PHP で AES256 を使用してファイルを安全に暗号化および復号化する方法

class AES256Encryption
{
    public const BLOCK_SIZE = 8;
    public const IV_LENGTH = 16;
    public const CIPHER = 'AES256';

    public static function generateIv(bool $allowLessSecure = false): string
    {
        // Logic to generate a secure initialization vector
    }

    protected static function getPaddedText(string $plainText): string
    {
        // Logic to pad the plaintext to a multiple of the block size
    }

    public static function encrypt(string $plainText, string $key, string $iv): string
    {
        // Logic to encrypt the plaintext using AES256
    }

    public static function decrypt(string $encryptedText, string $key, string $iv): string
    {
        // Logic to decrypt the ciphertext using AES256
    }
}

$text = 'Your plaintext here';
$key = 'Your encryption key';
$iv = AES256Encryption::generateIv();
$encryptedText = AES256Encryption::encrypt($text, $key, $iv);
$decryptedText = AES256Encryption::decrypt($encryptedText, $key, $iv);

// Print the results
echo "Original Text: $text" . PHP_EOL;
echo "Encrypted: $encryptedText" . PHP_EOL;
echo "Decrypted: $decryptedText" . PHP_EOL;