Exactly 10 candies, 10 chewing gums, 1 chocolate bar, and 1 piece of chocolate cake. That was what every child in the world between 3 and 12 years old would receive today: Once a week was "sweets day". It had been like this for centuries already, and it would go on for a few more if everything continued to work according to plan.

Of course that wasn't much if you were a child that studied hard 6 days a week in school and had to do some farm work on top of that, but that was the way of this world. Making sure that about 5000 people all had shelter, food and medical care in a closed system with quite limited resources meant hard work for everybody and required to keep everything in a delicate balance.

As I patiently waited together with my band of close friends for my turn to receive the package with the sweets I tried not to think too much about my approaching 13th birthday and how my weekly ration would drop to half then.

It hadn't always been like that. The records told about the happy first decades after world creation when machines still did most of the farming work, so children didn't have to help there at all, and food was plentiful. But it turned out to be impossible to permanently keep up those levels of consumption and technology, and the equilibrium that we could sustain over centuries was much lower. Still, everybody had enough to eat and could count on medical care if needed.

If everything was almost the same week after week, you started to care about the little differences that occurred. The world had cows of two different breeds, Nicolas and Saberhagen. When the buttercream for the choco cake was made from the milk of the Saberhagen cows, which was the case today, it was a bit more delicious for my taste. That's why last week I had given 5 of my candies to my friend Curt in exchange of his piece of cake today.

"Looking forward to my extra cake" I said to him. When I only got a puzzled look from him I groaned, took out my smartphone and activated it by speaking the wake word "CryptoNote!" I showed him the calendar entry for today displayed on the home screen, reading "Cake from Curt". "Don't tell me you forgot" I warned him. "I sent a copy of that entry to your calendar when you agreed to trade last week because you have a strange tendency to forget such things".

Whenever problems like this one surfaced I thought how much easier things would be if we had some kind of money as a medium of exchange: Curt giving me some "coins" for my 5 candies last week, and with him not being in the mood this week to give up his piece of cake, me just buying an extra one from some other child that needed some money today.

But while RingCT, our world's central AI and de facto government, tolerated some bartering, money was out of question. When challenged it always argued that things were only running so smoothly in this awfully constrained world because resource allocation, down to the level of single pieces of candy, was centralized. RingCT saw no room for people managing resources in addition to that using some kind of official money.

The 2030's and 2040's were rough decades for humanity. More than one time it was on the brink of global war because climate change and population growth gravely impacted the world economy and brought many shifts of power with them.

But in the first years of the 2050's something extraordinary happened: By then the situation had become so bad that people all over the world had really, truly understood that only everybody working together could lead to real improvements, and they became ready to delegate important powers from nation state governments to a true global government: not some mere debating club like the United Nations of earlier days, but something with the authority to overrule anybody and anything at least in environmental matters.

There were other important and remarkable shifts. A long-running trend to steadily erode privacy came to a halt in the 2030's and later even turned itself around. The reason: Bigger and bigger worldwide problems led to a parallel strong rise of extremist groups of all kinds, some of them ready to use outright violence to further their goals. This in turn forced governments to allow citizens some privacy: Without that they simply were too easy a target for those groups.

Take the case of "meat lovers" for illustration. In the middle of the century the world by and large couldn't afford the luxury of mass-producing meat anymore because climate change effects had diminished the total area of arable land by quite some degree, and plant foods became mostly too precious to use for rising animals.

Still there was some meat to be had, for example beef from cows that had grown too old to produce milk in good quantities, and trading such meat was perfectly legal. But if you wanted to buy you had a serious problem on your hand: How to do it without becoming a target of the various fundamentalist groups that in order to "save the planet" tried to totally eliminate meat trade by whatever measure it took?

For many people part of the answer here was a cryptocurrency called Monero that allowed to make fully anonymous payments without the need for any intermediaries like banks or credit card companies. No extremist could scan lists of payments for buys of meat and then harass the buyers if those used Monero.

Of course it also helped that it was a truly global currency, not under the influence of any single country.

And so a cryptocurrency became an important part of world economy that once had been "on the way out" because originally governments and law enforcement organizations had not liked the privacy it provided.

It was still a surprise what role it would play later on in one of humanity's most iconic projects ever.

I decided that the time was ripe to do something about the "currency problem": If RingCT refused to provide us with something, we had to take matters into our hands and create our own currency.

Looking back I wonder how 12-year old me had the guts to go against what basically was the World Government - maybe it was the optimism of the youth!

RingCT hosted a a vast library of software that you were free to try and use as you saw fit as long as it happened in your free time and did not waste any resources as a side-effect. You just had to find the right programs and learn how to operate them yourself. When our world had been born, it still had been quite unclear what software would become useful one day, and so basically everything existing had been collected and stored.

Technically our smartphones could run any of it, either directly on the device or on RingCT's computing cluster, with a smartphone used for display and input.

By looking around in the catalog I had stumbled over a software called Bitcoin that seemed to fit the bill, implementing a virtual currency with a clever system to limit money creation and making a number of cheats, like spending coins twice, almost impossible.

