How to use PHP technology to prevent malicious registration behavior

How to use PHP technology to prevent malicious registration behavior

Malicious registration behavior means that some criminals use malicious means to register accounts in batches, thereby spamming information, advertising push, Bad behavior such as phishing attacks. In response to this situation, we can prevent malicious registration behavior by using PHP technology. This article will introduce some common technical methods and attach corresponding PHP code examples.

1. Image verification code

Image verification code is one of the most common methods to prevent malicious registration behavior. By adding an image verification code to the registration page, requiring users to enter the characters or numbers in the image, you can effectively prevent bots from registering.

The following is a code example of a simple image verification code:

<?php
session_start();

$code = '';
$chars = 'abcdefghjkmnpqrstuvwxyz23456789';

for ($i = 0; $i < 4; $i++) {
    $code .= $chars[mt_rand(0, strlen($chars) - 1)];
}

$_SESSION['code'] = $code;

header('Content-Type: image/png');

$font =  './font.ttf';
$im = imagecreatetruecolor(100, 30);
$bgColor = imagecolorallocate($im, 255, 255, 255);
$textColor = imagecolorallocate($im, 0, 0, 0);

imagefilledrectangle($im, 0, 0, 100, 30, $bgColor);

imagettftext($im, 18, 0, 10, 22, $textColor, $font, $code);

imagepng($im);
imagedestroy($im);
?>

Save the above code as captcha.php, and then reference the file on the registration page. Display verification code image.

2. SMS verification code

In addition to the image verification code, you can also use SMS verification code for registration verification. When registering, users need to provide a mobile phone number and a verification code will be sent to the mobile phone number. Users need to enter the correct verification code to complete registration.

The following is a code example of a simple SMS verification code:

<?php
session_start();

$code = '';
$chars = '0123456789';

for ($i = 0; $i < 4; $i++) {
    $code .= $chars[mt_rand(0, strlen($chars) - 1)];
}

$_SESSION['code'] = $code;

// 调用短信接口，发送验证码到用户手机号码上
// ...

?>

After the user enters the mobile phone number on the registration page and clicks the Send Verification Code button, the above code can be called to send verification to the user's mobile phone code.

3. IP Restrictions

Malicious registration behaviors usually use multiple IP addresses for batch registration. By monitoring the user's IP address and setting a limit on the maximum number of registrations within a time period, malicious registration behaviors can be effectively curbed.

The following is a simple code example of IP restriction:

<?php
$ip = $_SERVER['REMOTE_ADDR'];

// 检查该IP地址在指定时间段内的注册次数
function checkIP($ip) {
    $expire = time() - 3600; // 限制在一小时内最多注册次数
    
    // 在数据库或其他存储中查询该IP地址的注册记录
    // ...
    
    // 如果在限制时间范围内注册次数超过指定次数，则返回 false
    // ...
    
    // 否则返回 true
    return true;
}

if (!checkIP($ip)) {
    die("您的IP地址注册次数过多，请稍后再试。");
}

// 允许用户进行注册
// ...
?>

The above code will check the number of registrations of the user's IP address within the specified time period. If the number of registrations exceeds the limit, the user will be prompted for a moment. Try again later.

In summary, by using technical means such as picture verification codes, SMS verification codes, and IP restrictions, we can effectively prevent malicious registration behaviors from occurring. Of course, specific protective measures need to be adjusted and improved based on the actual situation to improve registration security and user experience.

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