badPaddingException对doFinal的一些调用。不是全部。相同的输入 [英] badPaddingException on some call of the doFinal. Not all. Same input
本文介绍了badPaddingException对doFinal的一些调用。不是全部。相同的输入的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我使用javax.crypto.cipher加密和解密一些数据。
它运行良好。但有时，解密有一个badPaddingException。如果我将一个成功的调用与一个failling调用，给给密码的输入是相同的，并且密码以相同的方式初始化。
如何我instanciate我的密码
dcipher = Cipher.getInstance（PBEWithMD5AndDES）;
KeySpec keySpec = new PBEKeySpec（passPhrase.toCharArray（），salt，iterationCount）;
SecretKey key = SecretKeyFactory.getInstance（PBEWithMD5AndDES）。generateSecret（keySpec）;
dcipher.init（Cipher.DECRYPT_MODE，key，paramSpec）;
我使用它的方式
dec = Base64.decode（str）;
byte [] utf8 = dcipher.doFinal（dec）;
doFinal引发异常。
任何想法？
谢谢！
哦，btw，我使用bouncyCastle作为提供者，它位于列表顶部
Security.insertProviderAt（new org.bouncycastle.jce.provider.BouncyCastleProvider ;
为了完整性，并且因为问题仍然不时出现。这里是完整的类。
public class EncryptDecryptUtil {
/ **加密密码* /
private static Cipher ecipher;
/ **解密密码* /
私人静态密码解密;
private static Logger logger = Logger.getLogger（EncryptDecryptUtil.class）;
/ **
*用于创建此对象的构造函数。负责设置和初始化此对象的加密器和
* decrypter密码实例给出一个秘密密钥和算法。
*
* @param key Secret Key用于初始化encrypter和decrypter实例。
* @param algorithm用于创建encrypter和decrypter实例的算法。
* /
public EncryptDecryptUtil（SecretKey key，String algorithm）{
Security.insertProviderAt（new org.bouncycastle.jce.provider.BouncyCastleProvider（），1）;
try {
ecipher = Cipher.getInstance（algorithm）;
dcipher = Cipher.getInstance（algorithm）;
ecipher.init（Cipher.ENCRYPT_MODE，key）;
dcipher.init（Cipher.DECRYPT_MODE，key）;
} catch（NoSuchPaddingException e）{
System.out.println（EXCEPTION：NoSuchPaddingException）;
} catch（NoSuchAlgorithmException e）{
System.out.println（EXCEPTION：NoSuchAlgorithmException）;
} catch（InvalidKeyException e）{
System.out.println（EXCEPTION：InvalidKeyException）;
}
}
/ **
*用于创建此对象的构造函数。负责设置和初始化此对象的加密器和
* decrypter密码实例给出一个Pass Phrase和算法。
*
* @param passPhrase Pass用于初始化encrypter和decrypter实例的短语。
* /
public EncryptDecryptUtil（String passPhrase）{
Security.insertProviderAt（new org.bouncycastle.jce.provider.BouncyCastleProvider（），1）;
// 8字节Salt
byte [] salt = {（字节）0xB9，（字节）0x8B，（字节）0xD8，（字节）0x31，（字节）0x55， （字节）0xF3，（字节）0x13};
//迭代计数
int iterationCount = 19;
try {
//生成与密码短语相关的密钥。
KeySpec keySpec = new PBEKeySpec（passPhrase.toCharArray（），salt，iterationCount）;
SecretKey key = SecretKeyFactory.getInstance（PBEWithMD5AndDES）。generateSecret（keySpec）;
//获取密码实例
ecipher = Cipher.getInstance（PBEWithMD5AndDES）;
dcipher = Cipher.getInstance（PBEWithMD5AndDES）;
//准备参数到cipthers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec（salt，iterationCount）;
ecipher.init（Cipher.ENCRYPT_MODE，key，paramSpec）;
dcipher.init（Cipher.DECRYPT_MODE，key，paramSpec）;
} catch（InvalidAlgorithmParameterException e）{
logger.error（encrypter instantiation，e）;
} catch（InvalidKeySpecException e）{
logger.error（encrypter instantiation，e）;
} catch（NoSuchPaddingException e）{
logger.error（encrypter instantiation，e）;
} catch（NoSuchAlgorithmException e）{
logger.error（encrypter instantiation，e）;
} catch（InvalidKeyException e）{
logger.error（encrypter instantiation，e）;
}
}
/ **
*将单个String作为参数，并返回该字符串的加密版本。
*
* @param str要加密的字符串
* @return< code> String< / code>加密的版本的字符串
* /
public String encrypt（String str）{
try {
//使用utf-8将字符串编码为字节