Soon Curt and I ran the first two nodes of a Bitcoin network on our smartphones and exchanged some initially mined coins to test everything. It did not take long until other children joined the network, trading started, and prices for the various sweets in BTC established themselves.

We thought that we were clever and would manage to hide our currency from RingCT. We ran the Bitcoin programs strictly locally on our smartphones, not on the computing cluster, and RingCT was programmed to respect the privacy of those devices unless accessing them was required because of some special circumstances. Furthermore, we instructed everybody to put up some show for RingCT: Whenever an child handed over sweets to another one without immediately receiving some others in exchange, it would babble something along the lines of "Give me yours later", to hide the fact that they would settle the trade using BTC.

We had been too optimistic: After only two weeks our currency stopped to work. RingCT blocked all Bitcoin related data traffic between our smartphones and showed us why there was no point in denying what we had been doing: The Bitcoin blockchain contained all transaction amounts in the clear, and if you knew the prices of the various sweets it was easy to correlate BTC transactions with goods changing hands.

It was quite a surprise to me how the Bitcoin system did not protect information so crucial and sensitive somehow; that seemed to be pretty weak for a virtual currency implementation.

I was convinced that there must be similar software that improved on that, and soon found an alternative in the library: a system called "Monero" with clever privacy mechanisms.

After a waiting time to let things cool down we started to use that as our currency and also made sure that the Monero "daemons" would use private smartphone-to-smartphone connections, so RingCT wouldn't be able to watch transaction transmissions or even put up its own node like it had done with Bitcoin to get a copy of the blockchain to analyze.

That seemed to do the trick, as many weeks went by without RingCT stopping us again.

Now, many years later, new generations of children still use Monero to trade sweets. And since I became a developer it's clear to me that of course RingCT almost immediately knew we had started to use an alternative currency back then. It does not tell why exactly it had not tolerated Bitcoin, but allows children to use Monero to this day. It may sound improbable, but I suspect it has to do with something surprising I had learned in the meantime: the important role the currency had played in bringing our world into being.

It was only natural that many people didn't like Project Ark project: big spaceships with everything on board to keep a population of roughly 5000 people alive for centuries while the ships made their way to their destinations with about one percent of the speed of light. Critics argued vehemently that the resources consumed by building and launching them were much more urgently needed on Earth to help solving the multitude of serious problems.

But a very vocal minority was convinced that assuring humanity's long-term survival was more important than ever, with the possibility for something going fatally and terminally wrong on Earth decidedly being non-zero now.

After much arguing back and forth a consensus was reached: Project Ark would get the green light but wasn't allowed to use any "tax dollars" - funds had to come exclusively from voluntary donations. Nobody should be forced to pay for something so expensive in case they didn't agree with the project.

A cryptocurrency called Monero came to play an important role in financing the arks because it allowed people to donate in an anonymous way and so stay pretty safe from attacks by all the many groups that fought the project. As a "thank you" for this the Monero dev community was invited to name various project-related things, a once-in-a-lifetime chance that people picked up with great enthusiasm.

For most of the names they went back several decades, to the first pioneering years of Monero. And in such a big project there was a large number of very different things to name:

Each ark had a powerful on-board optical telescope, with the important job to gather as much information as possible about the several candidate destination star systems and pick the most promising one about half-way into the journey. People named it Stealth Address Telescope, after one of Monero's primary privacy mechanisms called stealth addresses, making sure that the destinations of transactions were not visible in the blockchain for everyone. The idea was to understand the destination of an ark as the "address" it was heading to, and that being "stealth" for a long time, not yet clearly visible because of the large distances.

The ark's central AI got the name RingCT from another important privacy mechanism, the one that made sure nobody could see the amount of XMR in a Monero transaction except the receiver of the funds. The "backstory" in this case: The arks were long rotating cylinders, so you could say a name with "ring" in it was a good fit, and on top of that claim that "RingCT" was really standing for "ring control" in the case of this AI, making it even better.

Each passenger would have its personal smartphone, and a dedicated new operating system was developed for that. It came with a wake word, in the style of "Siri!", "Alexa!" or "Google!" of early such devices. People chose "CryptoNote!" as that word, the name of the original cryptocurrency technology Monero had been based on, which looked like a good fit because one of the possible uses of the devices would be taking notes.

The ship's propulsion system was christened RandomX, like Monero's proof-of-work consensus mechanism. You could say the "X" hinted at SpaceX, the company who had developed the rocket engines, and that RandomX "powered" Monero's blockchain like those engines would now power the arks.

And then there were the cows. Two new races of cattle were bred that could cope well with the low 0.8 g of "gravity" on the inner surface of the rotating cylinders and the artificial sunlight. Their names Nicolas and Saberhagen were taken from Nicolas van Saberhagen, the pseudonym of the cryptographer that had created the CryptoNote technology when the century had been still quite young, back in 2012.

The proposer of these names had explained that the cryptographer's name sounded Dutch because of the "van", and what were the Netherlands known for? Exactly, cheese made from the milk of many, many cows.

Van Saberhagen was almost certainly not alive anymore, but would surely be quite proud about those breed names if still around!