Crypto/src/Caesar.java

+public class Caesar extends ROT13{
+    public Caesar() {
+        super();
+    }
+}

Crypto/src/ROT13.java

 
 public class ROT13  {
 
+    private final String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    private final string lowercaseStart = "abcdefghijklmnopqrstuvwxyz";
+
     ROT13(Character cs, Character cf) {
     }
 
 
 
     public String crypt(String text) throws UnsupportedOperationException {
-
-        return "";
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < input.length(); i++) {
+            char c = text.charAt(i);
+            if       (c >= 'a' && c <= 'm') c += 13;
+            else if  (c >= 'A' && c <= 'M') c += 13;
+            else if  (c >= 'n' && c <= 'z') c -= 13;
+            else if  (c >= 'N' && c <= 'Z') c -= 13;
+            sb.append(c);
+        }
+        return sb.toString();
+    }
     }
 
     public String encrypt(String text) {
-        return text;
+      crypt(text);
     }
 
     public String decrypt(String text) {
-        return text;
+        crypt(text);
     }
 
     public static String rotate(String s, Character c) {
+        if ( Character.isLowerCase( (s) c ) )
+        {
+            return ( ( c - (int)'a' + 13 ) % 26 + (int)'a' );
+        }
+        else
+        if ( Character.isUpperCase( (s) c ) )
+        {
+            return ( ( c - (int)'A' + 13 ) % 26 + (int)'A' );
+        }
+        else
+        {
+            return (int)' ';
+        }
 
-        return "";
     }
 
 }

SimpleCrypt.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_5">
+    <output url="file://$MODULE_DIR$/target/classes" />
+    <output-test url="file://$MODULE_DIR$/target/test-classes" />
+    <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>