byte [] utf8 = str.getBytes（UTF8）;
//加密
byte [] enc = ecipher.doFinal（utf8）;
//将字节编码为base64以获取字符串
return new String（Base64.encode（enc），UTF8）;
} catch（BadPaddingException e）{
logger.error（在加密期间：，e）;
} catch（IllegalBlockSizeException e）{
logger.error（在加密期间：，e）;
} catch（UnsupportedEncodingException e）{
logger.error（在加密期间：，e）;
}
return new String（）;
}
/ **
*将加密的String作为参数，解密并返回解密的String。
*
* @param str要解密的加密字符串
* @return< code> String< / code>提供的字符串的解密版本
* /
public String decrypt（String str）{
byte [] dec = new byte [0];
try {
//解码base64以获取字节。不知道为什么。
dec = Base64.decode（str）;
//解密
byte [] utf8 = dcipher.doFinal（dec）;
//使用utf-8解码
return new String（utf8，UTF8）;解码的字符串是：+ str +要解码的字节数组是：+ Arrays.toString（） dec），e）;
} catch（IllegalBlockSizeException e）{
logger.error（在解密期间：，e）;
} catch（UnsupportedEncodingException e）{
logger.error（在解密期间：，e）;
}
return new String（）;
}
}
编辑：
我想强调这2点：
- 相同的输入有时会失败/有时被成功解密。 （我知道感谢BadPaddingException的日志）
- 这个主要调用decrypt方法1 000 000 000次doest重现issus。
...
for（int i = 0; i <1000000000; i ++）{
EncryptDecryptUtil encryptDecript = new EncryptDecryptUtil（pass）;
if（！YES.equals（encryptDecript.decrypt（Q3qWLKo6yJY =）））{
System.out.println（Fail at call+ i）;
throw new InvalidParameterException（）;
}
}
也许它可能来自我使用EncryptDecryptUtils类？它是一个Spring bean的领域，一次。
解密时com.myStuff.dlm.cryptography.EncryptDecryptUtil错误。要解码的字符串是：Q3qWLKo6yJY =要解码的字节数组是：[114，52，-52，-54，82，87，124，84]
javax.crypto.BadPaddingException：给定最后块未正确填充
at com.sun.crypto.provider.SunJCE_f.b（DashoA13 * ..）
at com.sun.crypto.provider.SunJCE_f.b（DashoA13 * ..）
at com.sun .crypto.provider.SunJCE_ab.b（DashoA13 * ..）
在com.sun.crypto.provider.PBEWithMD5AndDESCipher.engineDoFinal（DashoA13 * ..）
在javax.crypto.Cipher.doFinal（DashoA13 * ..）
at com.dvidea.dlm.cryptography.EncryptDecryptUtil.decrypt（EncryptDecryptUtil.java:166）
<
$ b $ b
回答。
I use a javax.crypto.cipher for encrypt and decrypt some data. It's working well. But sometimes, the decryption faill with a badPaddingException. If i compare a succefull call with a failling call, the input given to the cipher are the same, and the cipher is initialised the same way.
that how i instanciate my cipher
dcipher = Cipher.getInstance("PBEWithMD5AndDES");
KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
That how i use it
dec = Base64.decode(str) ;
byte[] utf8 = dcipher.doFinal(dec);
The exception is raised on the doFinal.
Any idea ?
Thanks !
Oh, btw, i use bouncyCastle as a provider, and add it on top on the list with
Security.insertProviderAt(new org.bouncycastle.jce.provider.BouncyCastleProvider(), 1);
For the sake of the completeness, and because the problem still appeart from time to time. Here is the complete class.
public class EncryptDecryptUtil {
/** Encryption Cipher */
private static Cipher ecipher;
/** Decription Cipher */
private static Cipher dcipher;
private static Logger logger = Logger.getLogger(EncryptDecryptUtil.class);
/**
* Constructor used to create this object. Responsible for setting and initializing this object's encrypter and
* decrypter Cipher instances given a Secret Key and algorithm.
*
* @param key Secret Key used to initialize both the encrypter and decrypter instances.
* @param algorithm Which algorithm to use for creating the encrypter and decrypter instances.
