Data commit

Task/Chaocipher/Java/chaocipher.java

@@ -0,0 +1,81 @@
+import java.util.Arrays;
+
+public class Chaocipher {
+    private enum Mode {
+        ENCRYPT,
+        DECRYPT
+    }
+
+    private static final String L_ALPHABET = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
+    private static final String R_ALPHABET = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
+
+    private static int indexOf(char[] a, char c) {
+        for (int i = 0; i < a.length; ++i) {
+            if (a[i] == c) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private static String exec(String text, Mode mode) {
+        return exec(text, mode, false);
+    }
+
+    private static String exec(String text, Mode mode, Boolean showSteps) {
+        char[] left = L_ALPHABET.toCharArray();
+        char[] right = R_ALPHABET.toCharArray();
+        char[] eText = new char[text.length()];
+        char[] temp = new char[26];
+
+        for (int i = 0; i < text.length(); ++i) {
+            if (showSteps) {
+                System.out.printf("%s  %s\n", new String(left), new String(right));
+            }
+            int index;
+            if (mode == Mode.ENCRYPT) {
+                index = indexOf(right, text.charAt(i));
+                eText[i] = left[index];
+            } else {
+                index = indexOf(left, text.charAt(i));
+                eText[i] = right[index];
+            }
+            if (i == text.length() - 1) {
+                break;
+            }
+
+            // permute left
+
+            if (26 - index >= 0) System.arraycopy(left, index, temp, 0, 26 - index);
+            System.arraycopy(left, 0, temp, 26 - index, index);
+            char store = temp[1];
+            System.arraycopy(temp, 2, temp, 1, 12);
+            temp[13] = store;
+            left = Arrays.copyOf(temp, temp.length);
+
+            // permute right
+
+            if (26 - index >= 0) System.arraycopy(right, index, temp, 0, 26 - index);
+            System.arraycopy(right, 0, temp, 26 - index, index);
+            store = temp[0];
+            System.arraycopy(temp, 1, temp, 0, 25);
+            temp[25] = store;
+            store = temp[2];
+            System.arraycopy(temp, 3, temp, 2, 11);
+            temp[13] = store;
+            right = Arrays.copyOf(temp, temp.length);
+        }
+
+        return new String(eText);
+    }
+
+    public static void main(String[] args) {
+        String plainText = "WELLDONEISBETTERTHANWELLSAID";
+        System.out.printf("The original plaintext is : %s\n", plainText);
+        System.out.println("\nThe left and right alphabets after each permutation during encryption are:");
+        String cipherText = exec(plainText, Mode.ENCRYPT, true);
+        System.out.printf("\nThe cipher text is : %s\n", cipherText);
+        String plainText2 = exec(cipherText, Mode.DECRYPT);
+        System.out.printf("\nThe recovered plaintext is : %s\n", plainText2);
+    }
+}