PHP 7 Password Storage Security Guide: How to Use the Password_hash Function to Generate Password Hash

PHP 7 Password Storage Security Guide: How to use the password_hash function to generate password hashes

Password security has always been an important issue in Internet application development. To protect the security of user accounts, developers need to store users' passwords correctly and ensure that they are not accessed by unauthorized persons. In PHP 7 we have a very powerful function password_hash which provides a simple and secure way to generate password hashes. This article will show you how to use the password_hash function to generate a password hash, and give you some best practice example code.

What is password hashing?

Password hashing is a way of storing passwords by mathematically converting the original password into a string of seemingly random characters. This means that even if the password hash in the database is leaked, an attacker cannot easily crack the original password. When a user logs in, we can compare the password the user entered to the stored hash without storing the user's clear text password.

How to use password_hash function to generate password hash?

The password_hash function is very simple and easy to use. It accepts two parameters: the original password to be hashed and the specified hashing algorithm. Now, let's look at an example:

$rawPassword = "myPassword";
$options = ['cost' => 12];
$hashedPassword = password_hash($rawPassword, PASSWORD_DEFAULT, $options);

In the above example, we used the default value of the cryptographic algorithm and specified a "cost" option. The "cost" option indicates the number of iterations required to calculate the hash. The higher this value, the longer it takes to calculate the hash and the time it takes for an attacker to crack the password. Generally, setting "cost" to a value between 10-12 is a good choice.

How to verify the hash value?

Once the password hash is generated, we can use the password_verify function to verify that the password entered by the user when logging in is correct. Here is a simple example:

$rawPassword = "myPassword";
$hashedPassword = "<从数据库中获取的哈希值>";

if (password_verify($rawPassword, $hashedPassword)) {
    echo "密码正确";
} else {
    echo "密码错误";
}

In the above code, we compare the password entered by the user with the hash value stored in the database. If the passwords match, the password entered by the user is correct.

Best Practices

In addition to using the password_hash and password_verify functions, there are several other best practices that can help enhance the security of passwords:

1. Use HTTPS: Ensure that passwords are encrypted during transmission, which can be achieved by using HTTPS.
2. Don’t implement your own password hashing algorithm: whenever possible, use a secure algorithm that has been extensively tested and reviewed, such as that provided by the password_hash function.
3. Never store clear text passwords: Storing clear text passwords is not allowed even during development and testing phases.
4. Change passwords regularly: Users are advised to change their passwords regularly to prevent the long-term risk of password compromise.

Summary

In PHP 7, it is easy to generate a password hash using the password_hash function and verify the correctness of the password through the password_verify function. Properly storing and validating passwords is critical to the security of your application. By adopting the best practices described in this article, you can enhance the security of your user accounts while reducing the risk of password compromise.

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