I have a few questions regarding the longevity of Bitcoin and other cryptocurrencies. My apologies if these seem basic or have been answered elsewhere, as I am still new to the subject.
My first question is what would happen in, say, 40 or 50 years, after the coins have all been mined? Will the network be vulnerable to a 51% attack after there is no more incentive to mine?
This is a valid question. If there is no more incentive to mine, then fewer people will mine, and yes, it could probably be vulnerable to a 51% attack.
But note the
if there. As long as transaction fees per block are enough to incentivize miners to keep the blockchain properly protected, then there's nothing to worry about. Which means that either bitcoins need to become much more valuable than they are now, or the amount of transaction fees per block will eventually need to increase, or both need to occur to some degree. Considering we have well over 100 years before the last 0.00000001 BTC is mined, this should be addressed (or rendered moot) long before then.
Next, what are the expected results of the advent of quantum computing on bitcoins? For instance, I believe that computing hashes should probably become trivial, which means that the distribution of rewarded bitcoins will likely shift to companies and institutions possessing such capabilities, but I'm more concerned and interested in any possible security concerns. For instance, will the hashes for transaction chain blocks be similarly compromised? In a similar note, what about wallets over that time? I expect that most people will be able to keep their clients updated in the circumstance that such a vulnerability becomes critical. But what about a bitcoin wallet that has sat around untouched for fifty years?
Even in the face of quantum computing, bitcoins sitting in a cold storage address that has never been used before (and thus has never had its public key revealed) will still be safe.
A related question is what happens in the case of a wallet that appears suddenly after fifty or a hundred years? And I'm not talking about any discernable effect on the economy. Let's presume that we're talking about a wallet with no more than a few bitcoins that re-enter circulation. Will it still be good, assuming for instance that it was written on, say, an m-disc? Is the network built to handle such ancient currency?
As long as the person knows the private keys (basically just strings of letters and numbers) of the wallet, then even if the keys had to be chiseled into stone, they should still be able to type the keys into their system, import them into a client and spend the money in them.
And finally, what if the decimal point is not sufficient in the long term? For example, say that in the far future, strong AI has become a reality, and it is possible to spin off a trillion sentient beings on a whim, each of whom demand payment in Satoshis? Can the system handle future divisions, if the current eight decimal points prove insufficient? And what would happen to that hypothetical wallet in that case, assuming its owner were incapable of keeping her wallet client updated through such a critical juncture?
The system can be extended to provide more decimal places as needed.
The owner of the ancient wallet would still be able to use their private keys, since extending the precision would not require any change to any keys.
Thus, I am carefully weighing my options. Is Bitcoin stable enough to last the test of time?
Well, most of us here believe and hope that it is. However, we don't know that it is. It's something a gamble (as are most new things)... but it's a risk with an amazing potential payoff.
That's why I'm considering a gift of a couple of bitcoins to each of my daughters for their twenty-first birthdays. Assuming that the promise of the thousand year discs hold true for at least twenty years, I can imagine that it might be a bit more generous gift than the current few hundred dollars it would cost. And also assuming that bitcoins at least hold their value for that long.
I think that's a fine gift. I've done the same for younger relatives, and their "savings accounts" have already grown in value quite a bit. I fully expect them to continue doing so long-term.
But keep in mind, you don't have to just rely on M-discs. Private keys can be stored anywhere that you can store letters and numbers, which means you're not limited to digital media. You could print them onto paper, engrave them in metal, chisel them in stone, or even have them stored on the inside of a solid plastic tschotske you whipped up on a 3D printer. They could be the literal numbers and letters, a QR-Code, or hidden inside of some poem that you wrote that represents the numbers and letters. The possibilities are endless; but of course, you'll want to let them know what the symbols are, and how to access them, and how important it is that they store them safely. It wouldn't be good if the system was so complex that they pull it out after 5 or 10 years, and can't make sense of how to extract the private keys (or worse, can't quite remember what it is.)
