我正在尝试加密我的python Web服务器中的一些文件，并在下载后在android应用程序中解密它们。我使用了python AES encryption java decryption这样的问题方法但我在android代码中得到了填充异常我该怎么办？ 我的python代码：
from Crypto.Cipher import AES
import os, random, struct
key = '0123456789abcdef'
mode = AES.MODE_CBC
chunksize = 64*1024
iv = ''.join(chr(random.randint(0,0xFF)) for i in range(16))
encryptor = AES.new(key,mode,iv)
filesize = os.path.getsize('sample.jpg')
with open('sample.jpg','rb') as infile:
with open('sample.enc','wb') as outfile:
outfile.write(struct.pack('<Q',filesize))
outfile.write(iv)
while True:
chunk = infile.read(chunksize)
if len(chunk) == 0:
break
elif len(chunk) % 16 != 0:
chunk += ' ' * (16 - len(chunk) % 16)
outfile.write(encryptor.encrypt(chunk))
## decrypt
with open('sample.enc', 'rb') as infile:
origsize = struct.unpack('<Q', infile.read(struct.calcsize('Q')))[0]
iv = infile.read(16)
print('test',iv.hexdigest())
decryptor = AES.new(key, AES.MODE_CBC, iv)
with open('sample2.jpg', 'wb') as outfile:
while True:
chunk = infile.read(chunksize)
if len(chunk) == 0:
break
outfile.write(decryptor.decrypt(chunk))
outfile.truncate(origsize)
和android代码：
package com.example.crypto;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.os.Build;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button encryptButton = (Button) findViewById(R.id.button1);
Button DecryptButton = (Button) findViewById(R.id.button2);
encryptButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
try {
encrypt();
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchPaddingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
public void decryptFile(){
String inFile = "sample.enc";
String outFile = "sample.jpg";
String dir = Environment.getExternalStorageDirectory() +"/Books/";
InputStream is = null ;
byte[] filesize = new byte[8];
byte[] iv = new byte[16];
try {
is = new FileInputStream(dir+inFile);
is.read(filesize);
is.read(iv);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
Log.d("D1","no file found");
} catch (IOException e) {
// TODO Auto-generated catch block
Log.d("D-2","no file found");
e.printStackTrace();
}
byte[] k = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};
Key key = new SecretKeySpec(k,"AES");
try {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(iv));
OutputStream outs = new FileOutputStream(dir+outFile);
//is = new FileInputStream(dir+inFile);
while(true){
byte[] chunk = new byte[64*1024];
is.read(chunk);
if(chunk.length == 0){
break;
}
outs.write(cipher.doFinal(chunk));
}
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
Log.d("D","1");
e.printStackTrace();
} catch (NoSuchPaddingException e) {
// TODO Auto-generated catch block
Log.d("D","2");
e.printStackTrace();
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
Log.d("D","3");
e.printStackTrace();
} catch (InvalidAlgorithmParameterException e) {
// TODO Auto-generated catch block
Log.d("D","4");
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Log.d("D","5");
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
Log.d("D","6");
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
// TODO Auto-generated catch block
Log.d("D","7");
e.printStackTrace();
} catch (BadPaddingException e) {
// TODO Auto-generated catch block
Log.d("D","8");
e.printStackTrace();
}
}
我在基本代码中修复了一些错误，如文件大小和...但仍存在填充问题。在python中解密我们使用文件大小并截断文件，但在java中我不知道如何做到这一点！