Secret动态密码生成算法

import android.text.TextUtils;
import android.util.Log;

import java.math.BigInteger;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Locale;

/**
 * Created by ZengCS on 2018/1/19.
 * E-mail:zcs@sxw.cn
 * Add:成都市天府软件园E3-3F
 */
public class SxwDynamicPwdGenerator {
    private static final String TAG = "SxwDynamicPwdGenerator";
    private static final String PRIVATE_KEY = "cn.sxw.android.launcher";// 私钥
    public static final int REFRESH_DELAY = 60;// 60秒刷一次

    public static String getDynamicPwdString(String deviceId) {
        List<String> strings = generateDynamicPwd(deviceId);
        if (strings == null || strings.size() == 0) {
            return "";
        }
        StringBuilder sb = new StringBuilder();
        for (String pwd : strings) {
            sb.append(pwd);
        }
        return sb.toString();
    }

    public static List<String> generateDynamicPwd(String deviceId) {
        List<String> mItems = new ArrayList<>();
        String userSrc = MD5Util.getMd5(deviceId + "-" + getTime());
        String pwdSrc = MD5Util.getMd5(deviceId + "-" + getTime() + "-" + PRIVATE_KEY);
        Log.d(TAG, "generateDynamicPwd: userSrc = " + userSrc);
        Log.d(TAG, "generateDynamicPwd: pwdSrc = " + pwdSrc);
        if (TextUtils.isEmpty(pwdSrc)) {
            return null;
        }

        mItems.clear();
        for (int i = 0; i < 6; i++) {
            int start = i * 5;
            int end = 5 * (i + 1);
            if (i == 4) {
                end += 1;
            }
            if (i == 5) {
                start += 1;
                end += 2;
            }
            String tempPwd = pwdSrc.substring(start, end);
            //log("十六进制:" + tempPwd);
            BigInteger bigInteger = new BigInteger(tempPwd, 16);
            //log("十进制:" + bigInteger);
            String resultNumber = NumberUtil.bigIntegerToSingleNumber(bigInteger.toString());
            //log("resultNumber = " + resultNumber);
            mItems.add(resultNumber);
        }
        return mItems;
    }

    private static String getTime() {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmm", Locale.CHINA);
        String src = dateFormat.format(new Date());
        if (REFRESH_DELAY == 30) {
            int currSecond = getCurrSecond();
            if (currSecond < 30) {
                src += "00";
            } else {
                src += "30";
            }
        } else {
            src += "00";
        }
        return src;
    }

    public static int getCurrSecond() {
        Calendar calendar = Calendar.getInstance();
        return calendar.get(Calendar.SECOND);
    }
}

public class NumberUtil {
    public static String bigIntegerToSingleNumber(String bigInteger) {
        int result = 0;
        for (int j = 0; j < bigInteger.length(); j++) {
            String s = bigInteger.substring(j, j + 1);
            result += Integer.parseInt(s);
        }
        if (String.valueOf(result).length() > 1) {
            return bigIntegerToSingleNumber(String.valueOf(result));
        }
        return String.valueOf(result);
    }
}