diff --git a/src/ascon.rs b/src/ascon.rs
index 6cad6ac..6361374 100644
--- a/src/ascon.rs
+++ b/src/ascon.rs
@@ -69,17 +69,11 @@ fn sbox(input: [u64; 5]) -> [u64; 5] {
     x4 ^= x3;
     x2 ^= x1;
 
-    let mut t0 = !x0;
-    let mut t1 = !x1;
-    let mut t2 = !x2;
-    let mut t3 = !x3;
-    let mut t4 = !x4;
-
-    t0 &= x1;
-    t1 &= x2;
-    t2 &= x3;
-    t3 &= x4;
-    t4 &= x0;
+    let t0 = !x0 & x1;
+    let t1 = !x1 & x2;
+    let t2 = !x2 & x3;
+    let t3 = !x3 & x4;
+    let t4 = !x4 & x0;
 
     x0 ^= t1;
     x1 ^= t2;