Vigenere Cipher(Java)[重复]
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【中文标题】Vigenere Cipher(Java)[重复]【英文标题】:Vigenere Cipher(Java) [duplicate] 【发布时间】:2016-05-21 18:22:32 【问题描述】:我是 Java 的新手,我试图创建一个 vigenere 密码。这有点像凯撒移位,只有密钥多于一个字母,而且它是重复的,所以密码会更难破解。 我只完成了程序的加密部分,但当我意识到它运行不正常时我停止了。 我的意思是,它在某种程度上起作用,我认为,只有当我输入更长的字符串时,程序才会决定对我失败。它告诉我
线程“main”中的异常
java.lang.ArrayIndexOutOfBoundsException: 26
at Cipher.encrypt(Cipher.java:30)
at Cipher.main(Cipher.java:51)
嗯,我确实知道有一些“标准”方法可以在 Java 上制作 vigenere 密码,但我还没有了解他们正在使用的一些东西,所以我想知道你发现这个程序有什么问题。非常感谢!!!
import java.util.Scanner;
public class Cipher
public static void encrypt (char[]alpha,String p, String key)
String cipher=("");
for (int i=0; i<p.length(); i++)
char c = p.charAt(i);
int j=-1;
int k=i%key.length();
int l=-1;
do // this one finds the letter character c corresponds to in the alphabet
j=j+1;
while(c!=alpha[j]);
do// this one finds the letter that the key (or the letter used in the key) corresponds to in the alphabet
l=l+1;
while(key.charAt(k)!=alpha[l]);
if (j+l>26)//if, say, the key is z and the character is z, then they would minus the shift by 26 so it stays inside the alphabet
c=alpha[j+l-26];
else
c=alpha[j+l];
cipher=cipher+c;
System.out.println(cipher.toUpperCase());
public static void main(String[] args)
char[] alpha = "abcdefghijklmnopqrstuvwxyz".toCharArray();
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a key for your vigenere cipher");
String key= scan.nextLine().toLowerCase().replaceAll("[\\W]", "");
System.out.println("Your key is "+key.toUpperCase());
System.out.println("Would you like to encrypt or decrypt a message?");
String ans=scan.nextLine();
if (ans.equalsIgnoreCase("encrypt"))
System.out.println("Please enter your plaintext");
String p= scan.nextLine().toLowerCase().replaceAll("[\\W]", "");
System.out.println("Your plaintext is "+p);
encrypt(alpha,p,key);
else
【问题讨论】:
【参考方案1】:这是我整理的 Vigenere Cipher。
我使用的是 GUI,但您可以将 TranslateTextListener 类的密码和解密方法与控制台输入和输出一起使用。
代码如下:
package com.ggl.testing;
import java.awt.Component;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class VigenèreCipher implements Runnable
private static final Insets normalInsets = new Insets(10, 10, 0, 10);
private static final Insets finalInsets = new Insets(10, 10, 10, 10);
private JTextArea originalTextArea;
private JTextArea keyTextArea;
private JTextArea cipherTextArea;
private JTextArea uncipheredTextArea;
public static void main(String[] args)
SwingUtilities.invokeLater(new VigenèreCipher());
@Override
public void run()
JFrame frame = new JFrame("Vigenère Cipher");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createCipherPanel());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
private JPanel createCipherPanel()
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
int gridy = 0;
JLabel originalTextLabel = new JLabel("Original Text:");
addComponent(panel, originalTextLabel, 0, gridy, 1, 1, normalInsets,
GridBagConstraints.LINE_START, GridBagConstraints.HORIZONTAL);
originalTextArea = new JTextArea(5, 30);
originalTextArea.setLineWrap(true);
originalTextArea.setWrapStyleWord(true);
JScrollPane originalTextScrollPane = new JScrollPane(originalTextArea);
addComponent(panel, originalTextScrollPane, 1, gridy++, 1, 1,
normalInsets, GridBagConstraints.LINE_START,
GridBagConstraints.HORIZONTAL);
JLabel keyTextLabel = new JLabel("Key Text:");
addComponent(panel, keyTextLabel, 0, gridy, 1, 1, normalInsets,
GridBagConstraints.LINE_START, GridBagConstraints.HORIZONTAL);
keyTextArea = new JTextArea(5, 30);
keyTextArea.setLineWrap(true);
keyTextArea.setWrapStyleWord(true);
JScrollPane keyTextScrollPane = new JScrollPane(keyTextArea);
addComponent(panel, keyTextScrollPane, 1, gridy++, 1, 1, normalInsets,
GridBagConstraints.LINE_START, GridBagConstraints.HORIZONTAL);
JLabel cipherTextLabel = new JLabel("Cipher Text:");
addComponent(panel, cipherTextLabel, 0, gridy, 1, 1, finalInsets,
GridBagConstraints.LINE_START, GridBagConstraints.HORIZONTAL);
cipherTextArea = new JTextArea(5, 30);
cipherTextArea.setLineWrap(true);
JScrollPane cipherTextScrollPane = new JScrollPane(cipherTextArea);
addComponent(panel, cipherTextScrollPane, 1, gridy++, 1, 1,
finalInsets, GridBagConstraints.LINE_START,
GridBagConstraints.HORIZONTAL);
JLabel uncipheredTextLabel = new JLabel("Unciphered Text:");
addComponent(panel, uncipheredTextLabel, 0, gridy, 1, 1, finalInsets,
GridBagConstraints.LINE_START, GridBagConstraints.HORIZONTAL);
uncipheredTextArea = new JTextArea(5, 30);
uncipheredTextArea.setLineWrap(true);
uncipheredTextArea.setWrapStyleWord(true);
