Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded

本工具类经过测试可用，之前写的没有使用CipherInputStream和CipherOutputStream，生成的加密文件与源文件大小不一致，加密时没有问题，解密时总是抛出如下异常：

Exception in thread " main " 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 *.. )

其中BASE64底层依赖库没有使用SUN的，而是下载的“javabase64-1.3.1.jar”

DESUtils.java

package demo.security;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/** */ /**
* 
* DES加密解密工具包
* 
*
* @author IceWee
* @date 2012-5-19
* @version 1.0
*/
public class DESUtils

{

 private static final String ALGORITHM = "DES";
 private static final int CACHE_SIZE = 1024;

 /** *//**
 * 
 * 生成随机密钥
 * 
 *
 * @return
 * @throws Exception
 */
 public static String getSecretKey() throws Exception

{
 return getSecretKey(null);
 }

 /** *//**
 * 
 * 生成密钥
 * 
 *
 * @param seed 密钥种子
 * @return
 * @throws Exception
 */
 public static String getSecretKey(String seed) throws Exception

{
 SecureRandom secureRandom;
 if (seed != null && !"".equals(seed))
 secureRandom = new SecureRandom(seed.getBytes());
 else
 secureRandom = new SecureRandom();
 KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
 keyGenerator.init(secureRandom);
 SecretKey secretKey = keyGenerator.generateKey();
 return Base64Utils.encode(secretKey.getEncoded());
 }

 /** *//**
 * 
 * 加密
 * 
 *
 * @param data
 * @param key
 * @return
 * @throws Exception
 */
 public static byte[] encrypt(byte[] data, String key) throws Exception

{
 Key k = toKey(Base64Utils.decode(key));
 Cipher cipher = Cipher.getInstance(ALGORITHM);
 cipher.init(Cipher.ENCRYPT_MODE, k);
 return cipher.doFinal(data);
 }

 /** *//**
 * 
 * 文件加密
 * 
 *
 * @param key
 * @param sourceFilePath
 * @param destFilePath
 * @throws Exception
 */
 public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception

{
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile())

{
if (!destFile.getParentFile().exists())

{
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, k);
            CipherInputStream cin = new CipherInputStream(in, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = cin.read(cache)) != -1)

{
 out.write(cache, 0, nRead);
 out.flush();
 }
 out.close();
 cin.close();
 in.close();
 }
 }

 /** *//**
 * 
 * 解密
 * 
 *
 * @param data
 * @param key
 * @return
 * @throws Exception
 */
 public static byte[] decrypt(byte[] data, String key) throws Exception

{
 Key k = toKey(Base64Utils.decode(key));
 Cipher cipher = Cipher.getInstance(ALGORITHM);
 cipher.init(Cipher.DECRYPT_MODE, k);
 return cipher.doFinal(data);
 }

 /** *//**
 * 
 * 文件解密
 * 
 *
 * @param key
 * @param sourceFilePath
 * @param destFilePath
 * @throws Exception
 */
 public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception

{
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile())

{
if (!destFile.getParentFile().exists())

{
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, k);
            CipherOutputStream cout = new CipherOutputStream(out, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1)

{
 cout.write(cache, 0, nRead);
 cout.flush();
 }
 cout.close();
 out.close();
 in.close();
 }
 }

 /** *//**
 * 
 * 转换密钥
 * 
 *
 * @param key
 * @return
 * @throws Exception
 */
 private static Key toKey(byte[] key) throws Exception

{
        DESKeySpec dks = new DESKeySpec(key);
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
        SecretKey secretKey = keyFactory.generateSecret(dks);
        return secretKey;
    }

}

Base64Utils.java

package demo.security;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import it.sauronsoftware.base64.Base64;

/** */ /**

*

* BASE64编码解码工具包

*

*

* 依赖javabase64-1.3.1.jar

*

* @author IceWee

* @date 2012-5-19

* @version 1.0

public class Base64Utils

{

/** *//**

* 文件读取缓冲区大小

private static final int CACHE_SIZE = 1024;

