Added Vigenere cipher
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135
src/main/java/mattrixwv/CipherStreamJava/Vigenere.java
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135
src/main/java/mattrixwv/CipherStreamJava/Vigenere.java
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//CipherStreamJava/src/main/java/mattrixwv/CipherStreamJava/Vigenere.java
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//Matthew Ellison
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// Created: 07-25-21
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//Modified: 07-25-21
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//This is the declaration of the Vigenere class
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package mattrixwv.CipherStreamJava;
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import java.util.ArrayList;
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public class Vigenere{
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public static final String version = "1.0"; //The current library's version number
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private String inputString; //This is the string that needs encoded/decoded
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private String outputString; //This is the string that is output after encoding/decoding
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private String keyword; //This is the keyword that is resposible for determining the offsets that you change each character by
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private ArrayList<Integer> offset; //Holds the offsets coputed from each character in the keyword
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//Uses keyword to calculate the offset for the Caesar cipher for each character
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private void setOffset(){
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//Reserve the correct size to increase speed later
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offset.ensureCapacity(keyword.length());
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//Loop through every letter in keyword and get the offset from A
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for(int cnt = 0;cnt < keyword.length();++cnt){
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char letter = keyword.charAt(cnt);
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offset.add((letter - 'A') % 26);
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}
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}
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//Sets inputString
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private void setInputString(String input){
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//Convert all letters to uppercase
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input = input.toUpperCase();
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//Remove all characters except capital letters
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input = input.replaceAll("[^A-Z]", "");
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//Save the string
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inputString = input;
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}
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//Sets keyword
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private void setKeyword(String key) throws Exception{
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//Convert all letters to uppercase
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key = key.toUpperCase();
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//Remove all characters except capital letters
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key = key.replaceAll("[^A-Z]", "");
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//Save the string
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keyword = key;
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//Make sure offset is empty before adding to it
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offset.clear();
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setOffset();
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//If after all the eliminating of unusable characters the keyword is empty throw an exception
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if(keyword == ""){
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throw new Exception("The keyword cannot be empty");
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}
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}
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//Encodes inputString and stores the result in outputString
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private String encode(){
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StringBuilder output = new StringBuilder();
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//Step through every character in the inputString and advance it the correct amount, according to offset
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for(int cnt = 0;cnt < inputString.length();++cnt){
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char letter = (char)(inputString.charAt(cnt) + offset.get(cnt % offset.size()));
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//Make sure the character is still a letter, if not, wrap around
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if(letter < 'A'){
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letter += 26;
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}
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else if(letter > 'Z'){
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letter -= 26;
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}
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output.append(letter);
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}
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outputString = output.toString();
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return outputString;
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}
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//Decodes inputString and stores the result in outputString
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private String decode(){
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StringBuilder output = new StringBuilder();
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//Step through every character in the inputString and advance it the correct amount, according to offset
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for(int cnt = 0;cnt < inputString.length();++cnt){
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char letter = (char)(inputString.charAt(cnt) - offset.get(cnt % offset.size()));
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if(letter < 'A'){
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letter += 26;
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}
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else if(letter > 'Z'){
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letter -= 26;
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}
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output.append(letter);
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}
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outputString = output.toString();
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return outputString;
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}
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//Constructor
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public Vigenere(){
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offset = new ArrayList<Integer>();
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reset();
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}
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//Returns the current inputString
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public String getInputString(){
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return inputString;
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}
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//Returns the current outputString
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public String getOutputString(){
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return outputString;
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}
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//Returns the current keyword
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public String getKeyword(){
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return keyword;
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}
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//Returns the current offsets (Used mostly in bug fixing)
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public ArrayList<Integer> getOffsets(){
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return offset;
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}
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//Encodes input using key and returns the result
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public String encode(String key, String input) throws Exception{
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reset();
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setKeyword(key);
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setInputString(input);
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return encode();
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}
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//Decodes input using key and returns the result
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public String decode(String key, String input) throws Exception{
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reset();
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setKeyword(key);
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setInputString(input);
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return decode();
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}
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//Makes sure all of the variables are empty
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public void reset(){
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inputString = outputString = keyword = "";
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offset.clear();
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}
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}
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65
src/test/java/mattrixwv/CipherStreamJava/TestVigenere.java
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65
src/test/java/mattrixwv/CipherStreamJava/TestVigenere.java
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@@ -0,0 +1,65 @@
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//CipherStreamJava/src/main/java/mattrixwv/CipherStreamJava/TestVigenere.java
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//Matthew Ellison
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// Created: 07-25-21
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//Modified: 07-25-21
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//These are the tests for the Vigenere class
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package mattrixwv.CipherStreamJava;
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import static org.junit.Assert.assertEquals;
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import org.junit.Test;
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public class TestVigenere{
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@Test
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public void testDecode() throws Exception{
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Vigenere cipher = new Vigenere();
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//Test 1
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String input = "xzb";
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String keyword = "xyz";
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String correctOutput = "ABC";
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String output = cipher.decode(keyword, input);
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assertEquals("Vigenere Decoding failed the first test", correctOutput, output);
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//Test 2
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input = "LXFOPVEFRNHR";
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keyword = "LEMON";
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correctOutput = "ATTACKATDAWN";
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output = cipher.decode(keyword, input);
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assertEquals("Vigenere Decoding failed the second test", correctOutput, output);
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//Test 3
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input = "CSASTPKVSIQUTGQUCSASTPIUAQJB";
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keyword = "ABCD";
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correctOutput = "CRYPTOISSHORTFORCRYPTOGRAPHY";
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output = cipher.decode(keyword, input);
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assertEquals("Vigenere Decoding failed the third test", correctOutput, output);
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}
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@Test
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public void testEncode() throws Exception{
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Vigenere cipher = new Vigenere();
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//Test 1
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String input = "abc";
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String keyword = "xyz";
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String correctOutput = "XZB";
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String output = cipher.encode(keyword, input);
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assertEquals("Vigenere Encoding failed the first test", correctOutput, output);
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//Test 2
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input = "Attack at dawn";
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keyword = "Lemon";
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correctOutput = "LXFOPVEFRNHR";
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output = cipher.encode(keyword, input);
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assertEquals("Vigenere Encoding failed the second test", correctOutput, output);
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//Test 3
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input = "'Crypto' is short for 'Cryptography'";
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keyword = "abcd";
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correctOutput = "CSASTPKVSIQUTGQUCSASTPIUAQJB";
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output = cipher.encode(keyword, input);
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assertEquals("Vigenere Encoding failed the third test", correctOutput, output);
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}
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}
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