diff --git a/src/main/java/de/srsoftware/widerhall/Util.java b/src/main/java/de/srsoftware/widerhall/Util.java
index a962d32..9af1685 100644
--- a/src/main/java/de/srsoftware/widerhall/Util.java
+++ b/src/main/java/de/srsoftware/widerhall/Util.java
@@ -1,16 +1,12 @@
 package de.srsoftware.widerhall;
 
-import de.srsoftware.examples.translations.App;
 import de.srsoftware.tools.translations.Translation;
 
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.util.Arrays;
-import java.util.List;
 import java.util.Map;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
 public class Util {
@@ -51,8 +47,10 @@ public class Util {
         return buf.toString();
     }
 
-    private static String hex(byte b){
-        return (b<16 ? "0" : "") + Integer.toHexString(b);
+    public static String hex(int b){
+        int lower = b & 0x0F;
+        int upper = (b & 0xF0) >> 4;
+        return (char)(upper < 10 ? '0'+upper : 'A'+upper-10)+""+(char)(lower < 10 ? '0'+lower : 'A'+lower-10);
     }
 
     public static String t(String tx, Object ... fills){
diff --git a/src/test/java/de/srsoftware/widerhall/UtilTest.java b/src/test/java/de/srsoftware/widerhall/UtilTest.java
new file mode 100644
index 0000000..17ece1c
--- /dev/null
+++ b/src/test/java/de/srsoftware/widerhall/UtilTest.java
@@ -0,0 +1,44 @@
+package de.srsoftware.widerhall;
+
+import junit.framework.TestCase;
+
+import java.util.Map;
+import java.util.TreeMap;
+
+public class UtilTest extends TestCase {
+
+    public void testUrlEncode() {
+        TreeMap<String,Object> map = new TreeMap<>();
+        map.put("a",1);
+        map.put("b",2);
+        map.put("c","&");
+        map.put("d","=");
+        assertEquals("a=1&b=2&c=%26&d=%3D",Util.urlEncode(map));
+    }
+
+    public void testHex(){
+        assertEquals("00",Util.hex(0));
+        assertEquals("09",Util.hex(9));
+        assertEquals("0A",Util.hex(10));
+        assertEquals("0F",Util.hex(15));
+        assertEquals("10",Util.hex(16));
+        assertEquals("19",Util.hex(25));
+        assertEquals("FF",Util.hex(255));
+    }
+
+    public void testSha256() {
+        assertEquals("9F722959A023C02A3BA0FAFDBA81ADED642D6610EFF5DCA32DCE35132E16B6C5",Util.sha256("Dies ist ein Test"));
+    }
+
+    public void testTranslate() {
+        assertEquals("Dies ist ein Test",Util.t("{} {} {} {}","Dies","ist","ein","Test"));
+    }
+
+    public void testIsEmail() {
+        // TODO
+    }
+
+    public void testSimplePassword() {
+        // TODO
+    }
+}
\ No newline at end of file