我正在创建加密和解密字符串的android应用程序我正在使用密码算法应用程序与加密工作正常但当我尝试解密系统时显示错误：
01-10 09:50:54.364: E/AndroidRuntime(602): Caused by: javax.crypto.IllegalBlockSizeException: last block incomplete in decryption
任何人都可以帮我解决这个错误吗？
package com.devleb.encdecapp;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import android.app.Activity;
import android.os.Bundle;
import android.util.Base64;
import android.util.Log;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
public class MainActivity extends Activity implements OnClickListener {
// views for the layout
Spinner spin;
EditText edit_txt_pass;
static EditText edit_txt_enc_string;
EditText edit_txt_raw;
static EditText edit_txt_dec_string;
Button btn_encrypt, btn_decrypt, btn_clear;
static String cyphertext = "";
static String STReditTxtPass;
String strPaddingencryption;
static int iterations = 1000;
private static final String[] items = { "Padding Key derivation",
"SHA1PRNG key derivation", "PBKDF2 key derivation",
"PKCS#12 key derivation" };
private static final String TAG = MainActivity.class.getSimpleName();
private static final String[] Passwords = { "password", "cryptography",
"cipher", "algorithm", "qwerty" };
// mesage that will be binded with the key to generate the cypher text
private static String PlainText = "this is the text that will be encrypted";
// the list that will be used for the OnItemSelection method
private static final int PADDING_ENC_IDX = 0;
private static final int SHA1PRNG_ENC_IDX = 1;
private static final int PBKDF2_ENC_IDX = 2;
private static final int PKCS12_ENC_IDX = 3;
byte[] salt = { (byte) 0x11, (byte) 0x9B, (byte) 0xC6, (byte) 0xFE,
(byte) 0x33, (byte) 0x44, (byte) 0x55, (byte) 0x77 };;
static byte[] ivBytes = {0,0,0,0,0,0,0,0};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// creation of the spinner with setting Array adapter and
// DropDownresourse
spin = (Spinner) findViewById(R.id.spiner);
spin.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
// TODO Auto-generated method stub
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
ArrayAdapter<String> aa = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, items);
aa.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
spin.setAdapter(aa);
// end of the spinner code
edit_txt_pass = (EditText) findViewById(R.id.editTxtPass);
edit_txt_enc_string = (EditText) findViewById(R.id.editTxtEncString);
edit_txt_raw = (EditText) findViewById(R.id.editTxtRawKey);
edit_txt_dec_string = (EditText) findViewById(R.id.editTxtDecString);
btn_encrypt = (Button) findViewById(R.id.btnEncrypt);
btn_encrypt.setOnClickListener(this);
btn_decrypt = (Button) findViewById(R.id.btnDecrypt);
btn_decrypt.setOnClickListener(this);
btn_clear = (Button) findViewById(R.id.btnClear);
btn_clear.setOnClickListener(this);
// / for registering the editText to the Context Menu
registerForContextMenu(edit_txt_pass);
}
// for the ciphering of the plainText using the base 64
public static String toBase64(byte[] bytes) {
return Base64.encodeToString(bytes, Base64.NO_WRAP);
}
public static byte[] fromBase64(byte[] bytes) {
// return Base64.encodeToString(bytes, Base64.NO_WRAP);
return Base64.decode(bytes, Base64.DEFAULT);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
// TODO Auto-generated method stub
int groupId = 0;
menu.add(groupId, 1, 1, "password");
menu.add(groupId, 2, 2, "cryptography");
menu.add(groupId, 3, 3, "cipher");
menu.add(groupId, 4, 4, "algorithm");
menu.add(groupId, 5, 5, "qwerty");
super.onCreateContextMenu(menu, v, menuInfo);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
// TODO Auto-generated method stub
return getText(item);
// return super.onContextItemSelected(item);
}
private boolean getText(MenuItem item) {
// TODO Auto-generated method stub
int menuItemId = item.getItemId();
if (menuItemId == 1) {
edit_txt_pass.setText("password");
}
if (menuItemId == 2) {
edit_txt_pass.setText("cryptography");
}
if (menuItemId == 3) {
edit_txt_pass.setText("cipher");
}
if (menuItemId == 4) {
edit_txt_pass.setText("algorithm");
}
if (menuItemId == 5) {
edit_txt_pass.setText("qwerty");
}
STReditTxtPass = edit_txt_pass.getText().toString();
Log.w("the String of the Password text", STReditTxtPass);
return false;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v == btn_encrypt) {
encryptPadding(PlainText, salt);
} else if (v == btn_clear) {
edit_txt_enc_string.setText("");
} else if (v == btn_decrypt) {
decryptPadding(cyphertext, salt);
}
}
public static String encryptPadding(String plaintext, byte[] salt) {
try {
KeyGenerator kg = KeyGenerator.getInstance("DES");
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
SecretKey SKey = kg.generateKey();
cipher.init(Cipher.ENCRYPT_MODE, SKey);
byte[] cipherText = cipher.doFinal(PlainText.getBytes("UTF-8"));
cyphertext = String.format("%s%s%s", toBase64(salt), "]",
toBase64(cipherText));
edit_txt_enc_string.setText(cyphertext);
return cyphertext;
} catch (GeneralSecurityException e) {
throw new RuntimeException(e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
public static String decryptPadding(String ctext, byte[] salt) {
try {
KeyGenerator kg = KeyGenerator.getInstance("DES");
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
SecretKey SKey = kg.generateKey();
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
cipher.init(Cipher.DECRYPT_MODE, SKey, ivSpec);
byte[] plaintxt = cipher.doFinal(cyphertext.getBytes("UTF-8"));
PlainText = String.format("%s%s%s", fromBase64(salt), "]",
fromBase64(plaintxt));
edit_txt_dec_string.setText(PlainText);
return PlainText;
} catch (GeneralSecurityException e) {
throw new RuntimeException(e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
}
答案 0 :(得分：3)
您必须使用相同的密钥进行解密和加密
SecretKey SKey = kg.generateKey();
这为两个操作创建了一个新密钥。您需要使用相同的密钥。
更改以下方法：
public String encryptPadding(String plaintext, byte[] salt) {
try {
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, SKey);
byte[] cipherText = cipher.doFinal(PlainText.getBytes("UTF-8"));
cyphertext = String.format("%s%s%s", toBase64(salt), "]",
toBase64(cipherText));
edit_txt_enc_string.setText(cyphertext);
return cyphertext;
} catch (GeneralSecurityException e) {
throw new RuntimeException(e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
public String decryptPadding(String ctext, byte[] salt) {
try {
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
cipher.init(Cipher.DECRYPT_MODE, SKey, ivSpec);
byte[] plaintxt = cipher.doFinal(cyphertext.getBytes("UTF-8"));
PlainText = String.format("%s%s%s", fromBase64(salt), "]",
fromBase64(plaintxt));
edit_txt_dec_string.setText(PlainText);
return PlainText;
} catch (GeneralSecurityException e) {
throw new RuntimeException(e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
在班级中创建一个新字段：
private SecretKey SKey;
并在onCreate方法中添加以下行：
KeyGenerator kg = KeyGenerator.getInstance("DES");
SKey = kg.generateKey();