/** *//**

*

* BASE64字符串解码为二进制数据

*

* @param base64

* @return

* @throws Exception

public static byte[] decode(String base64) throws Exception

{

return Base64.decode(base64.getBytes());

}

/** *//**

*

* 二进制数据编码为BASE64字符串

*

* @param bytes

* @return

* @throws Exception

public static String encode(byte[] bytes) throws Exception

{

return new String(Base64.encode(bytes));

}

/** *//**

*

* 将文件编码为BASE64字符串

*

*

* 大文件慎用，可能会导致内存溢出

*

* @param filePath 文件绝对路径

* @return

* @throws Exception

public static String encodeFile(String filePath) throws Exception

{

byte[] bytes = fileToByte(filePath);

return encode(bytes);

}

/** *//**

*

* BASE64字符串转回文件

*

* @param filePath 文件绝对路径

* @param base64 编码字符串

* @throws Exception

public static void decodeToFile(String filePath, String base64) throws Exception

{

byte[] bytes = decode(base64);

byteArrayToFile(bytes, filePath);

}

/** *//**

*

* 文件转换为二进制数组

*

* @param filePath 文件路径

* @return

* @throws Exception

public static byte[] fileToByte(String filePath) throws Exception

{

byte[] data = new byte[0];

File file = new File(filePath);

if (file.exists())

{

FileInputStream in = new FileInputStream(file);

ByteArrayOutputStream out = new ByteArrayOutputStream(2048);

byte[] cache = new byte[CACHE_SIZE];

int nRead = 0;

while ((nRead = in.read(cache)) != -1)

{

out.write(cache, 0, nRead);

out.flush();

}

out.close();

in.close();

data = out.toByteArray();

}

return data;

}

/** *//**

*

* 二进制数据写文件

*

* @param bytes 二进制数据

* @param filePath 文件生成目录

public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception

{

InputStream in = new ByteArrayInputStream(bytes);

File destFile = new File(filePath);

if (!destFile.getParentFile().exists())

{

destFile.getParentFile().mkdirs();

}

destFile.createNewFile();

OutputStream out = new FileOutputStream(destFile);

byte[] cache = new byte[CACHE_SIZE];

int nRead = 0;

while ((nRead = in.read(cache)) != -1)

{

out.write(cache, 0, nRead);

out.flush();

}

out.close();

in.close();

}

DESTester.java

package demo.security;

public class DESTester

{

static String key;

static

{

try

{

key = DESUtils.getSecretKey();

} catch (Exception e)

{

e.printStackTrace();

}

public static void main(String[] args) throws Exception

{

long begin = System.currentTimeMillis();

encryptFile();

decryptFile();

test();

long end = System.currentTimeMillis();

System.err.println("耗时：" + (end-begin)/1000 + "秒

");

}

static void encryptFile() throws Exception

{

String sourceFilePath = "D:/demo.mp4";

String destFilePath = "D:/demo_encrypted.mp4";

DESUtils.encryptFile(key, sourceFilePath, destFilePath);

}

static void decryptFile() throws Exception

{

String sourceFilePath = "D:/demo_encrypted.mp4";

String destFilePath = "D:/demo_decrypted.mp4";

DESUtils.decryptFile(key, sourceFilePath, destFilePath);

}

static void test() throws Exception

{

String source = "这是一行测试DES加密/解密的文字，你看完也等于没看，是不是啊？！";

System.err.println("原文:\t" + source);

byte[] inputData = source.getBytes();

inputData = DESUtils.encrypt(inputData, key);

System.err.println("加密后:\t" + Base64Utils.encode(inputData));

byte[] outputData = DESUtils.decrypt(inputData, key);

String outputStr = new String(outputData);

System.err.println("解密后:\t" + outputStr);

}

Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded

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