Android杂谈---用MD5加密算法加密密码
2011-11-29 14:05
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很多的网络相关的软件都需要用户名密码登录,在开发的时候像这些密码都是保存在SharedPreferences中,这些密码保存在/data/data/包名/shared_prefs下,保存在一个XML文件中,如下:
可以用FileBrower查看
开始说道正题,MD5加密算法虽然现在有些人已经将其解开了,但是它的加密机制依然很强大,我想绝大对数还是不会解开的。MD5加密算法是单向加密,只能用你的密码才能解开,要不就是会解密算法,否则想都别想解开。为了防止这种情况的发生。还可以对加密过的密码进行再次加密。
下面是个小例子:
main.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<EditText
android:id="@+id/username"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="20dp"
android:layout_marginRight="10dp"
android:hint="帐号"
/>
<EditText
android:id="@+id/password"
android:password="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:hint="密码"
/>
<Button
android:id="@+id/save"
android:text="保存"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
/>
<Button
android:id="@+id/login"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:text="登录"
/>
</LinearLayout>
login.xml
Java代码
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="login successful!" /> </LinearLayout>
login.java
Java代码
package com.loulijun.md5demo;
import android.app.Activity;
import android.os.Bundle;
public class Login extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
}
}
MD5Demo.java
Java代码
package com.loulijun.md5demo;
import java.security.MessageDigest;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MD5Demo extends Activity {
private EditText username,password;
private Button savebtn,loginbtn;
String user,pass;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
username = (EditText)findViewById(R.id.username);
password = (EditText)findViewById(R.id.password);
savebtn = (Button)findViewById(R.id.save);
loginbtn = (Button)findViewById(R.id.login);
savebtn.setOnClickListener(new Button.OnClickListener()
{
@Override
public void onClick(View v) {
SharedPreferences pre = getSharedPreferences("loginvalue",MODE_WORLD_WRITEABLE);
pass = MD5(password.getText().toString());
user = username.getText().toString();
if(!pass.equals("")&&!user.equals(""))
{
pre.edit().putString("username", username.getText().toString()).
putString("password",encryptmd5(pass)).commit();
Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show();
}else
{
Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show();
}
}
});
loginbtn.setOnClickListener(new Button.OnClickListener()
{
@Override
public void onClick(View v) {
SharedPreferences sp = getSharedPreferences("loginvalue", MODE_WORLD_READABLE);
String loginuser = sp.getString("username", null);
String loginpass = sp.getString("password", null);
user = username.getText().toString();
pass = password.getText().toString();
String passmd5 = MD5(pass);
String encryptmd5 = encryptmd5(passmd5);
System.out.println("username="+loginuser+"-------------password="+loginpass);
System.out.println("user=="+user+"-------------encryptmd5=="+encryptmd5);
if(!user.equals("")&&!pass.equals(""))
{
if( user.equals(loginuser)&& encryptmd5.equals(loginpass))
{
Intent intent = new Intent();
intent.setClass(MD5Demo.this, Login.class);
MD5Demo.this.startActivity(intent);
finish();
}else
{
Toast.makeText(getApplicationContext(), "密码是错误的!", Toast.LENGTH_LONG).show();
}
}else
{
Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show();
}
}
});
}
//MD5加密,32位
public static String MD5(String str)
{
MessageDigest md5 = null;
try
{
md5 = MessageDigest.getInstance("MD5");
}catch(Exception e)
{
e.printStackTrace();
return "";
}
char[] charArray = str.toCharArray();
byte[] byteArray = new byte[charArray.length];
for(int i = 0; i < charArray.length; i++)
{
byteArray[i] = (byte)charArray[i];
}
byte[] md5Bytes = md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for( int i = 0; i < md5Bytes.length; i++)
{
int val = ((int)md5Bytes[i])&0xff;
if(val < 16)
{
hexValue.append("0");
}
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
// 可逆的加密算法
public static String encryptmd5(String str) {
char[] a = str.toCharArray();
for (int i = 0; i < a.length; i++)
{
a[i] = (char) (a[i] ^ 'l');
}
String s = new String(a);
return s;
}
}
程序很简单,下面是运行的效果:
