diff --git a/src/scram.erl b/src/scram.erl
index 2c4d265bc..1c1c28ec9 100644
--- a/src/scram.erl
+++ b/src/scram.erl
@@ -60,9 +60,7 @@ client_signature(StoredKey, AuthMessage) ->
 -spec client_key(binary(), binary()) -> binary().
 
 client_key(ClientProof, ClientSignature) ->
-    list_to_binary(lists:zipwith(fun (X, Y) -> X bxor Y end,
-				 binary_to_list(ClientProof),
-				 binary_to_list(ClientSignature))).
+    crypto:exor(ClientProof, ClientSignature).
 
 -spec server_signature(binary(), binary()) -> binary().
 
@@ -71,19 +69,13 @@ server_signature(ServerKey, AuthMessage) ->
 
 hi(Password, Salt, IterationCount) ->
     U1 = sha_mac(Password, <<Salt/binary, 0, 0, 0, 1>>),
-    list_to_binary(lists:zipwith(fun (X, Y) -> X bxor Y end,
-				 binary_to_list(U1),
-				 binary_to_list(hi_round(Password, U1,
-							 IterationCount - 1)))).
+    crypto:exor(U1, hi_round(Password, U1, IterationCount - 1)).
 
 hi_round(Password, UPrev, 1) ->
     sha_mac(Password, UPrev);
 hi_round(Password, UPrev, IterationCount) ->
     U = sha_mac(Password, UPrev),
-    list_to_binary(lists:zipwith(fun (X, Y) -> X bxor Y end,
-				 binary_to_list(U),
-				 binary_to_list(hi_round(Password, U,
-							 IterationCount - 1)))).
+    crypto:exor(U, hi_round(Password, U, IterationCount - 1)).
 
 sha_mac(Key, Data) ->
     crypto:hmac(sha, Key, Data).