idk how to read actually

backend/src/main/java/com/crypto/Caesar.java

@@ -14,13 +14,22 @@ public class Caesar {
     public static String[] decode(String ciphertext){
         String alphabet = "abcdefghijklmnopqrstuvwxyz";
         char encoded[] = ciphertext.toCharArray();
+
         char decoded[] = new char[ciphertext.length()];
         String bruteforce[] = new String[26];
+
         for(int key = 0; key < alphabet.length(); key++){
+
             for(int i = 0; i < ciphertext.length(); i++){
-                decoded[i] = alphabet.charAt(alphabet.indexOf((encoded[i] + key) % 26));
+                char current = encoded[i];
+                int pos = alphabet.indexOf(current);
+                if(pos != -1) {
+                    int newpos = (pos + key) % 26;
+                    decoded[i] = alphabet.charAt(newpos);
+                } else
+                    decoded[i] = current;
             }
-            bruteforce[key] = String.valueOf(encoded);
+            bruteforce[key] = String.valueOf(decoded);
         }
         return bruteforce;