import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
import java.security.SecureRandom;
import java.util.Arrays;

public class Main {
    private static final int LOOPS = 1000;

    public static void main(String[] args) throws Exception {
        SecureRandom random = new SecureRandom();

        byte[] keyBytes = new byte[32];
        random.nextBytes(keyBytes);
        Key key = new SecretKeySpec(keyBytes, "AES");

        byte[] ivBytes = new byte[16];
        random.nextBytes(ivBytes);
        IvParameterSpec iv = new IvParameterSpec(ivBytes);

        Cipher encrypt = Cipher.getInstance("AES/CTR/NoPadding");
        Cipher decrypt = Cipher.getInstance("AES/CTR/NoPadding");

        while (true) {
            byte[][] unencryptedStuff = new byte[LOOPS][];
            byte[][] encryptedStuff = new byte[LOOPS][];

            encrypt.init(Cipher.ENCRYPT_MODE, key, iv);
            for (int i = 0; i < LOOPS; i++) {
                int size = (i % 15) + 1;

                byte[] unencrypted = new byte[size];
                random.nextBytes(unencrypted);
                unencryptedStuff[i] = unencrypted;

                byte[] encrypted = encrypt.update(unencrypted);
                encryptedStuff[i] = encrypted;
            }

            decrypt.init(Cipher.DECRYPT_MODE, key, iv);
            for (int i = 0; i < LOOPS; i++) {
                byte[] decrypted = decrypt.update(encryptedStuff[i]);
                byte[] original = unencryptedStuff[i];

                if (!Arrays.equals(original, decrypted)) {
                    throw new Exception("Array mismatch. " + Arrays.toString(original) + " " + Arrays.toString(decrypted));
                }
            }
        }
    }
}