What are potential pitfalls of relying on $_SESSION variables for data persistence in PHP?

Potential pitfalls of relying on $_SESSION variables for data persistence in PHP include security vulnerabilities such as session hijacking, data inconsistency if multiple tabs are used, and scalability issues as sessions are stored on the server. To mitigate these risks, consider using database storage for critical data and encrypting sensitive information stored in $_SESSION variables. 

// Example of encrypting sensitive information stored in $_SESSION variable
session_start();

// Set sensitive data in $_SESSION variable
$_SESSION['user_id'] = 12345;

// Encrypt sensitive data before storing in $_SESSION
$encrypted_data = openssl_encrypt($_SESSION['user_id'], 'AES-256-CBC', 'secret_key', 0, '16charIV');
$_SESSION['user_id'] = $encrypted_data;

// Decrypt sensitive data when needed
$decrypted_data = openssl_decrypt($_SESSION['user_id'], 'AES-256-CBC', 'secret_key', 0, '16charIV');
echo $decrypted_data;

Keywords

$_SESSION data persistence security session hijacking serialization

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