关于android:Android设备唯一性判断

package com.suning.mobile.epa; import java.security.MessageDigest;import java.security.NoSuchAlgorithmException; import android.content.Context;import android.os.Build;import android.provider.Settings.Secure;import android.telephony.TelephonyManager; public class DeviceFactoty {      // buildId    public String m_szDevIDShortMaker() {        String m_szDevIDShort = "35";         m_szDevIDShort += Build.BOARD.length() % 10 + Build.BRAND.length() % 10                + Build.CPU_ABI.length() % 10 + Build.DEVICE.length() % 10                + Build.DISPLAY.length() % 10 + Build.HOST.length() % 10                + Build.ID.length() % 10 + Build.MANUFACTURER.length() % 10                + Build.MODEL.length() % 10 + Build.PRODUCT.length() % 10                + Build.TAGS.length() % 10 + Build.TYPE.length() % 10                + Build.USER.length() % 10 + "";         return m_szDevIDShort;    }       public String currentDeviceMark(Context context) {        final TelephonyManager tm = (TelephonyManager) context                .getSystemService(Context.TELEPHONY_SERVICE);         final String tmDevice, tmSerial, androidId;        tmDevice = "" + tm.getDeviceId();        tmSerial = "" + tm.getSimSerialNumber();        androidId = ""                + android.provider.Settings.Secure.getString(EPApp.getApp()                        .getContentResolver(), Secure.ANDROID_ID);        String serial = "";        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.FROYO){            serial = Build.SERIAL;        }        String m_szLongID = tmDevice + tmSerial + androidId + serial                + m_szDevIDShortMaker();        MessageDigest m = null;        try {            m = MessageDigest.getInstance("MD5");        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();        }        m.update(m_szLongID.getBytes(), 0, m_szLongID.length());        // get md5 bytes        byte p_md5Data[] = m.digest();        // create a hex string        String m_szUniqueID = new String();        for (int i = 0; i < p_md5Data.length; i++) {            int b = (0xFF & p_md5Data[i]);            // if it is a single digit, make sure it have 0 in front (proper padding)            if (b <= 0xF)                m_szUniqueID += "0";            // add number to string            m_szUniqueID += Integer.toHexString(b);        } // hex string to uppercase        return m_szUniqueID = m_szUniqueID.toUpperCase();     }}