Linux下运行java DES解密失败，报javax.crypto.BadPaddingEx...

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java DES 加密解密

DES java源代码如下：

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
 
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
 
public class DESEncryptTest {
private static final String DES_ALGORITHM = "DES";
     
  /**
   * DES加密
   * @param plainData
   * @param secretKey
   * @return
   * @throws Exception
   */
  public String encryption(String plainData, String secretKey) throws Exception{
 
    Cipher cipher = null;
    try {
      cipher = Cipher.getInstance(DES_ALGORITHM);
      cipher.init(Cipher.ENCRYPT_MODE, generateKey(secretKey));
       
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    }catch(InvalidKeyException e){
       
    }
     
    try {
      // 为了防止解密时报javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher异常，
      // 不能把加密后的字节数组直接转换成字符串
      byte[] buf = cipher.doFinal(plainData.getBytes());
       
      return Base64Utils.encode(buf);
       
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
      throw new Exception("IllegalBlockSizeException", e);
    } catch (BadPaddingException e) {
      e.printStackTrace();
      throw new Exception("BadPaddingException", e);
    }
       
  }
 
  /**
   * DES解密
   * @param secretData
   * @param secretKey
   * @return
   * @throws Exception
   */
  public String decryption(String secretData, String secretKey) throws Exception{
     
    Cipher cipher = null;
    try {
      cipher = Cipher.getInstance(DES_ALGORITHM);
      cipher.init(Cipher.DECRYPT_MODE, generateKey(secretKey));
       
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
      throw new Exception("NoSuchAlgorithmException", e);
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
      throw new Exception("NoSuchPaddingException", e);
    }catch(InvalidKeyException e){
      e.printStackTrace();
      throw new Exception("InvalidKeyException", e);
       
    }
     
    try {
       
      byte[] buf = cipher.doFinal(Base64Utils.decode(secretData.toCharArray()));
       
      return new String(buf);
       
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
      throw new Exception("IllegalBlockSizeException", e);
    } catch (BadPaddingException e) {
      e.printStackTrace();
      throw new Exception("BadPaddingException", e);
    }
  }
   
   
  /**
   * 获得秘密密钥
   * 
   * @param secretKey
   * @return
   * @throws NoSuchAlgorithmException 
   */
  private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException{
    SecureRandom secureRandom = new SecureRandom(secretKey.getBytes());
         
    // 为我们选择的DES算法生成一个KeyGenerator对象
    KeyGenerator kg = null;
    try {
      kg = KeyGenerator.getInstance(DES_ALGORITHM);
    } catch (NoSuchAlgorithmException e) {
    }
    kg.init(secureRandom);
    //kg.init(56, secureRandom);
     
    // 生成密钥
    return kg.generateKey();
  }
       
  public static void main(String[] a) throws Exception{
    String input = "cy11Xlbrmzyh:604:301:1353064296";
    String key = "37d5aed075525d4fa0fe635231cba447";
     
    DESEncryptTest des = new DESEncryptTest();
     
    String result = des.encryption(input, key);
    System.out.println(result);
     
    System.out.println(des.decryption(result, key));
       
  }
     
  static class Base64Utils {
 
    static private char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();
    static private byte[] codes = new byte[256];
    static {
      for (int i = 0; i < 256; i++)
        codes[i] = -1;
      for (int i = 'A'; i <= 'Z'; i++)
        codes[i] = (byte) (i - 'A');
      for (int i = 'a'; i <= 'z'; i++)
        codes[i] = (byte) (26 + i - 'a');
      for (int i = '0'; i <= '9'; i++)
        codes[i] = (byte) (52 + i - '0');
      codes['+'] = 62;
      codes['/'] = 63;
    }
     
