Java实现DES加解密算法解析

package com.favccxx.codelib;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
public class EncryptCoder {
           
  private final static String DES = "DES";
           
  public static byte[] encrypt(byte[] src, byte[] key) throws Exception {
    // DES算法要求有一个可信任的随机数源
    SecureRandom sr = new SecureRandom();
    // 从原始密匙数据创建DESKeySpec对象
    DESKeySpec dks = new DESKeySpec(key);
    // 创建一个密匙工厂，然后用它把DESKeySpec转换成一个SecretKey对象
    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
    SecretKey securekey = keyFactory.generateSecret(dks);
    // Cipher对象实际完成加密操作
    Cipher cipher = Cipher.getInstance(DES);
    // 用密匙初始化Cipher对象
    cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
    // 正式执行加密操作
    return cipher.doFinal(src);
  }
           
  /**
   *
   * @param password 密码
   * @param key 加密字符串
   * @return
   */
  public final static String encrypt(String password, String key) {
    try {
      return byte2String(encrypt(password.getBytes(), key.getBytes()));
    } catch (Exception e) {
    }
    return null;
  }
           
  public static String byte2String(byte[] b) {
    String hs = "";
    String stmp = "";
    for (int n = 0; n < b.length; n++) {
      stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
      if (stmp.length() == 1)
        hs = hs + "0" + stmp;
      else
        hs = hs + stmp;
    }
    return hs.toUpperCase();
  }           
  public static void main(String[] args){
    String encryptString = encrypt("is张三丰","test中英文杂七烂八混搭@123654{");
    System.out.println(encryptString);
  }          
  //输出：B00542E93695F4CFCE34FC4393C2F4BF          
}

package com.favccxx.codelib;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
public class DescryptCoder {
     
  private final static String DES = "DES";
     
  /**
   *
   * @param src 数据源
   * @param key 密钥，长度必须是8的倍数
   * @return
   * @throws Exception
   */
  public static byte[] decrypt(byte[] src, byte[] key) throws Exception {
    // DES算法要求有一个可信任的随机数源
    SecureRandom sr = new SecureRandom();
    // 从原始密匙数据创建一个DESKeySpec对象
    DESKeySpec dks = new DESKeySpec(key);
    // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成一个SecretKey对象
    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
    SecretKey securekey = keyFactory.generateSecret(dks);
    // Cipher对象实际完成解密操作
    Cipher cipher = Cipher.getInstance(DES);
    // 用密匙初始化Cipher对象
    cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
       
    // 正式执行解密操作
    return cipher.doFinal(src);
  }
     
  public final static String decrypt(String data, String key) {
    try {
      return new String(decrypt(String2byte(data.getBytes()), key.getBytes()));
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
     
  public static byte[] String2byte(byte[] b) {
    if ((b.length % 2) != 0)
      throw new IllegalArgumentException("长度不是偶数");
    byte[] b2 = new byte[b.length / 2];
    for (int n = 0; n < b.length; n += 2) {
      String item = new String(b, n, 2);
      b2[n / 2] = (byte) Integer.parseInt(item, 16);
    }
    return b2;
  }
     
  public static void main(String[] args){
    String desencryptString = decrypt("B00542E93695F4CFCE34FC4393C2F4BF","test中英文杂七烂八混搭@123654");
    System.out.println(desencryptString);
  }
     
  //输出：is张三丰
}