javax.crypto base64需要帮助

Question

我是一名新手Android程序员，需要加密和解密存储在共享Preference中的EditText字符串。这似乎应该是一个非常普遍的程序，应该有许多教程涵盖如何完成此操作，但我没有找到很好的信息或指导。我遵循此处给出的说明，但是在检查XML文件时，我的数据显示在清晰的文本中。任何帮助将不胜感激。

类接收EditText字符串和编码：

private SharedPreferences sp;

Intent i;
Button regBttn,rtnBttn;
EditText rName,rPwd;
String user, pass, chk;
String stat="a";
String key = "N@!an@jajpn!==";

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{

     super.onCreate(savedInstanceState);
     setContentView(R.layout.register);
    rName=(EditText)findViewById(R.id.reg_uname);
    rPwd=(EditText)findViewById(R.id.reg_pswd);
    regBttn=(Button)findViewById(R.id.reg_button);
    rtnBttn=(Button)findViewById(R.id.rtn_button); 
    regBttn.setOnClickListener(this);
    rtnBttn.setOnClickListener(this);
    sp=this.getSharedPreferences("AccessApp", MODE_WORLD_READABLE);
    chk=sp.getString("USERNAME_KEY", "");
    if(chk.length()!=0){
    sp=getSharedPreferences("AccessApp",MODE_WORLD_WRITEABLE); 
    i=new Intent(this,AccessApp.class);
    startActivity(i); 
    }     
   }
public void onClick(View arg0) {
    user=rName.getText().toString().trim();
    pass=rPwd.getText().toString().trim();
    if(arg0==regBttn){     
       if((user.length()!=0))
        {
         if((pass.length()!=0))
            {
        sp=getSharedPreferences("AccessApp",MODE_WORLD_WRITEABLE);
        Editor myEditor=sp.edit();
        try {
            byte[ ] superSecretKeyBytes = Base64.decode(user);
            byte[] key = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6 };
            for (int i = 0; i < superSecretKeyBytes.length && i < key.length; i++) {
                key[i] = superSecretKeyBytes[i];
                myEditor.putString("USERNAME_KEY", user);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
        try {
            byte[ ] superSecretKeyBytes = Base64.decode(pass);
            byte[] key = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6 };
            for (int i = 0; i < superSecretKeyBytes.length && i < key.length; i++) {
                key[i] = superSecretKeyBytes[i];
                myEditor.putString("PASSWORD_KEY", pass);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        myEditor.commit();
        Toast.makeText(this, "Registration is successfull",10000).show();
        i=new Intent(this,AccessApp.class);
        startActivity(i);
        }
        else
         {
          Toast.makeText(this, "Please Enter password", 10000).show();  
         }
         }
        else{
            Toast.makeText(this,"Please Enter Username",10000).show();
         }
        }
    else if(arg0==rtnBttn){
        AlertDialog.Builder builder=new AlertDialog.Builder(this);
         builder.setTitle("Exit");
         builder.setMessage("Do you want to exit");
         builder.setCancelable(false);
         builder.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int which) {
  // TODO Auto-generated method stub
  finish();
  }
  });
    builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
               arg0.cancel();
            }
        });
    AlertDialog alert=builder.create();
    alert.show();
    }
}
public String encrypt(String toencrypt, byte key[]) throws Exception {
    SecretKeySpec secret = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, secret);
    byte[] encryptedbytes = cipher.doFinal(toencrypt.getBytes());
    String encrypted = Base64.encodeBytes(encryptedbytes, 0);
    return encrypted;
}
}

用于解密和比较的类：

public class AccessApp extends Activity implements OnClickListener {
private SharedPreferences sp;
String user,pass;
Button lBttn,cBttn;
EditText uname,pword;
Intent i;
int flag=0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{ 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    lBttn=(Button)findViewById(R.id.login_button);
    cBttn=(Button)findViewById(R.id.cancel_button);
    uname=(EditText)findViewById(R.id.username);
    pword=(EditText)findViewById(R.id.password);
    lBttn.setOnClickListener(this);
    cBttn.setOnClickListener(this);
}
public void onClick(View arg0) {
    sp=this.getSharedPreferences("AccessApp", MODE_WORLD_READABLE);
    user = sp.getString("USERNAME_KEY", "");
    pass = sp.getString("PASSWORD_KEY", "");


