PHP Mobile Number Privacy Protection: How to Hide the Middle Four Digits

M66 2025-10-30

PHP Mobile Number Privacy Protection: Hide the Middle Four Digits

When handling sensitive information like users' mobile numbers in development, protecting privacy is essential. To avoid exposing users' numbers directly, we can process the phone numbers, such as hiding the middle four digits. This article shares methods to achieve this in PHP, along with example code.

Example Code for Hiding the Middle Four Digits

Here is a simple PHP function to hide the middle four digits of a mobile number:

function hidePhoneNumber($phoneNumber) {
    $maskedNumber = substr_replace($phoneNumber, '****', 3, 4);
    return $maskedNumber;
}

// Test example
$phoneNumber = '13812345678';
echo hidePhoneNumber($phoneNumber); // Output: 138****5678

Key Tips for Mobile Number Privacy Protection

The key to hiding the middle four digits is using the substr_replace() function, which replaces a specific part of the phone number with asterisks for privacy.
In practice, it is also recommended to validate the phone number format before processing to ensure the input is correct and avoid errors.

Complete Implementation Example

Here is a full PHP example, including phone number validation and middle four digits hiding:

function isValidPhoneNumber($phoneNumber) {
    // Simple validation: check if the phone number is 11 digits
    return preg_match('/^\d{11}$/', $phoneNumber);
}

function hidePhoneNumber($phoneNumber) {
    if(isValidPhoneNumber($phoneNumber)) {
        $maskedNumber = substr_replace($phoneNumber, '****', 3, 4);
        return $maskedNumber;
    } else {
        return 'Invalid phone number';
    }
}

// Test example
$phoneNumber = '13812345678';
echo hidePhoneNumber($phoneNumber); // Output: 138****5678

$invalidNumber = '123456'; // Invalid phone number
echo hidePhoneNumber($invalidNumber); // Output: Invalid phone number

This complete example demonstrates how to protect mobile number privacy by hiding the middle four digits. In real projects, you can further customize or extend the functionality to ensure user information security.

Conclusion

This article explains how to use PHP to protect mobile number privacy, including techniques to hide the middle four digits and full code examples. Protecting user privacy is crucial in development, and these methods help developers handle sensitive information securely while improving user experience.

substr_replace