使用换位技术执行加密的 Java 程序
使用转置技术的加密可以通过使用转置密码来完成，转置密码使用明文消息的字母，然后它们改变字母的顺序。柱状换位密码是一种换位密码，就像 围栏密码 一样。列转置包括逐行写出明文，然后逐列读出密文。
发现一个换位密码应该很容易，因为字母频率应该模仿英语的常用频率——a、e、I、n、o、r、s、t 的高频。但是，换位密码的密码分析可能很困难。最基本的技术是语法分析，即重新排列密文字母以“有意义”。密码的关键是重新排列的模式。用数学术语来说，可以简单地假设在字符位置上使用双射函数来加密，使用反函数来解密。
插图:
例 1
java Input : Plaintext : how are you Output : Ciphertext : a e oowu hyr例 2
java Input : Plaintext : you are a champion Output : Ciphertext : h aa ep o nuc i yaorm
实现: 给定一条纯文本消息和一个数字密钥，使用柱状换位密码对给定文本进行加密/解密。“你好，极客”是纯文本的自定义输入！
例
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program to Perform Cryptography
// using Transposition Technique
// Importing all classes from
// java.util package
// Importing input output classes
import java.io.*;
import java.util.*;
// Class
// For transposition cipher
public class GFG {
// Member variables of this class
public static String selectedKey;
public static char sortedKey[];
public static int sortedKeyPos[];
// Constructor 1 of this class
// Default constructor defining the default key
public GFG()
{
selectedKey = "megabuck";
sortedKeyPos = new int[selectedKey.length()];
sortedKey = selectedKey.toCharArray();
}
// Constructor 2 of this class
// Parameterized constructor defining the custom key
public GFG(String GeeksForGeeks)
{
selectedKey = GeeksForGeeks;
sortedKeyPos = new int[selectedKey.length()];
sortedKey = selectedKey.toCharArray();
}
// Method 1 - doProcessOnKey()
// To reorder data do the sorting on selected key
public static void doProcessOnKey()
{
// Find position of each character in selected key
// and arranging it in alphabetical order
int min, i, j;
char orginalKey[] = selectedKey.toCharArray();
char temp;
// Step 1: Sorting the array of selected key
// using nested for loops
for (i = 0; i < selectedKey.length(); i++) {
min = i;
for (j = i; j < selectedKey.length(); j++) {
if (sortedKey[min] > sortedKey[j]) {
min = j;
}
}
if (min != i) {
temp = sortedKey[i];
sortedKey[i] = sortedKey[min];
sortedKey[min] = temp;
}
}
// Step 2: Filling the position of array
// according to alphabetical order
// using nested for loops
for (i = 0; i < selectedKey.length(); i++) {
for (j = 0; j < selectedKey.length(); j++) {
if (orginalKey[i] == sortedKey[j])
sortedKeyPos[i] = j;
}
}
}
// Method 2 - doEncryption()
// To encrypt the targeted string
public static String doEncryption(String plainText)
{
int min, i, j;
char orginalKey[] = selectedKey.toCharArray();
char temp;
doProcessOnKey();
// Step 3: Generating the encrypted message by
// doing encryption using Transpotion Cipher
int row = plainText.length() / selectedKey.length();
int extrabit
= plainText.length() % selectedKey.length();
int exrow = (extrabit == 0) ? 0 : 1;
int rowtemp = -1, coltemp = -1;
int totallen = (row + exrow) * selectedKey.length();
char pmat[][] = new char[(row + exrow)]
[(selectedKey.length())];
char encry[] = new char[totallen];
int tempcnt = -1;
row = 0;
for (i = 0; i < totallen; i++) {
coltemp++;
if (i < plainText.length()) {
if (coltemp == (selectedKey.length())) {
row++;
coltemp = 0;
}
pmat[row][coltemp] = plainText.charAt(i);
}
else {
// Padding can be added between two
// consecutive alphabets or a group of
// alphabets of the resultant cipher text
pmat[row][coltemp] = '-';
}
}
int len = -1, k;
for (i = 0; i < selectedKey.length(); i++) {
for (k = 0; k < selectedKey.length(); k++) {
if (i == sortedKeyPos[k]) {
break;
}
}
for (j = 0; j <= row; j++) {
len++;
encry[len] = pmat[j][k];
}
}
String p1 = new String(encry);
return (new String(p1));
}
// Method 3 - doEncryption()
// To decrypt the targeted string
public static String doDecryption(String s)
{
int min, i, j, k;
char key[] = selectedKey.toCharArray();
char encry[] = s.toCharArray();
char temp;
doProcessOnKey();
// Step 4: Generating a plain message
int row = s.length();
selectedKey.length();
char pmat[][]
= new char[row][(selectedKey.length())];
int tempcnt = -1;
for (i = 0; i < selectedKey.length(); i++) {
for (k = 0; k < selectedKey.length(); k++) {
if (i == sortedKeyPos[k]) {
break;
}
}
for (j = 0; j < row; j++) {
tempcnt++;
pmat[j][k] = encry[tempcnt];
}
}
// Step 5: Storing matrix character in
// to a single string
char p1[] = new char[row * selectedKey.length()];
k = 0;
for (i = 0; i < row; i++) {
for (j = 0; j < selectedKey.length(); j++) {
if (pmat[i][j] != '*') {
p1[k++] = pmat[i][j];
}
}
}
p1[k++] = '\0';
return (new String(p1));
}
@SuppressWarnings("static-access")
// Method 4 - main()
// Main driver method
public static void main(String[] args)
{
// Creating object of class in main method
GFG tc = new GFG();
// Printing the ciphere text
// Custom input - Hello Geek
System.out.println("Cipher Text : "
+ tc.doEncryption("Hello Geek"));
}
}
Output
Cipher Text : l-o-G-ekl-e-He -
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