大小: 9.2 KB
大小: 14.7 KB
大小: 24 KB
大小: 6.8 KB
查看图片附件
可以用FileBrower查看
开始说道正题,MD5加密算法虽然现在有些人已经将其解开了,但是它的加密机制依然很强大,我想绝大对数还是不会解开的。MD5加密算法是单向加密,只能用你的密码才能解开,要不就是会解密算法,否则想都别想解开。为了防止这种情况的发生。还可以对加密过的密码进行再次加密。
下面是个小例子:
main.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<EditText
android:id="@+id/username"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="20dp"
android:layout_marginRight="10dp"
android:hint="帐号"
/>
<EditText
android:id="@+id/password"
android:password="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:hint="密码"
/>
<Button
android:id="@+id/save"
android:text="保存"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
/>
<Button
android:id="@+id/login"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:text="登录"
/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <EditText android:id="@+id/username" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginLeft="10dp" android:layout_marginTop="20dp" android:layout_marginRight="10dp" android:hint="帐号" /> <EditText android:id="@+id/password" android:password="true" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginLeft="10dp" android:layout_marginTop="10dp" android:layout_marginRight="10dp" android:hint="密码" /> <Button android:id="@+id/save" android:text="保存" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginLeft="10dp" android:layout_marginTop="10dp" android:layout_marginRight="10dp" /> <Button android:id="@+id/login" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginLeft="10dp" android:layout_marginTop="10dp" android:layout_marginRight="10dp" android:text="登录" /> </LinearLayout>
login.xml
Java代码
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="login successful!" /> </LinearLayout>
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="login successful!" /> </LinearLayout>
login.java
Java代码
package com.loulijun.md5demo;
import android.app.Activity;
import android.os.Bundle;
public class Login extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
}
}
package com.loulijun.md5demo; import android.app.Activity; import android.os.Bundle; public class Login extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.login); } }
MD5Demo.java
Java代码
package com.loulijun.md5demo;
import java.security.MessageDigest;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MD5Demo extends Activity {
private EditText username,password;
private Button savebtn,loginbtn;
String user,pass;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
username = (EditText)findViewById(R.id.username);
password = (EditText)findViewById(R.id.password);
savebtn = (Button)findViewById(R.id.save);
loginbtn = (Button)findViewById(R.id.login);
savebtn.setOnClickListener(new Button.OnClickListener()
{
@Override
public void onClick(View v) {
SharedPreferences pre = getSharedPreferences("loginvalue",MODE_WORLD_WRITEABLE);
pass = MD5(password.getText().toString());
user = username.getText().toString();
if(!pass.equals("")&&!user.equals(""))
{
pre.edit().putString("username", username.getText().toString()).
putString("password",encryptmd5(pass)).commit();
Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show();
}else
{
Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show();
}
}
});
loginbtn.setOnClickListener(new Button.OnClickListener()
{
@Override
public void onClick(View v) {
SharedPreferences sp = getSharedPreferences("loginvalue", MODE_WORLD_READABLE);
String loginuser = sp.getString("username", null);
String loginpass = sp.getString("password", null);
user = username.getText().toString();
pass = password.getText().toString();
String passmd5 = MD5(pass);
String encryptmd5 = encryptmd5(passmd5);
System.out.println("username="+loginuser+"-------------password="+loginpass);
System.out.println("user=="+user+"-------------encryptmd5=="+encryptmd5);
if(!user.equals("")&&!pass.equals(""))
{
if( user.equals(loginuser)&& encryptmd5.equals(loginpass))
{
Intent intent = new Intent();
intent.setClass(MD5Demo.this, Login.class);
MD5Demo.this.startActivity(intent);
finish();
}else
{