JScrollPane uncipheredTextScrollPane = new JScrollPane(
uncipheredTextArea);
addComponent(panel, uncipheredTextScrollPane, 1, gridy++, 1, 1,
finalInsets, GridBagConstraints.LINE_START,
GridBagConstraints.HORIZONTAL);
JButton submitButton = new JButton("Translate text");
submitButton.addActionListener(new TranslateTextListener());
addComponent(panel, submitButton, 0, gridy++, 2, 1, finalInsets,
GridBagConstraints.CENTER, GridBagConstraints.NONE);
return panel;
private void addComponent(Container container, Component component,
int gridx, int gridy, int gridwidth, int gridheight, Insets insets,
int anchor, int fill)
GridBagConstraints gbc = new GridBagConstraints(gridx, gridy,
gridwidth, gridheight, 1.0D, 1.0D, anchor, fill, insets, 0, 0);
container.add(component, gbc);
public class TranslateTextListener implements ActionListener
private char[] cipherAlphabet;
private int lowerLimit;
private int upperLimit;
public TranslateTextListener()
this.lowerLimit = 32;
this.upperLimit = 126;
this.cipherAlphabet = new char[upperLimit - lowerLimit + 1];
// Grab all the ASCII characters between space and ~, inclusive
for (int i = lowerLimit; i <= upperLimit; i++)
cipherAlphabet[i - lowerLimit] = (char) i;
@Override
public void actionPerformed(ActionEvent event)
String text = originalTextArea.getText().trim();
String key = keyTextArea.getText().trim();
String cipher = cipherTextArea.getText().trim();
String uncipher = "";
if (!text.equals("") && !key.equals(""))
cipher = cipher(text, key);
if (!key.equals("") && !cipher.equals(""))
uncipher = uncipher(cipher, key);
cipherTextArea.setText(cipher);
uncipheredTextArea.setText(uncipher);
private String cipher(String text, String key)
StringBuilder builder = new StringBuilder(text.length());
int keyIndex = 0;
for (int i = 0; i < text.length(); i++)
char c = text.charAt(i);
int pos = (int) c;
if (pos < lowerLimit || pos > upperLimit)
builder.append(c);
else
char k = key.charAt(keyIndex);
pos = getCharacterPosition(c);
int pos2 = getCharacterPosition(k);
int sum = (pos + pos2) % cipherAlphabet.length;
builder.append(getCharacter(sum));
keyIndex = ++keyIndex % key.length();
return builder.toString();
private String uncipher(String cipher, String key)
StringBuilder builder = new StringBuilder(cipher.length());
int keyIndex = 0;
for (int i = 0; i < cipher.length(); i++)
char c = cipher.charAt(i);
int pos = (int) c;
if (pos < lowerLimit || pos > upperLimit)
builder.append(c);
else
char k = key.charAt(keyIndex);
pos = getCharacterPosition(c);
int pos2 = getCharacterPosition(k);
int sum = pos - pos2;
while (sum < 0)
sum += cipherAlphabet.length;
sum = sum % cipherAlphabet.length;
builder.append(getCharacter(sum));
keyIndex = ++keyIndex % key.length();
return builder.toString();
private int getCharacterPosition(char c)
for (int i = 0; i < cipherAlphabet.length; i++)
if (c == cipherAlphabet[i])
return i;
return -1;
private char getCharacter(int index)
if (index >= 0 && index < cipherAlphabet.length)
return cipherAlphabet[index];
else
return '?';
【讨论】:
【参考方案2】:alpha
中有 26 个字符,因此有效索引为 0-25。
您检查是否j+l > 26
,并在需要时切换,但您应该检查是否j+l > 25
。
更好的是,不要使用if
进行测试并处理不同的情况,只需无条件地这样做:
c = alpha[(j + l) % 26];
另外,不要在字母表中搜索字符,而是使用减法:
j = c - 'a';
我会像这样把它们放在一起:
static String encrypt(String message, String key)
StringBuilder buf = new StringBuilder(message.length());
for (int idx = 0; idx < message.length(); ++idx)
char p = message.charAt(idx);
int j = p - 'a';
char k = key.charAt(i % key.length());
int l = k - 'a';
char c = (char) ('a' + ((j + l) % 26));
buf.append(c);
return buf.toString();
【讨论】:
【参考方案3】:尝试不同的方法?这是我的,它只是创建一个新变量来保存加密消息并根据 ASCII 值将更改的字符存储在那里。我仍然需要添加空格,到目前为止它只加密没有任何空格的消息,但它可以任意长。
public class vigenere
public static void main(String[] args)
String encryptedMessage = "";
String extended = "";
int temp, counter;
String plain_text = JOptionPane.showInputDialog("Enter the text you wish to encrypt: ");
String keyword = JOptionPane.showInputDialog("Enter the keyword: ");
counter = plain_text.length() / keyword.length() + 3;
for (int i = 0; i < counter; i++)
extended += keyword;
for (int j = 0; j < plain_text.length(); j++)
if (plain_text.charAt(j) + ((extended.charAt(j) - 97)) > 122)
temp = (int)(plain_text.charAt(j) + (extended.charAt(j) -123 ));
encryptedMessage += (char)temp;
else
temp = (int)(plain_text.charAt(j) + (extended.charAt(j) - 97 ));
encryptedMessage += (char)temp;
JOptionPane.showMessageDialog(null, encryptedMessage);
“计数器”是我们必须延长关键字多少次才能匹配明文的长度,我把+3放在最后是肯定的,但我认为+1就足够了。 另外,我对此很陌生,所以这段代码是最基本的,因为它可以得到 xD
【讨论】:
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