public class SimpleOTPGenerator {


    protected SimpleOTPGenerator() {
    }

    public static String random(int size) {

        StringBuilder generatedToken = new StringBuilder();
        try {
            SecureRandom number = SecureRandom.getInstance("SHA1PRNG");
            // Generate 20 integers 0..20
            for (int i = 0; i < size; i++) {
                generatedToken.append(number.nextInt(9));
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return generatedToken.toString();
    }
}

Answer 4

protected void onCreate(Bundle savedInstanceState)
 {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Random otp  =new Random();

        StringBuilder builder=new StringBuilder();
        for(int count=0; count<=10;count++) {
            builder.append(otp.nextInt(10));
        }
        Log.d("Number", " " + builder.toString());

        TextView txt = (TextView) findViewById(R.id.txt);

        txt.setText(builder.toString());
   }

Answer 5

public static void main(String []args){
            java.util.Random r=new java.util.Random();
            int otp = r.nextInt(1000000); // no. of zeros depends on the OTP digit
            System.out.println(otp);
}

Answer 6

First of all OTP stands for one time password it is used for the authentication and 
verification this is code is for java implemented in netbeans IDE
 You have to register on the msg91.com for the api genration and that gives free 250 
 msgs.
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Random;
import javax.swing.JOptionPane;
 public class SMS {
String num,otp;
SMS(String mob)
{
    num=mob;

}
 static String otpGenerator() 
{ 
    String numbers = "0123456789"; 
    String x="";
    Random rndm_method = new Random(); 
    char[] otp = new char[4]; 
    for (int i = 0; i <4; i++) 
    { 
        otp[i]=numbers.charAt(rndm_method.nextInt(numbers.length())); 
        x=x+otp[i];
    } 

    return x; 
}//this is the function for the random number generator for otp
 public void sms(String otp)
{
        try {

        String apiKey = "api key on msg91.com";
        String message = otp;
        String sender = "TESTIN";
        String numbers = num;
                    String a="http://api.msg91.com/api/sendhttp.php? 
          country=91&sender="+ sender +"&route=4&mobiles=" + numbers +"&authkey=api 
           key on msg91.com&message="+message+" ";
                    //System.out.println(a);
                    // Send data
        HttpURLConnection conn = (HttpURLConnection) new URL(a).openConnection();
        String data = apiKey + numbers + message + sender;
        conn.setDoOutput(true);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Length", Integer.toString(data.length()));
        conn.getOutputStream().write(data.getBytes("UTF-8"));
        final BufferedReader rd = new BufferedReader(new 
         InputStreamReader(conn.getInputStream()));
        final StringBuffer stringBuffer = new StringBuffer();
        String line;
        while ((line = rd.readLine()) != null) {
            //stringBuffer.append(line);
                        //JOptionPane.showMessageDialog(null, "message"+line);
                        System.out.println("OTP SENT !");
        }
        rd.close();

        //return stringBuffer.toString();
    } catch (Exception e) {
                JOptionPane.showMessageDialog(null,e);

    }

}
//now you have to call this function and send your number as the parameter
 public Start() {
    this.setUndecorated(true);

    initComponents();

    jPasswordField1.setBackground(new Color(0, 0, 0, 0));

    jPasswordField1.setOpaque(false);  
    //jPasswordField1.setBorder(null); 
    this.setBounds(300, 200, 707, 390);
    SMS otp=new SMS("your number");
    x=otp.otpGenerator();
    otp.sms(x); 
    }

Answer 7

最简单的方法是将DecimalFormat与Random类一起使用。

String otp= new DecimalFormat("000000").format(new Random().nextInt(999999));
System.out.println(otp);

样本输出

Answer 8

Java 8在SplittableRandom软件包中引入了java.util。您可以使用它的nextInt(int origin, int bound)获取指定范围之间的随机数。

StringBuilder generatedOTP = new StringBuilder();
SplittableRandom splittableRandom = new SplittableRandom();

for (int i = 0; i < lengthOfOTP; i++) {

    int randomNumber = splittableRandom.nextInt(0, 9);
    generatedOTP.append(randomNumber);
}
return generatedOTP.toString();

但是我建议使用SecureRandom类。它提供了一个密码学强随机数，并且在软件包java.security中可用。

StringBuilder generatedOTP = new StringBuilder();
SecureRandom secureRandom = new SecureRandom();

try {

    secureRandom = SecureRandom.getInstance(secureRandom.getAlgorithm());

    for (int i = 0; i < lengthOfOTP; i++) {
        generatedOTP.append(secureRandom.nextInt(9));
    }
} catch (NoSuchAlgorithmException e) {
    e.printStackTrace();
}

return generatedOTP.toString();

