Google Authenticator JAVA实例

代码来源：https://github.com/wstrange/GoogleAuth

验证代码：

 

package com.warner.java;

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;

/**
 * Java Server side class for Google Authenticator's TOTP generator
 * Thanks to Enrico's blog for the sample code:
 * @see http://thegreyblog.blogspot.com/2011/12/google-authenticator-using-it-in-your.html
 * @see http://code.google.com/p/google-authenticator
 * @see http://tools.ietf.org/id/draft-mraihi-totp-timebased-06.txt
 */
public class GoogleAuthenticator {
    
    // taken from Google pam docs - we probably don't need to mess with these
    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
    
    /**
     * 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.
     * @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 = "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);
    }
    
    /**
     * Check the code entered by the user to see if it is valid
     * @param secret The users secret.
     * @param code The code displayed on the users device
     * @param t The time in msec (System.currentTimeMillis() for example)
     * @return
     */
    public boolean check_code(String secret, long 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 (hash == 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;
    }
}

 测试代码：

 

 

package com.warner.test;

import org.junit.Test;
import com.warner.java.GoogleAuthenticator;

/*
 * Not really a unit test- but it shows usage
 */
public class GoogleAuthTest {
    
    @Test
    public void genSecretTest() {
        String secret = GoogleAuthenticator.generateSecretKey();
        String url = GoogleAuthenticator.getQRBarcodeURL("testuser", "testhost", secret);
        System.out.println("Please register " + url);
        System.out.println("Secret key is " + secret);
    }
    
    // Change this to the saved secret from the running the above test. 
    static String savedSecret = "F6EUJJMYK7GDC4KI";
    
    @Test
    public void authTest() {
        // enter the code shown on device. Edit this and run it fast before the code expires!
        long code = 349394;
        long t = System.currentTimeMillis();
        GoogleAuthenticator ga = new GoogleAuthenticator();
        ga.setWindowSize(5); //should give 5 * 30 seconds of grace...
        boolean r = ga.check_code(savedSecret, code, t);
        System.out.println("Check code = " + r);
    }
}

 

 

所需JAR包：

commons-codec-1.8.jar

junit-4.10.jar

 

测试方法：

1、执行测试代码中的“genSecretTest”方法，将生成一个URL和一个KEY（用户为testuser），URL打开是一张二维码图片。

2、在手机中下载“GOOGLE身份验证器”。

3、在身份验证器中配置账户，输入账户名（第一步中的用户testuser）、密钥（第一步生成的KEY），选择基于时间。

4、修改测试代码中的“savedSecret”属性，用身份验证器中显示的数字替换测试代码中方法authTest中的code，运行authTest方法即可。