Java实现谷歌身份验证器

ゝ一世哀愁。 2023-07-05 13:12 67阅读 0赞

1.  生成一个随机秘钥

public static String generateSecretKey() throws NoSuchAlgorithmException { 
            SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
            sr.setSeed(Base64.decodeBase64("fooabrbalabala"));
            byte[] buffer = sr.generateSeed(10);
            Base32 codec = new Base32();
            byte[] bEncodedKey = codec.encode(buffer);
            return new String(bEncodedKey);
        }

1.  生成二维码

public static String getQRBarcode(String user, String secret, String issuer) { 
            String format = "otpauth://totp/%s?secret=%s&issuer=%s";
            return String.format(format, user, secret, issuer);
        }

1.  扫码添加  
    根据服务端生成的二维码字符串生成二维码图片，用户在`身份验真器`扫码添加。  
    e.g.

otpauth://totp/yimcarson?secret=VIABPOEXKBBMLZD2&issuer=CSDN

![身份验证器二维码][20210625204935129.png_pic_center]

![Google身份验证器截屏][Google]

1.  生成验证码  
    身份验证器每个30秒更新一次验证码，服务端校验时根据系统时间和密钥生成验证码。

public static int generateCode(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;
        }

@Test
        public void generateCode() throws InvalidKeyException, NoSuchAlgorithmException { 
            byte[] key = new Base32().decode("H3GKOORXVD76URAB");
            long t = (System.currentTimeMillis() / 1000L) / 30L;
            int code = GoogleAuthenticator.generateCode(key, t);
            System.out.println(code);
        }

1.  校验验证码  
    为了避免用户输入、网路等延时因素引起的校验问题，服务端通常会根据时间校验多个值。

/** * 最多可偏移的时间 * default 3 - max 17 */
        int window_size = 3;
    	public boolean checkCode(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 = generateCode(decodedKey, t + i);
                } catch (Exception e) { 
                    e.printStackTrace();
                    throw new RuntimeException(e.getMessage());
                }
                if (hash == code) { 
                    return true;
                }
            }
            return false;
        }

[20210625204935129.png_pic_center]: https://img-blog.csdnimg.cn/20210625204935129.png#pic_center
[Google]: https://img-blog.csdnimg.cn/20210625205617844.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpbWNhcnNvbg==,size_16,color_FFFFFF,t_70