A future of personal and financial privacy might be closer and more realistic than you think.

The other day, I went to buy dog food at my local pet shop. I bought a large bag of dog food and some treats for my dog that claimed to be able to make her breath smell better. Toothbrush-shaped treats. I paid with my Chase Visa card and walked out of the store. A few minutes later, I happened to check Twitter and saw an advertisement pop up — for toothbrush-shaped dog treats. I thought: this was not an online purchase. I used nothing but my credit card. How did this happen?

The advertising was too specific to have been pulled from the geolocation of my phone, even though my iPhone was in my pocket and certainly knew that I was more or less at the location of a pet food store. If that was the case, then I could have been offered an advertisement for cat food, or normal dog food, or bird food, or any of the other hundreds of items on sale. But it was the toothbrush-shaped dog treats.

The offending tweet

Most likely, I was targeted with this advertising because one of the trusted third parties involved in my payment to the pet store knew not just that I bought something there — but that I made a very specific purchase for toothbrush-shaped dog treats.

My data was sold into the personal information markets, without asking me, and without an opportunity for me to share in the profit. Thanks to big data analysis, within minutes my purchase was locked into the growing system of surveillance capitalism.

So who leaked my data? Was the guilty party Pet Food Express? Chase? Visa? Most likely Chase — given that they have confirmed that they share information about consumer purchases with third parties — but we don’t need to know the exact answer to see the inherent and striking problem:

Today’s digital payments are privacy holes.

As a civil liberties advocate, I’ve racked my brain to figure out what solutions might exist to help us address this problem.

We know that financial surveillance won’t stop mutating at relatively harmless advertisements for us to buy more dog treats. We’ve seen what happens in dictatorships like China, where citizens gain “social credit” points for purchasing baby goods, or where they lose points for buying cigarettes, or get cut off from the money system altogether for smoking pot or criticizing the Communist Party.

Our transactions say more about us than our words. The more your daily spend is micro-tracked, the more likely you are to face an Orwellian outcome. In this sense, the fight for private payments is a moral one.

Even in democratic societies, there’s a robust debate unfolding as we speak with regard to the potential role of companies like Facebook as creators of corporate currencies. Some fear that Facebook would on-ramp hundreds of millions of people onto its payment platform Libra via existing social media accounts on WhatsApp or Instagram or Messenger, only to harvest the payment activity of users and steer them in certain behavioral directions, or even deplatform users and freeze their money for having certain political opinions.

As initially proposed, Libra’s corporate partners will spend $10 million for the right to own a validator node in the network and help process payments. You might think — wow, that’s a lot of money — for what? Well — beyond earning interest on the hundreds of millions or billions of dollars kept in Libra’s reserve — the “what” could be an unfettered look into a treasure trove of transaction data from wallet activity and in-app purchases.

It’s clear that no matter where we live, to stop Big Brother we must begin to shrink our ever-expanding data profiles.

The less “linked” information about us being disseminated and shared between companies and governments, the harder it is to surveil us, manipulate us, and control us.

Today across most of the world, you can still walk into a store and buy something with cash, giving you financial privacy. But cash is fading in use around the world. It’s estimated that only 8% of daily global transactions are done with paper or metal money, and that number is much lower in places like urban China or Scandinavia. Even in my local neighborhood in California, there are cafes which are going cashless, for safety concerns. By 2030, the number of people who can meaningfully use cash in their daily lives will decrease asymptotically to zero.

My local neighborhood cashless cafe

A cashless society is a surveillance society. Whether it’s with the government-controlled WeChat model or the corporate-controlled Libra model, your day-to-day activities would be tracked. But what if the future could be different? What if we could have the digital equivalent of cash?

There is a possible future where we can transact with each other in increasingly advanced ways that still preserve our privacy — where we innovate rapidly while also preventing mass social engineering and surveillance.

There is, today, a feasible and reasonable road map to a functional reality where you can buy things on Amazon, purchase bus or subway tickets, and subscribe to political magazines or podcasts without disclosing your identity.

What’s interesting is that many people — across partisan lines — want to preserve financial privacy and agree about the threat of the surveillance state. Most just don’t realize that the answer may already be here in the form of Bitcoin and Lightning.

Bitcoin provides the essential monetary substrate for Lightning’s global private payment network.

In this arrangement, Bitcoin operates as the source of value and security for private payments to function. Without Satoshi Nakamoto’s innovation of decentralized payment processing, I wouldn’t have much hope for private payments, as all financial intermediaries are security holes. But lo and behold, Bitcoin is now in its second decade, and you can today send value to anyone else on earth, as long as you both have internet access and a smartphone, without relying on third parties.

The challenge is that for Bitcoin to work, its creators and founding community had to make several trade-offs, choosing to prioritize security and decentralization and censorship-resistance and settlement guarantees over speed and privacy.

But the Lightning Network allows us to take Bitcoin — which is limited on its own to just a handful of global transactions per second and a public, only pseudonymous ledger — and massively upgrade its speed, privacy, and daily transaction volume.

Lightning payments are instant and onion routed, so that they are hard to trace, similar to (if not quite as private as) data flows in the Tor network. If the network keeps growing at its current pace and architecture, it very well may remain decentralized enough to prevent collusion and keep Lightning payments censorship-resistant. Because Lightning isn’t limited to a certain number of transactions per second, it could one day — in combination with ongoing technical upgrades on Bitcoin’s base layer — accommodate the billions of daily transactions necessary for our future planetary needs. And because it’s open source and permissionless, Lightning is available to anyone on earth, regardless of location or age or income or gender or ethnicity, a key factor as we consider a dystopian future where privacy may only be attainable by wealthy and expert individuals.

There are, of course, significant unknowns and potential downsides with Lightning. There is, for example, a scenario (outlined here) where it ends up being too expensive and difficult for users to directly interact with the network (read: run their own node) so they instead begin to rely on third parties for access, seriously compromising privacy and decentralization. At the same time, users may find controlling their own assets daunting or inconvenient, leading to similar compromises. In the early days, merchants may find settling their Lightning balances into fiat money difficult. And there are other private money projects, too, that may win out. Technologists are building Monero, ZCash, Grin, Beam, MobileCoin, and more, in a welcome competition to preserve the values of cash in the digital world. From a human rights activist’s view, the more innovation in the private payments space, the merrier.

Either way, we can’t discount the possibility that Lightning — currently an obscure technology only known to a few — might end up going mainstream, creating the global payment network that we need to preserve privacy and human rights deep into the information age.

Here’s how that might unfold.