How Can PHP 5.5's `password_hash` and `password_verify` Functions Secure Password Management?

Using PHP 5.5's Password Hashing Functions for Secure Password Management

Securing user passwords is crucial in modern web applications. PHP 5.5 introduced the password_hash and password_verify functions to enhance password security. Proper implementation of these functions ensures that passwords are stored securely and verified efficiently.

Password Hashing: Storing Passwords Safely

The password_hash function generates a secure hash of a given password using an encryption algorithm, typically bcrypt. This hash is stored in the database instead of the plain text password, making it difficult for attackers to retrieve sensitive information. To achieve optimal security, the function accepts a cost parameter that determines the computational effort required to generate the hash.

Incorrect: Storing Only the Salt

In the example provided, the code retrieves only the salt, which is insufficient for password verification. Both the hash and salt must be stored together in the database.

Correct: Storing Both Hash and Salt

The correct approach is to store both the hash and salt using the password_hash function:

$hashAndSalt = password_hash($password, PASSWORD_BCRYPT);
// Insert $hashAndSalt into database

Password Verification: Validating Credentials

To verify the user's password during login, the password_verify function is used. It compares the provided password with the stored hash and salt, returning true if they match and false if they do not.

// Fetch hash+salt from database
// and then to verify $password:
if (password_verify($password, $hashAndSalt)) {
   // Verified
}

By utilizing password_hash and password_verify, developers can implement secure password management in PHP applications. Remember to follow security best practices such as using mysqli for database interactions and preventing SQL injection vulnerabilities.

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