TheAlgorithms · yanglbme · Jun 5, 2021 · Jun 5, 2021
@@ -4,50 +4,51 @@
 * A Java implementation of Vigenere Cipher.
 *
 * @author straiffix
+ * @author beingmartinbmc
 */
 public class Vigenere {

  public static String encrypt(final String message, final String key) {

-    String result = "";
+    StringBuilder result = new StringBuilder();

    for (int i = 0, j = 0; i < message.length(); i++) {
      char c = message.charAt(i);
      if (Character.isLetter(c)) {
        if (Character.isUpperCase(c)) {
-          result += (char) ((c + key.toUpperCase().charAt(j) - 2 * 'A') % 26 + 'A');
+          result.append((char) ((c + key.toUpperCase().charAt(j) - 2 * 'A') % 26 + 'A'));

        } else {
-          result += (char) ((c + key.toLowerCase().charAt(j) - 2 * 'a') % 26 + 'a');
+          result.append((char) ((c + key.toLowerCase().charAt(j) - 2 * 'a') % 26 + 'a'));
        }
      } else {
-        result += c;
+        result.append(c);
      }
      j = ++j % key.length();
    }
-    return result;
+    return result.toString();
  }

  public static String decrypt(final String message, final String key) {
-    String result = "";
+    StringBuilder result = new StringBuilder();

    for (int i = 0, j = 0; i < message.length(); i++) {

      char c = message.charAt(i);
      if (Character.isLetter(c)) {
        if (Character.isUpperCase(c)) {
-          result += ((char) ('Z' - (25 - (c - key.toUpperCase().charAt(j))) % 26));
+          result.append((char) ('Z' - (25 - (c - key.toUpperCase().charAt(j))) % 26));

        } else {
-          result += ((char) ('z' - (25 - (c - key.toLowerCase().charAt(j))) % 26));
+          result.append((char) ('z' - (25 - (c - key.toLowerCase().charAt(j))) % 26));
        }
      } else {
-        result += c;
+        result.append(c);
      }

      j = ++j % key.length();
    }
-    return result;
+    return result.toString();
  }

  public static void main(String[] args) {