Can you recommend or advise against a specific encryption method for PHP file encryption, considering performance and security?

When encrypting PHP files, it's important to choose a method that balances both performance and security. One recommended encryption method is using OpenSSL functions in PHP, which provides a good balance between security and performance. It offers strong encryption algorithms and is built into PHP, making it easy to implement.

```php
// Encrypt a PHP file using OpenSSL
$plaintext = file_get_contents('file_to_encrypt.php');
$key = 'your_secret_key';
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('aes-256-cbc'));
$ciphertext = openssl_encrypt($plaintext, 'aes-256-cbc', $key, 0, $iv);
file_put_contents('encrypted_file.php', $ciphertext);
```

Remember to securely store and manage your encryption key to ensure the security of your encrypted PHP files.