import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class LicenseManager {

    private static final String SECRET_KEY = "YourSecretKey"; // ½ÃÅ©¸´ Å°

    public static String generateLicenseKey(String computerName) {
        try {
            MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
            byte[] inputBytes = (computerName + SECRET_KEY).getBytes(StandardCharsets.UTF_8);
            byte[] hashBytes = sha1.digest(inputBytes);
            StringBuilder hexString = new StringBuilder();
            for (byte hashByte : hashBytes) {
                String hex = Integer.toHexString(0xff & hashByte);
                if (hex.length() == 1) {
                    hexString.append('0');
                }
                hexString.append(hex);
            }
            return hexString.toString();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }

    public static boolean validateLicenseKey(String computerName, String licenseKey) {
        return licenseKey.equals(generateLicenseKey(computerName));
    }

    public static void main(String[] args) {
        String computerName = System.getenv("COMPUTERNAME"); // ÄÄÇ»ÅÍ À̸§ °¡Á®¿À±â
        String licenseKey = generateLicenseKey(computerName);

        System.out.println("Generated license key for " + computerName + ": " + licenseKey);

        // Validate the license key
        boolean isValid = validateLicenseKey(computerName, licenseKey);
        System.out.println("License key is valid: " + isValid);
    }
}