crate) fn nk(&self) -> &NullifierDerivingKey {
         &self.nk
     }