Added Vigenere cipher

src/main/java/mattrixwv/CipherStreamJava/Vigenere.java

@@ -0,0 +1,135 @@
+//CipherStreamJava/src/main/java/mattrixwv/CipherStreamJava/Vigenere.java
+//Matthew Ellison
+// Created: 07-25-21
+//Modified: 07-25-21
+//This is the declaration of the Vigenere class
+package mattrixwv.CipherStreamJava;
+
+import java.util.ArrayList;
+
+public class Vigenere{
+	public static final String version = "1.0";	//The current library's version number
+	private String inputString;	//This is the string that needs encoded/decoded
+	private String outputString;	//This is the string that is output after encoding/decoding
+	private String keyword;		//This is the keyword that is resposible for determining the offsets that you change each character by
+	private ArrayList<Integer> offset;	//Holds the offsets coputed from each character in the keyword
+
+	//Uses keyword to calculate the offset for the Caesar cipher for each character
+	private void setOffset(){
+		//Reserve the correct size to increase speed later
+		offset.ensureCapacity(keyword.length());
+
+		//Loop through every letter in keyword and get the offset from A
+		for(int cnt = 0;cnt < keyword.length();++cnt){
+			char letter = keyword.charAt(cnt);
+			offset.add((letter - 'A') % 26);
+		}
+	}
+	//Sets inputString
+	private void setInputString(String input){
+		//Convert all letters to uppercase
+		input = input.toUpperCase();
+		//Remove all characters except capital letters
+		input = input.replaceAll("[^A-Z]", "");
+		//Save the string
+		inputString = input;
+	}
+	//Sets keyword
+	private void setKeyword(String key) throws Exception{
+		//Convert all letters to uppercase
+		key = key.toUpperCase();
+		//Remove all characters except capital letters
+		key = key.replaceAll("[^A-Z]", "");
+		//Save the string
+		keyword = key;
+
+		//Make sure offset is empty before adding to it
+		offset.clear();
+		setOffset();
+		//If after all the eliminating of unusable characters the keyword is empty throw an exception
+		if(keyword == ""){
+			throw new Exception("The keyword cannot be empty");
+		}
+	}
+	//Encodes inputString and stores the result in outputString
+	private String encode(){
+		StringBuilder output = new StringBuilder();
+
+		//Step through every character in the inputString and advance it the correct amount, according to offset
+		for(int cnt = 0;cnt < inputString.length();++cnt){
+			char letter = (char)(inputString.charAt(cnt) + offset.get(cnt % offset.size()));
+			//Make sure the character is still a letter, if not, wrap around
+			if(letter < 'A'){
+				letter += 26;
+			}
+			else if(letter > 'Z'){
+				letter -= 26;
+			}
+			output.append(letter);
+		}
+
+		outputString = output.toString();
+		return outputString;
+	}
+	//Decodes inputString and stores the result in outputString
+	private String decode(){
+		StringBuilder output = new StringBuilder();
+
+		//Step through every character in the inputString and advance it the correct amount, according to offset
+		for(int cnt = 0;cnt < inputString.length();++cnt){
+			char letter = (char)(inputString.charAt(cnt) - offset.get(cnt % offset.size()));
+			if(letter < 'A'){
+				letter += 26;
+			}
+			else if(letter > 'Z'){
+				letter -= 26;
+			}
+			output.append(letter);
+		}
+
+		outputString = output.toString();
+		return outputString;
+	}
+
+
+	//Constructor
+	public Vigenere(){
+		offset = new ArrayList<Integer>();
+		reset();
+	}
+	//Returns the current inputString
+	public String getInputString(){
+		return inputString;
+	}
+	//Returns the current outputString
+	public String getOutputString(){
+		return outputString;
+	}
+	//Returns the current keyword
+	public String getKeyword(){
+		return keyword;
+	}
+	//Returns the current offsets (Used mostly in bug fixing)
+	public ArrayList<Integer> getOffsets(){
+		return offset;
+	}
+	//Encodes input using key and returns the result
+	public String encode(String key, String input) throws Exception{
+		reset();
+		setKeyword(key);
+		setInputString(input);
+		return encode();
+	}
+	//Decodes input using key and returns the result
+	public String decode(String key, String input) throws Exception{
+		reset();
+		setKeyword(key);
+		setInputString(input);
+		return decode();
+	}
+	//Makes sure all of the variables are empty
+	public void reset(){
+		inputString = outputString = keyword = "";
+		offset.clear();
+	}
+}

src/test/java/mattrixwv/CipherStreamJava/TestVigenere.java

@@ -0,0 +1,65 @@
+//CipherStreamJava/src/main/java/mattrixwv/CipherStreamJava/TestVigenere.java
+//Matthew Ellison
+// Created: 07-25-21
+//Modified: 07-25-21
+//These are the tests for the Vigenere class
+package mattrixwv.CipherStreamJava;
+
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+
+public class TestVigenere{
+	@Test
+	public void testDecode() throws Exception{
+		Vigenere cipher = new Vigenere();
+
+		//Test 1
+		String input = "xzb";
+		String keyword = "xyz";
+		String correctOutput = "ABC";
+		String output = cipher.decode(keyword, input);
+		assertEquals("Vigenere Decoding failed the first test", correctOutput, output);
+
+		//Test 2
+		input = "LXFOPVEFRNHR";
+		keyword = "LEMON";
+		correctOutput = "ATTACKATDAWN";
+		output = cipher.decode(keyword, input);
+		assertEquals("Vigenere Decoding failed the second test", correctOutput, output);
+
+		//Test 3
+		input = "CSASTPKVSIQUTGQUCSASTPIUAQJB";
+		keyword = "ABCD";
+		correctOutput = "CRYPTOISSHORTFORCRYPTOGRAPHY";
+		output = cipher.decode(keyword, input);
+		assertEquals("Vigenere Decoding failed the third test", correctOutput, output);
+	}
+	@Test
+	public void testEncode() throws Exception{
+		Vigenere cipher = new Vigenere();
+
+		//Test 1
+		String input = "abc";
+		String keyword = "xyz";
+		String correctOutput = "XZB";
+		String output = cipher.encode(keyword, input);
+		assertEquals("Vigenere Encoding failed the first test", correctOutput, output);
+
+		//Test 2
+		input = "Attack at dawn";
+		keyword = "Lemon";
+		correctOutput = "LXFOPVEFRNHR";
+		output = cipher.encode(keyword, input);
+		assertEquals("Vigenere Encoding failed the second test", correctOutput, output);
+
+		//Test 3
+		input = "'Crypto' is short for 'Cryptography'";
+		keyword = "abcd";
+		correctOutput = "CSASTPKVSIQUTGQUCSASTPIUAQJB";
+		output = cipher.encode(keyword, input);
+		assertEquals("Vigenere Encoding failed the third test", correctOutput, output);
+	}
+}