Toast.makeText(getApplicationContext(), "密码是错误的!", Toast.LENGTH_LONG).show();
}
}else
{
Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show();
}
}
});
}
//MD5加密,32位
public static String MD5(String str)
{
MessageDigest md5 = null;
try
{
md5 = MessageDigest.getInstance("MD5");
}catch(Exception e)
{
e.printStackTrace();
return "";
}
char[] charArray = str.toCharArray();
byte[] byteArray = new byte[charArray.length];
for(int i = 0; i < charArray.length; i++)
{
byteArray[i] = (byte)charArray[i];
}
byte[] md5Bytes = md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for( int i = 0; i < md5Bytes.length; i++)
{
int val = ((int)md5Bytes[i])&0xff;
if(val < 16)
{
hexValue.append("0");
}
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
// 可逆的加密算法
public static String encryptmd5(String str) {
char[] a = str.toCharArray();
for (int i = 0; i < a.length; i++)
{
a[i] = (char) (a[i] ^ 'l');
}
String s = new String(a);
return s;
}
}
package com.loulijun.md5demo; import java.security.MessageDigest; import android.app.Activity; import android.content.Intent; import android.content.SharedPreferences; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class MD5Demo extends Activity { private EditText username,password; private Button savebtn,loginbtn; String user,pass; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); username = (EditText)findViewById(R.id.username); password = (EditText)findViewById(R.id.password); savebtn = (Button)findViewById(R.id.save); loginbtn = (Button)findViewById(R.id.login); savebtn.setOnClickListener(new Button.OnClickListener() { @Override public void onClick(View v) { SharedPreferences pre = getSharedPreferences("loginvalue",MODE_WORLD_WRITEABLE); pass = MD5(password.getText().toString()); user = username.getText().toString(); if(!pass.equals("")&&!user.equals("")) { pre.edit().putString("username", username.getText().toString()). putString("password",encryptmd5(pass)).commit(); Toast.makeText(getApplicationContext(), "保存成功!", Toast.LENGTH_SHORT).show(); }else { Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show(); } } }); loginbtn.setOnClickListener(new Button.OnClickListener() { @Override public void onClick(View v) { SharedPreferences sp = getSharedPreferences("loginvalue", MODE_WORLD_READABLE); String loginuser = sp.getString("username", null); String loginpass = sp.getString("password", null); user = username.getText().toString(); pass = password.getText().toString(); String passmd5 = MD5(pass); String encryptmd5 = encryptmd5(passmd5); System.out.println("username="+loginuser+"-------------password="+loginpass); System.out.println("user=="+user+"-------------encryptmd5=="+encryptmd5); if(!user.equals("")&&!pass.equals("")) { if( user.equals(loginuser)&& encryptmd5.equals(loginpass)) { Intent intent = new Intent(); intent.setClass(MD5Demo.this, Login.class); MD5Demo.this.startActivity(intent); finish(); }else { Toast.makeText(getApplicationContext(), "密码是错误的!", Toast.LENGTH_LONG).show(); } }else { Toast.makeText(getApplicationContext(), "密码不能为空!", Toast.LENGTH_LONG).show(); } } }); } //MD5加密,32位 public static String MD5(String str) { MessageDigest md5 = null; try { md5 = MessageDigest.getInstance("MD5"); }catch(Exception e) { e.printStackTrace(); return ""; } char[] charArray = str.toCharArray(); byte[] byteArray = new byte[charArray.length]; for(int i = 0; i < charArray.length; i++) { byteArray[i] = (byte)charArray[i]; } byte[] md5Bytes = md5.digest(byteArray); StringBuffer hexValue = new StringBuffer(); for( int i = 0; i < md5Bytes.length; i++) { int val = ((int)md5Bytes[i])&0xff; if(val < 16) { hexValue.append("0"); } hexValue.append(Integer.toHexString(val)); } return hexValue.toString(); } // 可逆的加密算法 public static String encryptmd5(String str) { char[] a = str.toCharArray(); for (int i = 0; i < a.length; i++) { a[i] = (char) (a[i] ^ 'l'); } String s = new String(a); return s; } }
程序很简单,下面是运行的效果:
大小: 9.2 KB
大小: 14.7 KB
大小: 24 KB
大小: 6.8 KB
查看图片附件
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