PHP 7 Password Storage Security Guide: How to Verify Passwords Using the Password_verify Function

PHP 7 Password Storage Security Guide: How to Use the Password_verify Function to Verify Passwords

Passwords are an important layer of protection for user accounts and sensitive information. When developing a website or application, correctly storing and validating user passwords is critical. Password security technology has continued to improve and evolve over time. PHP 7 introduces new password storage and verification functions to make password protection more secure and reliable.

This article will introduce how to use the password_verify function in PHP 7 to verify passwords. We'll discuss the concepts of password hashes and salts and provide some code examples to help you better understand and implement password storage security.

1. Password Hashing and Salting
   Prior to PHP 7, common password storage methods were to save passwords as clear text or use less secure hashing algorithms. This method poses serious security risks, because once the database is leaked, hackers can easily obtain user passwords.

To solve this problem, PHP 7 introduced the concepts of password hashes and salts. A password hash is a piece of code generated by converting the original password into a fixed-length string. With password hashing, the actual value of the password is not stored directly in the database, thus protecting the security of user passwords.

The salt is a randomly generated string used in conjunction with a user's password to increase the complexity of the password hash. It prevents hackers from cracking passwords using pre-computed password hashes like rainbow tables. Each user should have a unique salt value.

2. Use the password_verify function to verify passwords
   In PHP 7, we can use the password_verify function to verify user passwords. Here is a sample code that uses the password_verify function:

// 从用户输入中获取密码
$userInputPassword = $_POST['password'];

// 从数据库中获取哈希密码和盐
$storedHash = $row['password_hash'];
$salt = $row['salt'];

// 生成输入密码的哈希值
$inputHash = password_hash($userInputPassword . $salt, PASSWORD_DEFAULT);

// 验证密码
if (password_verify($inputHash, $storedHash)) {
    echo '密码验证成功';
} else {
    echo '密码验证失败';
}

3. Sample explanation
   This sample code works as follows:

• From user Get the password while typing.
• Get the stored hashed password and salt from the database.
• Use the password_hash function to generate the hash value of the input password. Note that we combine the password with a salt before hashing it.
• Use the password_verify function to verify that the hash value of the entered password matches the hashed password stored in the database.

4. Password storage security practices
   In addition to using the password_verify function, there are some other password storage security practices that need to be noted:

• Use Strong hashing algorithms: Use password hashing algorithms like bcrypt or Argon2 instead of vulnerable algorithms like MD5 or SHA.
• Generate a random salt value: Each user should have a unique salt value to increase the difficulty of cracking passwords.
• Password policy settings: Require users to choose strong passwords and force changes after password expiration.
• Prevent brute force attacks and exposure: Limit password retries and use HTTPS to protect password transmission.

Summary
PHP 7 provides a more secure and reliable method of password storage and verification. By using the password_verify function and properly implemented password storage security practices, we are able to protect user passwords from hackers. When developing a website or application, keep the importance of password security in mind and keep it updated and implement new password storage technologies.

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