*/
public EncryptDecryptUtil(SecretKey key, String algorithm) {
Security.insertProviderAt(new org.bouncycastle.jce.provider.BouncyCastleProvider(), 1);
try {
ecipher = Cipher.getInstance(algorithm);
dcipher = Cipher.getInstance(algorithm);
ecipher.init(Cipher.ENCRYPT_MODE, key);
dcipher.init(Cipher.DECRYPT_MODE, key);
} catch (NoSuchPaddingException e) {
System.out.println("EXCEPTION: NoSuchPaddingException");
} catch (NoSuchAlgorithmException e) {
System.out.println("EXCEPTION: NoSuchAlgorithmException");
} catch (InvalidKeyException e) {
System.out.println("EXCEPTION: InvalidKeyException");
}
}
/**
* Constructor used to create this object. Responsible for setting and initializing this object's encrypter and
* decrypter Chipher instances given a Pass Phrase and algorithm.
*
* @param passPhrase Pass Phrase used to initialize both the encrypter and decrypter instances.
*/
public EncryptDecryptUtil(String passPhrase) {
Security.insertProviderAt(new org.bouncycastle.jce.provider.BouncyCastleProvider(), 1);
// 8-bytes Salt
byte[] salt = { (byte) 0xB9, (byte) 0x8B, (byte) 0xD8, (byte) 0x31, (byte) 0x55, (byte) 0x24, (byte) 0xF3, (byte) 0x13 };
// Iteration count
int iterationCount = 19;
try {
// Generate the secret key associated to the passphrase.
KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
// Get instance of the cipher
ecipher = Cipher.getInstance("PBEWithMD5AndDES");
dcipher = Cipher.getInstance("PBEWithMD5AndDES");
// Prepare the parameters to the cipthers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
} catch (InvalidAlgorithmParameterException e) {
logger.error("during encrypter instantiation",e);
} catch (InvalidKeySpecException e) {
logger.error("during encrypter instantiation",e);
} catch (NoSuchPaddingException e) {
logger.error("during encrypter instantiation",e);
} catch (NoSuchAlgorithmException e) {
logger.error("during encrypter instantiation",e);
} catch (InvalidKeyException e) {
logger.error("during encrypter instantiation",e);
}
}
/**
* Takes a single String as an argument and returns an Encrypted version of that String.
*
* @param str String to be encrypted
* @return <code>String</code> Encrypted version of the provided String
*/
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new String( Base64.encode(enc), "UTF8");
} catch (BadPaddingException e) {
logger.error("during encryption : ",e);
} catch (IllegalBlockSizeException e) {
logger.error("during encryption : ",e);
} catch (UnsupportedEncodingException e) {
logger.error("during encryption : ",e);
}
return new String();
}
/**
* Takes a encrypted String as an argument, decrypts and returns the decrypted String.
*
* @param str Encrypted String to be decrypted
* @return <code>String</code> Decrypted version of the provided String
*/
public String decrypt(String str) {
byte[] dec = new byte[0];
try {
// Decode base64 to get bytes. Not sure to understand why.
dec = Base64.decode(str) ;
// Decrypt
byte[] utf8 = dcipher.doFinal(dec);
// Decode using utf-8
return new String(utf8, "UTF8");
} catch (BadPaddingException e) {
logger.error("error during decryption. String to decode was : "+str + " byte array to decode was : "+ Arrays.toString(dec) ,e);
} catch (IllegalBlockSizeException e) {
logger.error("during decryption : ",e);
} catch (UnsupportedEncodingException e) {
logger.error("during decryption : ",e);
}
return new String();
}
}
Edit : I would like to stress this 2 points :
- the same input will sometime fail / sometime be sucessfully decrypted. ( i know that thanks to the logs in the BadPaddingException )
- this main calling the decrypt method 1 000 000 000 times doest reproduce the issus.
...
for( int i = 0 ; i<1000000000 ; i++){
EncryptDecryptUtil encryptDecript = new EncryptDecryptUtil("pass");
if ( !"YES".equals(encryptDecript.decrypt("Q3qWLKo6yJY="))){
System.out.println("Fail at call " + i);
throw new InvalidParameterException() ;
}
}
So maybe it could come from the way i use the EncryptDecryptUtils class ? It's a field of a Spring bean, instancied one time.
com.myStuff.dlm.cryptography.EncryptDecryptUtil error during decryption. String to decode was : Q3qWLKo6yJY= byte array to decode was : [114, 52, -52, -54, 82, 87, 124, 84]
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.SunJCE_ab.b(DashoA13*..)
at com.sun.crypto.provider.PBEWithMD5AndDESCipher.engineDoFinal(DashoA13*..)
at javax.crypto.Cipher.doFinal(DashoA13*..)
at com.dvidea.dlm.cryptography.EncryptDecryptUtil.decrypt(EncryptDecryptUtil.java:166)
解决方案
Just an idea: Maybe you are jumping among different providers (Sun/BC/etc)
Regards.
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