// Clear the master password after use
        Arrays.fill(masterPassword, '\0');
    }

    public byte[] encryptCredentials(char[] plaintext) throws GeneralSecurityException {
        checkNotDestroyed();

        if (plaintext == null) {
            return null;
        }

        // Convert char[] to byte[] for encryption
        byte[] plaintextBytes = charsToBytes(plaintext);

        try {