   if(lBttn.equals(arg0)){
      if((uname.getText().toString().equals(user))&& 
        (pword.getText().toString().equals(pass)))
            {
          Toast.makeText(this, "You are Logged In", 20000).show();
               Intent intent;
               intent=new Intent(this,details.class);
               startActivity(intent);
              flag=1;
            }
        else 
           {
            Toast.makeText(this, "Wrong Username or Password",20000).show();
            flag=0;   
           }       
        } 
        else if(cBttn==arg0){
            AlertDialog.Builder builder=new AlertDialog.Builder(this);
          builder.setTitle("Exit");
         builder.setMessage("Do you want to exit");
    builder.setCancelable(false);
    builder.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
 public void onClick(DialogInterface dialog, int which) {
 // TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
 finish();
 }
 });
    builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
               arg0.cancel();
            }
        });
    AlertDialog alert=builder.create();
    alert.show();
        }
    }
@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
 if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
     Intent intent = new Intent(Intent.ACTION_MAIN);
        intent.addCategory(Intent.CATEGORY_HOME);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
     finish();
 }
 return super.onKeyDown(keyCode, event);
}
public static String decrypt(String encryptedText, byte[ ] key) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    byte[] toDecrypt = Base64.decode(encryptedText);
    byte[] encrypted = cipher.doFinal(toDecrypt);
    return new String(encrypted);
}
}

Answer 1

您似乎将未加密的用户名和密码保存到编辑器：

        byte[ ] superSecretKeyBytes = Base64.decode(pass);  
        byte[] key = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6 };
        for (int i = 0; i < superSecretKeyBytes.length && i < key.length; i++) {
            key[i] = superSecretKeyBytes[i];
            myEditor.putString("PASSWORD_KEY", pass);
        }

说实话，我不知道为什么要这样做。您实际上所做的似乎确实是不必要的，因为您将其解码为字节数组，创建固定的字节阵列，通过解码阵列循环，并用解码的一个替换了创建的固定量阵列的数据，然后然后将未更改的字符串密码添加到编辑器（您要做的太多次，顺便说一句）。而且我很确定那不是您要做的。

我相信您想做的是实际上是加密的，但是您永远不会到达它，所以让我们尝试一下：

首先，您的密钥应该是一个静态变量，就好像发生变化一样，它将不再能够适当地加密/解密。

byte[] key = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6 };

现在，基于您已经拥有的内容加密密码，请根据您的秘密密钥调用加密方法（在这种情况下：键）和要加密的字符串（在这种情况下：Pass）：

String encryptedPassword = encrypt(pass, key);

现在，EncryptedPassword基于输入的密钥包含密码的base64加密形式。现在，剩下要做的就是将密码的加密形式保存在编辑器中，而不是像以前这样做的未加密表格。

myEditor.putString("PASSWORD_KEY", encryptedPassword);

现在，当您致电myeditor.commit（）时，您将存储加密的表单。

这是第一个源文件中的用户名和密码加密的编辑onClick方法。我没有看你的解密部分，但是您应该能够根据我给您的东西来弄清楚它：

public void onClick(View arg0) {
    user=rName.getText().toString().trim();
    pass=rPwd.getText().toString().trim();
    if(arg0==regBttn){     
       if((user.length()!=0))
        {
          if((pass.length()!=0))
        {
        sp=getSharedPreferences("AccessApp",MODE_WORLD_WRITEABLE);
        Editor myEditor=sp.edit();
        byte[] key = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6 };
        try {
             String encryptedUser = encrypt(user, key);  
             myEditor.putString("USERNAME_KEY", encryptedUser); 
        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }   
    try {
             String encryptedPass = encrypt(pass, key);  
             myEditor.putString("PASSWORD_KEY", encryptedPass); 
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    myEditor.commit();
    Toast.makeText(this, "Registration is successfull",10000).show();
    i=new Intent(this,AccessApp.class);
    startActivity(i);
    }
    else
     {
      Toast.makeText(this, "Please Enter password", 10000).show();  
     }
     }
    else{
        Toast.makeText(this,"Please Enter Username",10000).show();
     }
    }
else if(arg0==rtnBttn){
    AlertDialog.Builder builder=new AlertDialog.Builder(this);
     builder.setTitle("Exit");
     builder.setMessage("Do you want to exit");
     builder.setCancelable(false);
     builder.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int which) {
  // TODO Auto-generated method stub
  finish();
  }
  });
    builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                arg0.cancel();
            }
        });
    AlertDialog alert=builder.create();
    alert.show();
    }
}

希望它有助于〜