diff --git a/zebra-chain/src/keys/sapling.rs b/zebra-chain/src/keys/sapling.rs
index 09bc37eb..19955b94 100644
--- a/zebra-chain/src/keys/sapling.rs
+++ b/zebra-chain/src/keys/sapling.rs
@@ -344,12 +344,6 @@ impl From<[u8; 32]> for OutgoingViewingKey {
     }
 }
 
-impl From<OutgoingViewingKey> for [u8; 32] {
-    fn from(nk: OutgoingViewingKey) -> [u8; 32] {
-        nk.0
-    }
-}
-
 impl From<SpendingKey> for OutgoingViewingKey {
     /// For this invocation of Blake2b-512 as _PRF^expand_, t=2.
     ///
@@ -447,12 +441,6 @@ impl From<[u8; 32]> for NullifierDerivingKey {
     }
 }
 
-impl From<NullifierDerivingKey> for [u8; 32] {
-    fn from(nk: NullifierDerivingKey) -> [u8; 32] {
-        nk.0.to_bytes()
-    }
-}
-
 impl Deref for NullifierDerivingKey {
     type Target = jubjub::AffinePoint;
 
@@ -579,12 +567,6 @@ impl From<(AuthorizingKey, NullifierDerivingKey)> for IncomingViewingKey {
     }
 }
 
-impl From<IncomingViewingKey> for [u8; 32] {
-    fn from(ivk: IncomingViewingKey) -> [u8; 32] {
-        ivk.scalar.to_bytes()
-    }
-}
-
 impl FromStr for IncomingViewingKey {
     type Err = SerializationError;