What are the best practices for encrypting data before writing it with fwrite in PHP?

When writing data to a file using fwrite in PHP, it is important to encrypt sensitive information to ensure its security. One way to achieve this is by using a strong encryption algorithm like AES along with a secure encryption key. This will help protect the data from unauthorized access and maintain its confidentiality.

// Encryption key - should be kept secure
$key = 'your_secret_key';

// Data to be encrypted
$data = 'sensitive information';

// Encrypt the data using AES encryption
$encryptedData = openssl_encrypt($data, 'AES-256-CBC', $key, 0, $key);

// Write the encrypted data to a file
$fp = fopen('encrypted_data.txt', 'w');
fwrite($fp, $encryptedData);
fclose($fp);