If you have been mining Monero on your Threadripper, then using that cryptocurrency for buying hookers and blow, you might want to be aware those some of those older Monero transactions are not as private as you might think. All of which means Monero may continue to leak small amounts of information that could be used to point to likely spenders—even if not providing a smoking gun. Even so, the researchers warn that small information leaks can build up over time, and can be combined with other data sources to provide that more concrete evidence. Perhaps more disturbingly for Monero users who spent coins before its privacy improvements, indelible fingerprints could lead to their front door. And that points to a more fundamental problem for cryptocurrencies offering privacy: Any security flaw discovered in the future might apply retroactively, allowing observers to dig up old skeletons buried in the currency's blockchain.