PHP Data Masking: Real-World Privacy in 2026 Explained

#PHP Code

<?php
    if(isset($_POST['username']) && isset($_POST['phone'])){
        $username = $_POST['username'];
        $phone = $_POST['phone'];
        if(!empty($username) && !empty($phone)){
            $result = preg_replace('/.(?=.{4})/', "#", $phone);
            echo 'Username = ' .$username;
            echo '<br/>';
            echo 'Phone = ' .$result;
        }else{
            echo 'All fields are requied to fill.';
        }
    }
?>

#HTML Code

<form action="" method="post">
    <div class="form-group">
        <div class="form-control">
            <label for="">Username</label>
            <input type="text" name="username" id="">
        </div>
        <div class="form-control">
            <label for="">Phone No.</label>
            <input type="text" name="phone" id="">
        </div>
        <div class="form-control">
            <input type="submit" value="Submit">
        </div>
    </div>
</form>

#CSS Code

body{
    text-align: center;
}
form{
    position: relative;
    display: grid;
    grid-auto-flow: column;
    justify-items: center;
    
}
.form-group{
   width: 320px;
   padding: 20px;
   border: 1px solid #ccc;
   border-radius: 5px;
}
.form-control{
    padding: 20px;
}
input[type=submit]{
    cursor: pointer;
    padding: 5px 10px;
}