PHP实现vigenere cipher维吉尼亚密码算法(附完整源码)

以下是Java实现维吉尼亚密码加解密算法的完整源码： ```java import java.util.Scanner; public class VigenereCipher { private static final String ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; public static void main(String[] args) { Scanner scanner = new Scanner(System.in); // 读取明文和密钥 System.out.print("请输入明文："); String plainText = scanner.nextLine().toUpperCase(); System.out.print("请输入密钥："); String key = scanner.nextLine().toUpperCase(); // 加密 String cipherText = encrypt(plainText, key); System.out.println("加密后的密文为：" + cipherText); // 解密 String decryptedText = decrypt(cipherText, key); System.out.println("解密后的明文为：" + decryptedText); scanner.close(); } /** * 维吉尼亚密码加密 * * @param plainText 明文 * @param key 密钥 * @return 密文 */ public static String encrypt(String plainText, String key) { StringBuilder cipherText = new StringBuilder(); int keyIndex = 0; for (char c : plainText.toCharArray()) { if (Character.isLetter(c)) { int plainTextIndex = ALPHABET.indexOf(c); int keyCharIndex = ALPHABET.indexOf(key.charAt(keyIndex)); int cipherTextIndex = (plainTextIndex + keyCharIndex) % ALPHABET.length(); cipherText.append(ALPHABET.charAt(cipherTextIndex)); keyIndex = ++keyIndex % key.length(); } else { cipherText.append(c); } } return cipherText.toString(); } /** * 维吉尼亚密码解密 * * @param cipherText 密文 * @param key 密钥 * @return 明文 */ public static String decrypt(String cipherText, String key) { StringBuilder plainText = new StringBuilder(); int keyIndex = 0; for (char c : cipherText.toCharArray()) { if (Character.isLetter(c)) { int cipherTextIndex = ALPHABET.indexOf(c); int keyCharIndex = ALPHABET.indexOf(key.charAt(keyIndex)); int plainTextIndex = (cipherTextIndex - keyCharIndex + ALPHABET.length()) % ALPHABET.length(); plainText.append(ALPHABET.charAt(plainTextIndex)); keyIndex = ++keyIndex % key.length(); } else { plainText.append(c); } } return plainText.toString(); } } ``` 使用时，只需在主函数中调用 `encrypt` 和 `decrypt` 方法即可。注意，这里使用的是大写字母表，如果要支持小写字母，可以在字母表中添加小写字母即可。