read iv from chiffre (still not correct but at least less wrong now)

src/main/java/ch/fhnw/kry/CTR.java

@@ -8,8 +8,8 @@ public class CTR {
     private final int iv;
     private final int key;
 
-    public CTR(int key) {
-        this.iv = generateIV();
+    public CTR(int iv, int key) {
+        this.iv = iv;
         this.key = key;
     }
 
@@ -17,7 +17,7 @@ public class CTR {
         return iv;
     }
 
-    public int generateIV() {
+    public static int generateIV() {
         Random random = ThreadLocalRandom.current();
         byte[] r = new byte[2];
         random.nextBytes(r);