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