Google Authenticator的Java示例 - HelloWorld开发者社区

Google身份验证器Google Authenticator是谷歌推出的基于时间的一次性密码(Time-based One-time Password，简称TOTP)，只需要在手机上安装该APP，就可以生成一个随着时间变化的一次性密码，用于帐户验证。

相对于手机短信两步验证(Two-step verification)，Google Authenticator两步验证有两大好处：一是避免无法接收验证短信的痛苦，尤其是用国内手机接收国外短信，你会发现经常收不到;二是Google Authenticator不用联网也可用，手机欠费停机不影响。

国内外各大网站和应用都基本上支持Google Authenticator两步验证了。这篇文章就简单说明一下，如何在自己的网站上集成Google身份验证器

一、准备工作

需要jar包：commons-codec-1.8。

二、Java类

package controller;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base32;
import org.apache.commons.codec.binary.Base64;

public class GoogleAuthenticatorSample {

    public static final int SECRET_SIZE = 10;

    public static final String SEED = "g8GjEvTbW5oVSV7avLBdwIHqGlUYNzKFI7izOF8GwLDVKs2m0QN7vxRs2im5MDaNCWGmcD2rvcZx";

    public static final String RANDOM_NUMBER_ALGORITHM = "SHA1PRNG";

    int window_size = 3; // default 3 - max 17 (from google docs)最多可偏移的时间

    public void setWindowSize(int s) {
        if (s >= 1 && s <= 17)
            window_size = s;
    }

    /**
     * 验证身份验证码是否正确
     * 
     * @param codes
     *            输入的身份验证码
     * @param savedSecret
     *            密钥
     * @return
     */
    public static Boolean authcode(String codes, String savedSecret) {
        long code = 0;
        try {
            code = Long.parseLong(codes);
        } catch (Exception e) {
            e.printStackTrace();
        }
        long t = System.currentTimeMillis();
        GoogleAuthenticatorSample ga = new GoogleAuthenticatorSample();
        ga.setWindowSize(3); // should give 5 * 30 seconds of grace...
        boolean r = ga.check_code(savedSecret, code, t);
        return r;
    }

    /**
     * 获取密钥
     * 
     * @param user
     *            用户
     * @param host
     *            域
     * @return 密钥
     */
    public static String genSecret(String user, String host) {
        String secret = GoogleAuthenticatorSample.generateSecretKey();
        GoogleAuthenticatorSample.getQRBarcodeURL(user, host, secret);
        return secret;
    }

    private static String generateSecretKey() {
        SecureRandom sr = null;
        try {
            sr = SecureRandom.getInstance(RANDOM_NUMBER_ALGORITHM);
            sr.setSeed(Base64.decodeBase64(SEED));
            byte[] buffer = sr.generateSeed(SECRET_SIZE);
            Base32 codec = new Base32();
            byte[] bEncodedKey = codec.encode(buffer);
            String encodedKey = new String(bEncodedKey);
            return encodedKey;
        } catch (NoSuchAlgorithmException e) {
            // should never occur... configuration error
        }
        return null;
    }

    /**
     * 获取二维码图片URL
     * 
     * @param user
     *            用户
     * @param host
     *            域
     * @param secret
     *            密钥
     * @return 二维码URL
     */
    public static String getQRBarcodeURL(String user, String host, String secret) {
        String format = "https://www.google.com/chart?chs=200x200&chld=M%%7C0&cht=qr&chl=otpauth://totp/%s@%s%%3Fsecret%%3D%s";
        return String.format(format, user, host, secret);
    }

    private boolean check_code(String secret, long code, long timeMsec) {
        Base32 codec = new Base32();
        byte[] decodedKey = codec.decode(secret);
        long t = (timeMsec / 1000L) / 30L;
        for (int i = -window_size; i <= window_size; ++i) {
            long hash;
            try {
                hash = verify_code(decodedKey, t + i);
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e.getMessage());
            }
            if (hash == code) {
                return true;
            }
        }
        return false;
    }

    private static int verify_code(byte[] key, long t)
            throws NoSuchAlgorithmException, InvalidKeyException {
        byte[] data = new byte[8];
        long value = t;
        for (int i = 8; i-- > 0; value >>>= 8) {
            data[i] = (byte) value;
        }
        SecretKeySpec signKey = new SecretKeySpec(key, "HmacSHA1");
        Mac mac = Mac.getInstance("HmacSHA1");
        mac.init(signKey);
        byte[] hash = mac.doFinal(data);
        int offset = hash[20 - 1] & 0xF;
        long truncatedHash = 0;
        for (int i = 0; i < 4; ++i) {
            truncatedHash <<= 8;
            truncatedHash |= (hash[offset + i] & 0xFF);
        }
        truncatedHash &= 0x7FFFFFFF;
        truncatedHash %= 1000000;
        return (int) truncatedHash;
    }

    public static void main(String[] args) {
        /*
         * 注意：先运行前两步，获取密钥和二维码url。 然后只运行第三步，填写需要验证的验证码，和第一步生成的密钥
         */
        String user = "testUser";
        String host = "testHost";
        // 第一步：获取密钥
        String secret = genSecret(user, host);
        System.out.println("secret:" + secret);
        // 第二步：根据密钥获取二维码图片url（可忽略）
        String url = getQRBarcodeURL(user, host, secret);
        System.out.println("url:" + url);
        // 第三步：验证（第一个参数是需要验证的验证码，第二个参数是第一步生成的secret运行）
        boolean result = authcode("271239", "OHXU6PLMZMDJIDY6");
        System.out.println("result:" + result);
    }
}

Google Authenticator的Java示例