JAVA高级面试进阶训练营视频教程

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windows上加解密正常，linux上加密正常，解密时发生 如下异常：

Des修改方式如下：

public void getKey(String strKey) { 

try { 

   KeyGenerator _generator = KeyGenerator.getInstance("DES"); 

   SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG"); 

   secureRandom.setSeed(strKey.getBytes()); 

   _generator.init(secureRandom); 

  this.key = _generator.generateKey(); 

  }catch (Exception e) { 

   e.printStackTrace(); 

  } 

}

AES修改方式如下： 

javax.crypto.BadPaddingException: Given final block not properly padded 

       at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
       at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
       at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
       at javax.crypto.Cipher.doFinal(DashoA13*..)
       at chb.test.crypto.AESUtils.crypt(AESUtils.java:386)
       at chb.test.crypto.AESUtils.AesDecrypt(AESUtils.java:254)
       at chb.test.crypto.AESUtils.main(AESUtils.java:40) 

解决方法： 

经过检查之后，定位在生成KEY的方法上，如下：

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1. public static SecretKey getKey (String strKey) {  
2.          try {           
3.             KeyGenerator _generator = KeyGenerator.getInstance( "AES" );  
4.             _generator.init(128, new SecureRandom(strKey.getBytes()));  
5.                 return _generator.generateKey();  
6.         }  catch (Exception e) {  
7.              throw new RuntimeException( " 初始化密钥出现异常 " );  
8.         }  
9.       }   

修改到如下方式，问题解决： 

 

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1. public static SecretKey getKey(String strKey) {  
2.        try {           
3.           KeyGenerator _generator = KeyGenerator.getInstance( "AES" );  
4.            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );  
5.           secureRandom.setSeed(strKey.getBytes());  
6.           _generator.init(128,secureRandom);  
7.               return _generator.generateKey();  
8.       }  catch (Exception e) {  
9.            throw new RuntimeException( " 初始化密钥出现异常 " );  
10.       }  
11.     }   

原因分析 

 

SecureRandom 实现完全隨操作系统本身的內部狀態，除非調用方在調用 getInstance 方法之後又調用了 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。 

 

原因二：

 

1、加密完byte[] 后，需要将加密了的byte[] 转换成base64保存，如： 
BASE64Encoder base64encoder = new BASE64Encoder(); 
String encode=base64encoder.encode(bytes)； 

2、解密前，需要将加密后的字符串从base64转回来再解密，如： 
BASE64Decoder base64decoder = new BASE64Decoder(); 
byte[] encodeByte = base64decoder.decodeBuffer(str);  

 

 

完整例子：

package com.travelsky.tdp.pkgStock.util; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; 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.spec.SecretKeySpec; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; public class SecurityAES { privatefinalstaticString encoding = "UTF-8"; /** * AES加密 * * @param content * @param password * @return */publicstaticString encryptAES(String content, String password) { byte[] encryptResult = encrypt(content, password); String encryptResultStr = parseByte2HexStr(encryptResult); // BASE64位加密 encryptResultStr = ebotongEncrypto(encryptResultStr); return encryptResultStr; } /** * AES解密 * * @param encryptResultStr * @param password * @return */publicstaticString decrypt(String encryptResultStr, String password) { // BASE64位解密String decrpt = ebotongDecrypto(encryptResultStr); byte[] decryptFrom = parseHexStr2Byte(decrpt); byte[] decryptResult = decrypt(decryptFrom, password); returnnewString(decryptResult); } /** * 加密字符串 */publicstaticString ebotongEncrypto(Stringstr) { BASE64Encoder base64encoder = new BASE64Encoder(); String result = str; if (str != null && str.length() > 0) { try { byte[] encodeByte = str.getBytes(encoding); result = base64encoder.encode(encodeByte); } catch (Exception e) { e.printStackTrace(); } } //base64加密超过一定长度会自动换行 需要去除换行符return result.replaceAll("\r\n", "").replaceAll("\r", "").replaceAll("\n", ""); } /** * 解密字符串 */publicstaticString ebotongDecrypto(Stringstr) { BASE64Decoder base64decoder = new BASE64Decoder(); try { byte[] encodeByte = base64decoder.decodeBuffer(str); returnnewString(encodeByte); } catch (IOException e) { e.printStackTrace(); returnstr; } } /** * 加密 * * @param content 需要加密的内容 * @param password 加密密码 * @return */privatestaticbyte[] encrypt(String content, String password) { try { KeyGenerator kgen = KeyGenerator.getInstance("AES"); //防止linux下 随机生成key SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" ); secureRandom.setSeed(password.getBytes()); kgen.init(128, secureRandom); //kgen.init(128, new SecureRandom(password.getBytes())); SecretKey secretKey = kgen.generateKey(); byte[] enCodeFormat = secretKey.getEncoded(); SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES"); Cipher cipher = Cipher.getInstance("AES");// 创建密码器 byte[] byteContent = content.getBytes("utf-8"); cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化 byte[] result = cipher.doFinal(byteContent); return result; // 加密 } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (NoSuchPaddingException e) { e.printStackTrace(); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } returnnull; } /**解密 * @param content 待解密内容 * @param password 解密密钥 * @return */privatestaticbyte[] decrypt(byte[] content, String password) { try { KeyGenerator kgen = KeyGenerator.getInstance("AES"); //防止linux下 随机生成key SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" ); secureRandom.setSeed(password.getBytes()); kgen.init(128, secureRandom); //kgen.init(128, new SecureRandom(password.getBytes())); SecretKey secretKey = kgen.generateKey(); byte[] enCodeFormat = secretKey.getEncoded(); SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES"); Cipher cipher = Cipher.getInstance("AES");// 创建密码器 cipher.init(Cipher.DECRYPT_MODE, key);// 初始化 byte[] result = cipher.doFinal(content); return result; // 加密 } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (NoSuchPaddingException e) { e.printStackTrace(); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } returnnull; } /**将二进制转换成16进制 * @param buf * @return */publicstaticString parseByte2HexStr(byte buf[]) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < buf.length; i++) { Stringhex = Integer.toHexString(buf & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } sb.append(hex.toUpperCase()); } return sb.toString(); } /**将16进制转换为二进制 * @param hexStr * @return */publicstaticbyte[] parseHexStr2Byte(String hexStr) { if (hexStr.length() < 1) returnnull; byte[] result = newbyte[hexStr.length()/2]; for (int i = 0;i< hexStr.length()/2; i++) { int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16); int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16); result = (byte) (high * 16 + low); } return result; } }