Google动态验证码

Posted 2020-12-01 echo777

Google动态验证码作用：可以动态的生成一个6位数的验证码，可以用于双重验证，增加网站的安全性。

条件：首先需要在手机上下载一个Google 验证器。（google authenticator app）

还需要在你的项目中引入一个Jar最主要的

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.13</version>
</dependency>

一个主要的方法

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

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class GoogleAuthenticatorUtil {
    // 生成的key长度( Generate secret key length)
    public static final int SECRET_SIZE = 10;

    public static final String SEED = "g8GjEvTbW5oVSV7avL47357438reyhreyuryetredLDVKs2m0QN7vxRs2im5MDaNCWGmcD2rvcZx";
    // Java实现随机数算法
    public static final String RANDOM_NUMBER_ALGORITHM = "SHA1PRNG";
    // 最多可偏移的时间
    int window_size = 3; // default 3 - max 17

    /**
     * set the windows size. This is an integer value representing the number of
     * 30 second windows we allow The bigger the window, the more tolerant of
     * clock skew we are.
     *
     * @param s
     *            window size - must be >=1 and <=17. Other values are ignored
     */
    public void setWindowSize(int s) {
        if (s >= 1 && s <= 17)
            window_size = s;
    }

    /**
     * Generate a random secret key. This must be saved by the server and
     * associated with the users account to verify the code displayed by Google
     * Authenticator. The user must register this secret on their device.
     * 生成一个随机秘钥
     *
     * @return secret key
     */
    public 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;
    }

    /**
     * Return a URL that generates and displays a QR barcode. The user scans
     * this bar code with the Google Authenticator application on their
     * smartphone to register the auth code. They can also manually enter the
     * secret if desired
     *
     * @param user
     *            user id (e.g. fflinstone)
     * @param host
     *            host or system that the code is for (e.g. myapp.com)
     * @param secret
     *            the secret that was previously generated for this user
     * @return the URL for the QR code to scan
     */
    public static String getQRBarcodeURL(String user, String host, String secret) {
        String format = "http://www.google.com/chart?chs=200x200&chld=M%%7C0&cht=qr&chl=otpauth://totp/%s@%s?secret=%s";
        return String.format(format, user, host, secret);
    }

    /**
     * 生成一个google身份验证器，识别的字符串，只需要把该方法返回值生成二维码扫描就可以了。
     *
     * @param user
     *            账号
     * @param secret
     *            密钥
     * @return
     */
    public static String getQRBarcode(String user, String secret) {
        String format = "otpauth://totp/%s?secret=%s";
        return String.format(format, user, secret);
    }

    /**
     * Check the code entered by the user to see if it is valid 验证code是否合法
     *
     * @param secret
     *            The users secret.
     * @param code
     *            The code displayed on the users device
     * @param timeMsec
     *            The time in msec (System.currentTimeMillis() for example)
     * @return
     */
    public boolean check_code(String secret, String code, long timeMsec) {
        Base32 codec = new Base32();
        byte[] decodedKey = codec.decode(secret);
        // convert unix msec time into a 30 second "window"
        // this is per the TOTP spec (see the RFC for details)
        long t = (timeMsec / 1000L) / 30L;
        // Window is used to check codes generated in the near past.
        // You can use this value to tune how far you‘re willing to go.
        for (int i = -window_size; i <= window_size; ++i) {
            long hash;
            try {
                hash = verify_code(decodedKey, t + i);
            } catch (Exception e) {
                // Yes, this is bad form - but
                // the exceptions thrown would be rare and a static
                // configuration problem
                e.printStackTrace();
                throw new RuntimeException(e.getMessage());
                // return false;
            }
            if (String.format ( "%06d",hash ).equals(code)) {
                return true;
            }
        }
        // The validation code is invalid.
        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;
        // We‘re using a long because Java hasn‘t got unsigned int.
        long truncatedHash = 0;
        for (int i = 0; i < 4; ++i) {
            truncatedHash <<= 8;
            // We are dealing with signed bytes:
            // we just keep the first byte.
            truncatedHash |= (hash[offset + i] & 0xFF);
        }
        truncatedHash &= 0x7FFFFFFF;
        truncatedHash %= 1000000;
        return (int) truncatedHash;
    }
}

做一下测试

 private static String secret = "MRHMHLZPFBZEZWQ3";

    @Test
    public void getSecret(){//首先跑这个类，成功后得到的secret要赋给上面的secret
        secret = GoogleAuthenticatorUtil.generateSecretKey();
//        String qrCode = GoogleAuthenticatorUtil.getQRBarcodeURL("haha","http://10.10.10.124:8092",secret);
        String qrCode = GoogleAuthenticatorUtil.getQRBarcode("haha",secret);
        System.out.println("secret "+secret + " qrCode " + qrCode );//qrcode这个我们可以最为二维码的值，我这个是在前端用qrcode.min.js生成的一个二维码（需要用户扫码用的），将值加进去就可以了。
    }
    @Test
    public void testValidCode(){
        String code = "105799";//这个值是你再Google APP中拿到的动态验证码
        long time = System.currentTimeMillis ();
        GoogleAuthenticatorUtil g = new GoogleAuthenticatorUtil();
        System.out.println("secret "+secret );
        boolean result = g.check_code (secret,code,time);
        System.out.println ( result );//true就是表示验证码成功，否则失败
    }

同时生成的二维码，我们除了用前端的qrcode.min.js我们还可以用java生成一个二维码图片显示在页面上
需要一些google的jar包

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;
/**width:宽，height:高。content就是我们也要设置的二维码的值，google验证器的格式是

"otpauth://totp/" + user+ "?secret=" + secret;

public class QRCodeUtil {

    public static void createQRCode(HttpServletResponse response, String content, int width, int height) throws IOException {
        if (!StringUtil.isNullOrEmpty(content)) {
            response.setDateHeader("Expires", 0);
            // Set standard HTTP/1.1 no-cache headers.
            response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
            // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
            response.addHeader("Cache-Control", "post-check=0, pre-check=0");
            // Set standard HTTP/1.0 no-cache header.
            response.setHeader("Pragma", "no-cache");
            // return a jpeg
            response.setContentType("image/png");
            ServletOutputStream out = response.getOutputStream();
            try {
                HashMap<EncodeHintType, Comparable> hints = new HashMap<>(3);
                hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
                hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
                hints.put(EncodeHintType.MARGIN, 2);

                QRCodeWriter writer = new QRCodeWriter();
                BitMatrix bitMatrix = writer.encode(content, BarcodeFormat.QR_CODE, width, height, hints);

                BufferedImage bufferedImage = MatrixToImageWriter.toBufferedImage(bitMatrix);
                ImageIO.write(bufferedImage, "png", out);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (out != null) {
                    out.flush();
                    out.close();
                }
            }
        }
    }
}
我们除了自己写类，也可以引入google验证器的jar

<dependency>
    <groupId>com.warrenstrange</groupId>
    <artifactId>googleauth</artifactId>
    <version>1.2.0</version>
</dependency>

GoogleAuthenticator gAuth = new GoogleAuthenticator();

String secret= gAuth.createCredentials().getKey();//得到secret

gAuth.authorize(key, code)//验证