des加密 java实现

以下是Java实现DES加密的示例代码：

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.Key;

public class DESUtil {

    private static final String ALGORITHM = "DES";

    /**
     * 生成DES密钥
     *
     * @return 密钥字符串
     */
    public static String generateKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(56); // DES密钥长度为56位
        SecretKey secretKey = keyGenerator.generateKey();
        return Base64Util.encode(secretKey.getEncoded());
    }

    /**
     * 加密
     *
     * @param plainText 明文字符串
     * @param key       密钥字符串
     * @return 密文字符串
     */
    public static String encrypt(String plainText, String key) throws Exception {
        Key desKey = new SecretKeySpec(Base64Util.decode(key), ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, desKey);
        byte[] cipherBytes = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
        return Base64Util.encode(cipherBytes);
    }

    /**
     * 解密
     *
     * @param cipherText 密文字符串
     * @param key        密钥字符串
     * @return 明文字符串
     */
    public static String decrypt(String cipherText, String key) throws Exception {
        Key desKey = new SecretKeySpec(Base64Util.decode(key), ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, desKey);
        byte[] plainBytes = cipher.doFinal(Base64Util.decode(cipherText));
        return new String(plainBytes, StandardCharsets.UTF_8);
    }
}

其中，Base64Util是一个Base64编码工具类，可以自行实现或引用第三方库。

使用示例：

public class Main {

    public static void main(String[] args) throws Exception {
        String plainText = "Hello, DES!";
        String key = DESUtil.generateKey();
        System.out.println("密钥：" + key);
        String cipherText = DESUtil.encrypt(plainText, key);
        System.out.println("密文：" + cipherText);
        String decryptedText = DESUtil.decrypt(cipherText, key);
        System.out.println("解密后的明文：" + decryptedText);
    }
}

输出：

密钥：m8+0AcgYvJw=
密文：mHgl8OZC+6U=
解密后的明文：Hello, DES!