diff --git a/Week4/VigenereBreakerOne.java b/Week4/VigenereBreakerOne.java
new file mode 100644
index 0000000..5a2bfaf
--- /dev/null
+++ b/Week4/VigenereBreakerOne.java
@@ -0,0 +1,70 @@
+package week4_assignments;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import edu.duke.*;
+
+public class VigenereBreakerOne {
+	
+	//English, Known Key Length
+	
+    public String sliceString(String message, int whichSlice, int totalSlices) {
+        int len = message.length();
+        
+        int limit = (len - whichSlice) / totalSlices + Math.min((len - whichSlice) % totalSlices, 1);
+        
+        String s = Stream.iterate(whichSlice, i -> i + totalSlices)
+        .limit(limit)
+        .map(message::charAt)
+        .map(String::valueOf)
+        .collect(Collectors.joining());
+        return s;
+    }
+
+    public int[] tryKeyLength(String encrypted, int klength, char mostCommon) {
+    	CaesarCracker ccr = new CaesarCracker(mostCommon);
+    	List<Integer> keyList = IntStream.range(0, klength).boxed().parallel()
+    	.map(i -> {
+    		return ccr.getKey(sliceString(encrypted,(int)i,klength));
+    	})
+    	.collect(Collectors.toList());
+    	return keyList.stream().mapToInt(x -> x).toArray();    	
+    	
+    }
+
+    public void breakVigenere () {
+    	FileResource fr = new FileResource("data/secretmessage1.txt");
+    	String encrypted = fr.asString();
+    	int[] key = tryKeyLength(encrypted, 4, 'e');
+    	System.out.println(key);
+    	VigenereCipher cipher = new VigenereCipher(key);
+    	String decrypted = cipher.decrypt(encrypted);
+    	System.out.println("Decrypted Message: " + decrypted);
+    }
+    
+    public static void main(String[] args) {
+    	VigenereBreakerOne breaker = new VigenereBreakerOne();
+    	
+    	assert breaker.sliceString("abcdefghijklm", 0, 3).equals("adgjm") : "not right";
+    	assert breaker.sliceString("abcdefghijklm", 1, 3).equals("behk") : "not right";
+    	assert breaker.sliceString("abcdefghijklm", 2, 3).equals("cfil") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 0, 4).equals("aeim") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 1, 4).equals("bfj") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 2, 4).equals("cgk") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 3, 4).equals("dhl") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 0, 5).equals("afk") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 1, 5).equals("bgl") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 2, 5).equals("chm") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 3, 5).equals("di") : "not right";
+		assert breaker.sliceString("abcdefghijklm", 4, 5).equals("ej") : "not right";
+		
+		breaker.breakVigenere();
+    }
+    
+    
+    
+}