In this guide, we will walk you through the process of resolving the "Call to undefined function password_hash()" error in PHP. This error occurs when the PHP version in use is not compatible with the
password_hash() function. We'll discuss why this error occurs, how to check your PHP version, and how to upgrade your PHP version to solve this error. Additionally, we'll cover some frequently asked questions related to this topic.
Table of Contents
Understanding the Error
password_hash() function is used to create a new password hash using a strong one-way hashing algorithm. This function is available in PHP 5.5.0 and later versions. If you are using an earlier version of PHP, you will encounter the "Call to undefined function password_hash()" error. To resolve this error, you need to upgrade your PHP version to at least 5.5.0.
Checking Your PHP Version
Before upgrading your PHP version, you need to check the current version of PHP installed on your system. You can do this by creating a new PHP file and adding the following code:
<?php echo 'Current PHP version: ' . phpversion(); ?>
Save this file as
phpinfo.php and upload it to your web server. Then, open this file in your browser to see the current PHP version.
Alternatively, you can check the PHP version via the command line by running the following command:
Upgrading Your PHP Version
Once you've determined your current PHP version, follow the steps below to upgrade it:
Backup your website: Before making any changes, make sure to create a backup of your website files and database.
Upgrade PHP on your hosting server: If your website is hosted on a server, you'll need to upgrade PHP through your hosting provider. Most hosting providers offer an option to upgrade PHP in their control panels. If you're not sure how to do this, consult your hosting provider's documentation or contact their support team.
- Test your website: After upgrading your PHP version, thoroughly test your website to ensure everything is working as expected.
1. What is the
password_hash() function used for?
password_hash() function is used to securely hash passwords using a strong one-way hashing algorithm. This makes it more difficult for attackers to crack the hashed passwords if they gain access to your database.
2. What are some alternatives to
password_hash() if I cannot upgrade my PHP version?
If you cannot upgrade your PHP version, you can use the crypt() function as an alternative. However, it is strongly recommended to upgrade your PHP version to take advantage of the improved security features provided by the
3. How can I verify a password hashed with
You can use the
password_verify() function to verify a password against a hashed password. This function returns
true if the provided password matches the hash, and
4. What are the recommended hashing algorithms for
PHP 5.5.0 and later versions provide the
PASSWORD_BCRYPT constants for use with the
password_hash() function. It is recommended to use
PASSWORD_DEFAULT, as it automatically uses the most secure algorithm available in your PHP version.
5. Can I use the
password_hash() function with older PHP versions?
Yes, you can use the password_compat library, which provides a compatibility layer for older PHP versions (5.3.7 and later) to use the
password_hash() function. However, it is still recommended to upgrade your PHP version for the best security features.