How to generate OTP one-time password with PHP

Nowadays, OTP (One Time Password) is mandatory in almost all services. Developers can generate OTPs in many ways, but the challenge is not predictive as anyone can predict OTPs and can leverage the service.

Some popular OTP formats are:

4 or 6 digit OTP.

4 or 6 letters (lowercase/uppercase) OTP.

4 or 6 digit alphanumeric OTP.

Example of n-digit OTP:

输入: n = 4
输出: 8723

输入: n = 8
输出: 23914072

Note: The output of the program will vary each time it is executed.

One of the best ways to generate OTP is to use a random function. But using random functions directly can be dangerous.

So, the example given below is a way to generate an n-digit OTP using a random function and some algorithms.

PHP program code examples are as follows:

<?php 
  
//创建生成OTP的函数 
function generateNumericOTP($n) { 
      
    // 以生成器字符串为例，它由以下内容组成
    //全部是数字
    $generator = "1357902468"; 
  
    //迭代n次，选择一个字符
    //从生成器并将其附加到$result中
    //登录从生成器生成随机字符
    // 生成一个随机数
    // 取与发电机长度相同的模量(如i)
    // 将字符从生成器追加到结果的(i)位置  
    $result = ""; 
  
    for ($i = 1; $i <= $n; $i++) { 
        $result .= substr($generator, (rand()%(strlen($generator))), 1); 
    } 
  
    // 返回结果
    return $result; 
} 

$n = 6; 
print_r(generateNumericOTP($n)); 
  
?>

Random output:

561862

This article is about the method of generating OTP (one-time password) in PHP. I hope it will help those who need it. Friends help!

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