checkNotClosed();

        byte[] key = new byte[length];
        secureRandom.nextBytes(key);
        return key;
    }

    /**
     * Clear all stored keys
     */
    public void clearAllKeys() {
        checkNotClosed();

        log.info("Clearing all stored keys");

        // Wipe all raw keys
        for (Map.Entry<String, byte[]> entry : rawKeys.entrySet()) {