私は、SharedPreferencesに保存されているEditText文字列の暗号化と復号化の支援が必要な初心者のAndroidプログラマーです。これは非常に一般的な手順であり、これを達成する方法をカバーする多くのチュートリアルがあるはずですが、私は非常に良い情報やガイダンスを見つけられませんでした。ここに記載されている手順に従いましたが、 xml ファイルを確認するとデータがクリアテキストで表示されます。どんな助けでも大歓迎です。
クラスはEditText文字列を受け取り、以下をエンコードします。
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;
}
}
復号化と比較に使用されるクラス：
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);
}
}