diff --git a/src/main/java/ch/fhnw/kry/SPN.java b/src/main/java/ch/fhnw/kry/SPN.java
index 3b9ef91..a0f83b3 100644
--- a/src/main/java/ch/fhnw/kry/SPN.java
+++ b/src/main/java/ch/fhnw/kry/SPN.java
@@ -88,7 +88,7 @@ public class SPN {
         for (int i = 3; i > 0; i--) {
             x = substitution(x, SBOX_REVERSE);
             x = permutation(x);
-            x ^= k(key, i);
+            x ^= permutation(k(key, i));
         }
 
         x = substitution(x, SBOX_REVERSE);
diff --git a/src/test/java/ch/fhnw/kry/SPNTest.java b/src/test/java/ch/fhnw/kry/SPNTest.java
index 782408b..4c18b3f 100644
--- a/src/test/java/ch/fhnw/kry/SPNTest.java
+++ b/src/test/java/ch/fhnw/kry/SPNTest.java
@@ -63,7 +63,7 @@ class SPNTest {
     }
 
     @Test
-    void sp() {
+    void blockEncryptionDecryption() {
         var spn = new SPN();
 
         int x = 0x128F ;