Libsodium はどのように PHP の AES 暗号化と復号化のセキュリティを強化できますか?

// Safe encryption function
function safeEncrypt($message, $key) {
    $nonce = sodium_randombytes_buf(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
    return base64_encode($nonce . sodium_crypto_secretbox($message, $nonce, $key));
}

// Safe decryption function
function safeDecrypt($encrypted, $key) {
    $decoded = base64_decode($encrypted);
    $nonce = substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
    $ciphertext = substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
    return sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
}

// Get a random key
$key = sodium_randombytes_buf(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
// Your message to encrypt
$message = 'Encrypting this message using Libsodium';

// Encrypt and decrypt
$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);

// Output results
var_dump($ciphertext); // Encrypted message
var_dump($plaintext); // Decrypted message