您可能会从Java 8- OTP Generator获得更多信息

Answer 9

如其他答案所述，如何生成 TOTP (RFC 6238) 和 HOTP (RFC 4226) 代码的规则在 RFC 中定义。但是，如果您不想手动实现它们。你总是可以使用图书馆。

例如，我创建了一个用于创建一次性密码的库：OTP-Java

或者，如果您更喜欢自己实现代码，也可以查看代码的生成方式。

Answer 10

import java.util.*;

public class OTP2 {
  static char[] OTP(int len) {
    System.out.println("Generating OTP using random ()");
    System.out.print("Your OTP is:");

    // Using numeric values
    String numbers = "0123456789";

    // Using random method 
    Random rndm_method = new Random();
    char[] otp = new char[len];
    for(int i=0; i<len;i++) {
      // use of charAt() method : to get character value
      // use of nextInt() as it is scanning the value as int 
      otp[i] = numbers.charAt(rndm_method.nextInt(numbers.length()));
    }
    return otp;
  }

  public static void main(String args[]) {
    int length = 6;
    System.out.println(OTP(length));
  }
}

Answer 11

public class OTP 
{ 
public const int SECRET_LENGTH = 20; 
private const string 
MSG_SECRETLENGTH = "Secret must be at least 20 bytes", 
MSG_COUNTER_MINVALUE = "Counter min value is 1"; 

public OTP() 
{ 
} 

private static int[] dd = new int[10] { 0, 2, 4, 6, 8, 1, 3, 5, 7, 9 }; 

private byte[] secretKey = new byte[SECRET_LENGTH] 
{ 
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 
0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43 
}; 

private ulong counter = 0x0000000000000001; 

private static int checksum(int Code_Digits) 
{ 
int d1 = (Code_Digits/1000000) % 10; 
int d2 = (Code_Digits/100000) % 10; 
int d3 = (Code_Digits/10000) % 10; 
int d4 = (Code_Digits/1000) % 10; 
int d5 = (Code_Digits/100) % 10; 
int d6 = (Code_Digits/10) % 10; 
int d7 = Code_Digits % 10; 
return (10 - ((dd[d1]+d2+dd[d3]+d4+dd[d5]+d6+dd[d7]) % 10) ) % 10; 
} 

/// <summary> 
/// Formats the OTP. This is the OTP algorithm. 
/// </summary> 
/// <param name="hmac">HMAC value</param> 
/// <returns>8 digits OTP</returns> 
private static string FormatOTP(byte[] hmac) 
{ 
int offset = hmac[19] & 0xf ; 
int bin_code = (hmac[offset] & 0x7f) << 24 
| (hmac[offset+1] & 0xff) << 16 
| (hmac[offset+2] & 0xff) << 8 
| (hmac[offset+3] & 0xff) ; 
int Code_Digits = bin_code % 10000000; 
int csum = checksum(Code_Digits); 
int OTP = Code_Digits * 10 + csum; 

return string.Format("{0:d08}", OTP); 
} 

public byte[] CounterArray 
{ 
get 
{ 
return BitConverter.GetBytes(counter); 
} 

set 
{ 
counter = BitConverter.ToUInt64(value, 0); 
} 
} 

/// <summary> 
/// Sets the OTP secret 
/// </summary> 
public byte[] Secret 
{ 
set 
{ 
if (value.Length < SECRET_LENGTH) 
{ 
throw new Exception(MSG_SECRETLENGTH); 
} 

secretKey = value; 
} 
} 

/// <summary> 
/// Gets the current OTP value 
/// </summary> 
/// <returns>8 digits OTP</returns> 
public string GetCurrentOTP() 
{ 
HmacSha1 hmacSha1 = new HmacSha1(); 

hmacSha1.Init(secretKey); 
hmacSha1.Update(CounterArray); 

byte[] hmac_result = hmacSha1.Final(); 

return FormatOTP(hmac_result); 
} 

/// <summary> 
/// Gets the next OTP value 
/// </summary> 
/// <returns>8 digits OTP</returns> 
public string GetNextOTP()  
{ 
// increment the counter 
++counter; 

return GetCurrentOTP(); 
} 

/// <summary> 
/// Gets/sets the counter value 
/// </summary> 
public ulong Counter 
{ 
get 
{ 
return counter; 
} 

set 
{ 
counter = value; 
} 
} 
}

如何生成6位数的OTP号码

11 个答案: