Android 对用户名密码进行加密操作存储在本地

大家都知道当下大多数app都都有保存用户名密码的操作，仅仅将数据保存到SharedPreferences里面谁都能做的到，但是没有经过处理的数据直接以明文的形式存储，那么很容易就被坏人盗取，那么问题来了，如何对数据进行加密操作呢？
这就要用到加密算法，加密有对称加密，非对称加密。较为常用的有DES,3DES,PBE,AES等
下面我们所讲的就是其中的3DES
3DES加密算法属于对称加密，即加密和解密所用的密钥是同一个key
在进行3DES加密算法时要对加密算法最基础的Base64有一定的了解，因为Base64算法能对数据进行无损的编码
key是Java虚拟机创建的临时对象，程序结束时会自动回收，因为加解密所用的key必须是一个key，所以我们需要使用ObjectOutputStream对key进行保存
理清楚步骤：
1.得到加解密所使用key
2.对数据进行加密
3.对key进行保存
4.对加密后的数据进行保存
5.对数据进行读取
6.对key进行读取
7.解密，得到解密后的正确数据

话不多说直接上代码

package wkk.demo4;import android.content.Context;import android.content.SharedPreferences;import android.os.Environment;import android.text.TextUtils;import android.util.Base64;import android.util.Log;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESedeKeySpec;/** * Created by wkk on 2016/5/11. */public class PasswordHelp {    /**     * 保存账号密码     * @param context     * @param number     * @param password     * @param isRemember 是否记住密码     */    public static void savePassword(Context context, String number, String password, boolean isRemember) {        //对数据进行加密        //得到key        SecretKey key = PasswordHelp.readKey(PasswordHelp.getPath("a.a"));        if (key == null) {            key = get3DESKey();            //保存key            PasswordHelp.saveKey(key, PasswordHelp.getPath("a.a"));        }        //对得到number和password进行加密        byte[] numberByte = encrypt3DES(number, key);        byte[] passwordByte = encrypt3DES(password, key);        number = Base64.encodeToString(numberByte, Base64.DEFAULT);        password = Base64.encodeToString(passwordByte, Base64.DEFAULT);        SharedPreferences sharedPreferences = context.getSharedPreferences("user", Context.MODE_PRIVATE);        SharedPreferences.Editor editor = sharedPreferences.edit();        editor.putString("number", number);        editor.putString("password", password);        editor.putBoolean("isRemember", isRemember);        editor.commit();    }    //读取账号密码    public static String[] readPassword(Context context) {        SharedPreferences sharedPreferences = context.getSharedPreferences("user", Context.MODE_PRIVATE);        String str[] = new String[]{sharedPreferences.getString("number", ""), sharedPreferences.getString("password", ""), String.valueOf(sharedPreferences.getBoolean("isRemember", false))};        str[0] = d(str[0]);        str[1] = d(str[1]);        return str;    }    private static String d(String str) {        if (!TextUtils.isEmpty(str)) {            //对数据进行解密            SecretKey key = readKey(PasswordHelp.getPath("a.a"));            if (key != null) {                str = decoder3DES(Base64.decode(str.getBytes(), Base64.DEFAULT), key);            }        }        return str;    }    //保存key    public static boolean saveKey(SecretKey key, String path) {        try {            FileOutputStream fileOutputStream1 = new FileOutputStream(path);            ObjectOutputStream objectOutputStream = new ObjectOutputStream(                    fileOutputStream1);            objectOutputStream.writeObject(key);            objectOutputStream.flush();            objectOutputStream.close();            return true;        } catch (Exception e) {            Log.d("测试", e.toString());        }        return false;    }    //读取key    public static SecretKey readKey(String path) {        SecretKey key = null;        try {            ObjectInputStream objectInputStream = new ObjectInputStream(                    new FileInputStream(path));            key = (SecretKey) objectInputStream.readObject();            objectInputStream.close();        } catch (Exception e) {            Log.d("测试:读取key:", e.toString());        }        return key;    }    //获取路径    public static String getPath(String FileName) {        if (TextUtils.isEmpty(FileName)) {            return null;        }        File file = new File(Environment.getExternalStorageDirectory().getPath() + "/yhcm");        if (!file.exists() || !file.isDirectory()) {            file.mkdirs();        }        File file1 = new File(file, FileName);        if (!file1.exists() || !file1.isFile()) {            try {                file1.createNewFile();            } catch (IOException e) {                Log.d("测试:文件创建失败：", e.toString());                return null;            }        }        return file1.getPath();    }    /**     * 数据加解密3DES所需要的Key     */    public static SecretKey get3DESKey() {        try {            // 生成key            KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");            keyGenerator.init(168);// can 168 or 112/new SecureRandom()            SecretKey secretKey = keyGenerator.generateKey();            byte[] bytesKey = secretKey.getEncoded();            // 转化key            DESedeKeySpec deSedeKeySpec = new DESedeKeySpec(bytesKey);            SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");            SecretKey generateSecret = factory.generateSecret(deSedeKeySpec);            return generateSecret;        } catch (Exception e) {            e.printStackTrace();            Log.d("测试", e.toString());        }        return null;    }    /**     * 数据加密3DES     */    private static byte[] encrypt3DES(String str, SecretKey generateSecret) {        try {            // 加密            Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");            cipher.init(Cipher.ENCRYPT_MODE, generateSecret);            byte[] result = cipher.doFinal(str.getBytes("utf-8"));            return result;        } catch (Exception e) {            System.out.println("加密出错：" + e.getMessage());        }        return null;    }    /**     * 数据解密3DES     */    private static String decoder3DES(byte[] str, SecretKey generateSecret) {        try {            // 加密            Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");            cipher.init(Cipher.DECRYPT_MODE, generateSecret);            System.out.println(2);            byte[] result = cipher.doFinal(str);            System.out.println(3);            return new String(result, "utf-8");        } catch (Exception e) {            System.out.println("解密出错:" + e.getMessage());        }        return null;    }}

这个是我写的帮助类，可以调用savePassword和readPassword两个方法直接使用，当然建议修改下key文件存储的位置
上面的一些功能也可以用在其他的很多地方，需要自己去灵活应用