Have Decapsulator::encapsulator borrow

Adds a `Clone` bound to obtain an owned result

Author: tarcieri

kem/src/lib.rs

@@ -68,10 +68,11 @@ pub trait Encapsulate: Kem + TryKeyInit + KeyExport {
 pub trait Decapsulator: Kem {
     /// Encapsulator which corresponds to this decapsulator.
     type Encapsulator: Encapsulate
+        + Clone
         + Kem<CiphertextSize = Self::CiphertextSize, SharedSecretSize = Self::SharedSecretSize>;
 
     /// Retrieve the encapsulator associated with this decapsulator.
-    fn encapsulator(&self) -> Self::Encapsulator;
+    fn encapsulator(&self) -> &Self::Encapsulator;
 }
 
 /// Decapsulator for encapsulated keys, with an associated `Encapsulator` bounded by the