    /**
     * 将原始数据编码为base64编码
     */
    static public String encode(byte[] data) {
      char[] out = new char[((data.length + 2) / 3) * 4];
      for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {
        boolean quad = false;
        boolean trip = false;
        int val = (0xFF & (int) data[i]);
        val <<= 8;
        if ((i + 1) < data.length) {
          val |= (0xFF & (int) data[i + 1]);
          trip = true;
        }
        val <<= 8;
        if ((i + 2) < data.length) {
          val |= (0xFF & (int) data[i + 2]);
          quad = true;
        }
        out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];
        val >>= 6;
        out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];
        val >>= 6;
        out[index + 1] = alphabet[val & 0x3F];
        val >>= 6;
        out[index + 0] = alphabet[val & 0x3F];
      }
       
      return new String(out);
    }
 
    /**
     * 将base64编码的数据解码成原始数据
     */
    static public byte[] decode(char[] data) {
      int len = ((data.length + 3) / 4) * 3;
      if (data.length > 0 && data[data.length - 1] == '=')
        --len;
      if (data.length > 1 && data[data.length - 2] == '=')
        --len;
      byte[] out = new byte[len];
      int shift = 0;
      int accum = 0;
      int index = 0;
      for (int ix = 0; ix < data.length; ix++) {
        int value = codes[data[ix] & 0xFF];
        if (value >= 0) {
          accum <<= 6;
          shift += 6;
          accum |= value;
          if (shift >= 8) {
            shift -= 8;
            out[index++] = (byte) ((accum >> shift) & 0xff);
          }
        }
      }
      if (index != out.length)
        throw new Error("miscalculated data length!");
      return out;
    }
  }
}

此代码在windows下运行正常，对加密后的密文可以正常解密。运行结果如下：

xl1nEww4mm09EvMy3tETBNg8HSfTFeBoilhNT7uBKBg=
cy11Xlbrmzyh:604:301:1353064296

但是放到linux上运行，则报错，错误信息如下图：

通过图片可以看到，对相同的明文（cy11Xlbrmzyh:604:301:1353064296）进行加密，在linux上加密后的结果和在windows上是不同的；而且在linux上不能对加密之后的密文进行解密，并抛出异常。

原因：

经过检查之后，定位在生成KEY的方法上，即如下红色代码：

/**
   * 获得秘密密钥
   * 
   * @param secretKey
   * @return
   * @throws NoSuchAlgorithmException 
   */
  private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException{
    <span style="color:#ff0000;">SecureRandom secureRandom = new SecureRandom(secretKey.getBytes()); //主要是此处代码
</span>       
    // 为我们选择的DES算法生成一个KeyGenerator对象
    KeyGenerator kg = null;
    try {
      kg = KeyGenerator.getInstance(DES_ALGORITHM);
    } catch (NoSuchAlgorithmException e) {
    }
    kg.init(secureRandom);
    //kg.init(56, secureRandom);
     
    // 生成密钥
    return kg.generateKey();
  }

SecureRandom 实现完全随操作系统本身的內部状态，除非调用方在调用 getInstance 方法，然后调用 setSeed 方法；该实现在 windows 上每次生成的 key 都相同，但是在 solaris 或部分 linux 系统上则不同。关于SecureRandom类的详细介绍，见 http://yangzb.iteye.com/blog/325264

解决办法

方法1：把原来的generateKey方法中红色如下的红色部分：

/**
   * 获得秘密密钥
   * 
   * @param secretKey
   * @return
   * @throws NoSuchAlgorithmException 
   */
  private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException{
    <span style="color:#ff0000;"><span><code class="comments">//防止linux下 随机生成key</code></span>
    SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
    secureRandom.setSeed(secretKey.getBytes());
</span>   
    // 为我们选择的DES算法生成一个KeyGenerator对象
    KeyGenerator kg = null;
    try {
      kg = KeyGenerator.getInstance(DES_ALGORITHM);
    } catch (NoSuchAlgorithmException e) {
    }
    kg.init(secureRandom);
    //kg.init(56, secureRandom);
     
    // 生成密钥
    return kg.generateKey();
  }

方法2：不使用SecureRandom生成SecretKey，而是使用SecretKeyFactory；重新实现方法generateKey，代码如下

/**
   * 获得密钥
   * 
   * @param secretKey
   * @return
   * @throws NoSuchAlgorithmException 
   * @throws InvalidKeyException 
   * @throws InvalidKeySpecException 
   */
  private SecretKey generateKey(String secretKey) throws NoSuchAlgorithmException,InvalidKeyException,InvalidKeySpecException{
     
    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES_ALGORITHM);
    DESKeySpec keySpec = new DESKeySpec(secretKey.getBytes());
    keyFactory.generateSecret(keySpec);
    return keyFactory.generateSecret(keySpec);
  }

本人遇到的情况第一种方法好使，第二种不好使！

原文:http://my.oschina.net/zhk/blog/115378

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2013-03-24 23:42
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