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。

一般情况下：

package util;

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;

public class AESUtil {

/**

* 加密

*

* @param content 需要加密的内容

* @param password  加密密码

* @return

*/

public static byte[] encrypt(String content, String password) {

try {

KeyGenerator kgen = KeyGenerator.getInstance("AES");

//kgen.init(128, new SecureRandom(password.getBytes()));

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

secureRandom.setSeed(password.getBytes());

kgen.init(128,secureRandom);

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();

}

return null;

}

/**解密

* @param content  待解密内容

* @param password 解密密钥

* @return

*/

public static byte[] decrypt(byte[] content, String password) {

try {

KeyGenerator kgen = KeyGenerator.getInstance("AES");

//kgen.init(128, new SecureRandom(password.getBytes()));

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

secureRandom.setSeed(password.getBytes());

kgen.init(128,secureRandom);

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();

}

return null;

}

/**将二进制转换成16进制

* @param buf

* @return

*/

public static String parseByte2HexStr(byte buf[]) {

StringBuffer sb = new StringBuffer();

for (int i = 0; i < buf.length; i++) {

String hex = Integer.toHexString(buf[i] & 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

*/

public static byte[] parseHexStr2Byte(String hexStr) {

if (hexStr.length() < 1)

return null;

byte[] result = new byte[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[i] = (byte) (high * 16 + low);

}

return result;

}

}