e53ec53034
- Remove continue; - Change condition with Character.isLetter() and Character.isUpperCase();
68 lines
1.8 KiB
Java
68 lines
1.8 KiB
Java
package ciphers;
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/**
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* A Java implementation of Vigenere Cipher.
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* @author straiffix
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*/
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public class Vigenere {
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public static String encrypt(final String message, final String key)
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{
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String result = "";
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for (int i = 0, j = 0; i < message.length(); i++) {
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char c = message.charAt(i);
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if (Character.isLetter(c)){
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if(Character.isUpperCase(c)) {
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result += (char) ((c + key.toUpperCase().charAt(j) - 2 * 'A') % 26 + 'A');
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} else {
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result += (char) ((c + key.toLowerCase().charAt(j) - 2 * 'a') % 26 + 'a');
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}
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} else {
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result+=c;
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}
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j = ++j % key.length();
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}
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return result;
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}
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public static String decrypt( final String message, final String key)
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{
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String result ="";
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for(int i = 0, j = 0; i < message.length(); i++){
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char c = message.charAt(i);
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if (Character.isLetter(c)){
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if(Character.isUpperCase(c)) {
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result += ((char)('Z'-(25-(c-key.toUpperCase().charAt(j)))%26));
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} else {
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result += ((char)('z'-(25-(c-key.toLowerCase().charAt(j)))%26));
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}
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} else {
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result+=c;
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}
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j = ++j % key.length();
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}
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return result;
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}
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public static void main (String [] args){
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String text="Hello World!";
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String key="itsakey";
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System.out.println(text);
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String ciphertext=encrypt(text, key);
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System.out.println(ciphertext);
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System.out.println(decrypt(ciphertext, key));
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}
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}
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