How can unique identifiers be used in PHP to securely generate and send password reset links to users who have forgotten their passwords?

To securely generate and send password reset links to users who have forgotten their passwords, unique identifiers can be used in PHP. These unique identifiers can be generated using functions like uniqid() or random_bytes() to create a token that is unique to each password reset request. This token can then be stored in a database along with the user's email address and expiration time. When the user clicks on the password reset link containing the token, the PHP script can verify the token against the database to ensure its validity before allowing the user to reset their password.

// Generate a unique identifier for the password reset token
$token = bin2hex(random_bytes(16));

// Store the token, user's email, and expiration time in a database table
// For example, using PDO to interact with the database
$stmt = $pdo->prepare("INSERT INTO password_resets (email, token, expires_at) VALUES (?, ?, ?)");
$stmt->execute([$email, $token, date('Y-m-d H:i:s', strtotime('+1 hour'))]);

// Send the password reset link to the user's email
$reset_link = "https://example.com/reset_password.php?token=$token";
$message = "Click on the following link to reset your password: $reset_link";
mail($email, "Password Reset Link", $message);