feat: add trait to convert slice into X25519PrivKey

src/lib.rs

@@ -31,6 +31,14 @@ impl From<&[u8; 32]> for X25519PubKey<'_> {
     }
 }
 
+impl From<&[u8; 8]> for X25519PrivKey<'_> {
+    fn from(value: &[u8; 8]) -> Self {
+        let mut sk = SharedPtr::<8>::new().unwrap();
+        sk.copy_from_slice(value);
+        X25519PrivKey(sk)
+    }
+}
+
 pub fn x25519_keygen<'a>() -> (X25519PrivKey<'a>, X25519PubKey<'a>) {
     let sk = X25519PrivKey(SharedPtr::<8>::new().unwrap());
     let pk = X25519PubKey(SharedPtr::<32>::new().unwrap());