Validate bitcoin wallet passphrase

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

public class PasswordChecker {

    public static void main(String[] args) {
        String hash = "$bitcoin$64$0839e385bbc0e714376eb9919713b754a69175e79de9641441e495832f46f8eb$16$53ed1412a321a660$199514$2$00$2$00";
        String password = "your_supposed_passphrase";
        System.out.println(new PasswordChecker().check(password, hash));
    }

    public boolean check(String passphrase, String walletHash) {

        String withoutPrefix = walletHash.replaceFirst("^\\$bitcoin\\$", "");
        String[] split = withoutPrefix.split("\\$");

        String temp = bytesToHex(passphrase.getBytes()) + split[3];
        byte[] passToHash = hexStringToByteArray(temp);

        int iterCount = Integer.parseInt(split[4]);
        for (int i = 0; i < iterCount; ++i) {
            passToHash = calculateSha512(passToHash);
        }

        byte[] key = Arrays.copyOfRange(passToHash, 0, 32);
        byte[] iv = Arrays.copyOfRange(passToHash, 32, 48);

        try {
            decrypt(hexStringToByteArray(split[1]), key, iv);
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    private byte[] calculateSha512(byte[] data) {
        try {
            MessageDigest md = MessageDigest.getInstance("SHA-512");
            md.update(data);
            return md.digest();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    private void decrypt(byte[] encrypted, byte[] key, byte[] iv) throws Exception {
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
        SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
        cipher.doFinal(encrypted);
    }

    private static byte[] hexStringToByteArray(String s) {
        int len = s.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                    + Character.digit(s.charAt(i+1), 16));
        }
        return data;
    }

    private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
    private static String bytesToHex(byte[] bytes) {
        char[] hexChars = new char[bytes.length * 2];
        for (int j = 0; j < bytes.length; j++) {
            int v = bytes[j] & 0xFF;
            hexChars[j * 2] = HEX_ARRAY[v >>> 4];
            hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
        }
        return new String(hexChars);
    }
}