It is likely that the Galaxy Note 2 will be launched in August. As it has taken two weeks to mine my very first bitcoin, it seems unlikely that I will have mined enough to purchase a Note upon release (unless the time between launch and release is about 15 years).

My plan was to bank on the idea that time travel will be possible, and so I would leave a calendar entry for my future self to travel back in time and credit my bitcoin account with the necessary funds that I have mined in the future (my future self can simply snooze the calendar entry for another decade if time travel is not yet possible).

However, it occurs to me that the bitcoin protocol is immune to this type of temporal shenanigans, as any future mined bitcoins are not in the block chain and so cannot be used in contemporary transactions. Even if the source bitcoins were already generated, no transactions would exist that showed them to be mine.

I am impressed that our future selves cannot tamper with bitcoins in the past, but I wanted to confirm that I haven't missed anything. Is there a workaround that my future self could employ so that they didn't have to convert to gold or diamonds first (considering some time travel techniques only permit living tissue and their contents to be transferred).

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    Please note that the Note 2 launch is two weeks away still, and no money has magically appeared in my account as yet. If it hasn't appeared in time, then it means either none of the answers were good enough, or far less likely, I don't discover a way to time travel back to this point to provide the BTC. So keep coming up with the ideas :)
    – Paul
    Commented Aug 2, 2012 at 3:55
  • If time travel was possible, it would be possible to brute force an address. How? Try to crack an address for 10 straight days. Did it work? no, then go back 10 days and start off where you left off. Repeat Commented Mar 8, 2014 at 21:49

8 Answers 8


Your future self could memorize some SatoshiDice secrets after they are revealed. This would allow him to win every dice bet he placed after travelling back in time, since knowledge of a day's secret allows one to determine whether a bet will win or not before placing the bet.

There is a theory that this has already happened.


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    Chris, did that poster exist prior to my question?
    – Paul
    Commented Jul 27, 2012 at 4:28
  • No. I just thought it was a funny idea. Especially how you can quite clearly tell there used to be a 'K' between the 'C' and the arrow thing. Commented Jul 27, 2012 at 17:50
  • Heh, I like it immensely
    – Paul
    Commented Jul 28, 2012 at 2:38
  • Thanks. :) :) :) (one smile was enough - the comment box insisted that my comment wasn't long enough) Commented Jul 28, 2012 at 6:05

Trying to earn money from Bitcoins from the future would not be such a lucrative business as betting on sports events, or playing the lottery. You can't spend coins that haven't been mined yet, and while you could know the exact block chain data that will appear and try selling the miners nonces that will solve their blocks, I don't think it would earn you too much. As a side note, injecting a long part of the blockchain into the Bitcoin network could freak a lot of people out - after all, they would see their money disappearing and appearing from future transactions without them authorising anything.

Knowing information from the future you could try playing on the Bitcoin exchanges, for example by buying a lot of coins soon after Bitcoin was launched for pennies and selling them at the bubble burst for $30 a coin. Moreover, you could start developing GPU or ASIC miners way in advance and be ready to blast everyone out of the water with your futuristic technology. Lastly, you could just create Bitcoin yourself and be Satoshi Nakamoto, the time traveller;).


If it was me, I'd travel back in time to when bitcoins were practically worthless and offer to buy someone a pizza in return for 10,000 BTC. That would make a nice little nest egg for the future...


You could memorize a single private key. In the future (once time travel is invented) you wouldn't mine in the future. Instead you would go back in time, not to the current time but back to 2009. With your future tech mining gear you could trivially mine a significant fraction of the early bitcoins. You may need to consult your time traveler manual to reduce the changes to the timline. For example it likely wouldn't be a good idea to massively inflate the early difficulty and scoop up 99.999% of the coins. You could alert the timeline and prevent Bitcoin from ever taking off. However lets assume that mining a small portion (say 10%) of the first years blocks wouldn't be noticed. You could direct those 262,800 BTC to the private key you memorized in 2013. In the modified timeline you would have to do anything your wallet would "magically" produce a private key which had 262,800 BTC mined to it. Tada, you are instantly wealthy and can buy the Galaxy Note 2.

Of course the fact that your current wallet doesn't contain 262,800 BTC means either time travel hasn't been invented in your lifetime, you for some future reason never make the attempt, or your attempt to travel back in time failed (your future self may have been assassinated by Time Police). On the last possibility it is possible this post gives you the idea which your future self attempts to implement resulting in your death. Of course now that you have the idea it is impossible to un-know it so your future death may be predestined. If that is the case I sincerely apologize for getting you killed in the future.

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    Actually, the safe assumption is that if your approach worked, I would have the BTC right now. As I don't your approach is flawed and so I cannot accept this answer :)
    – Paul
    Commented Jan 22, 2013 at 3:47

If I have a blockchain from the future I could probably go back in time and successfully perform a 51% attack. There wouldn't be any way that I'd benefit financially as I couldn't change that blocks but I could slam a couple hours worth of blocks through.

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    That would be a very strange 51% attack, as it would include transactions that spend coins before people intended to spend them, as if you had the private keys to generate the transactions yourself. All hell would break loose... Commented Aug 2, 2012 at 3:41
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    You can't just copy a naturally-generated future chain because Bitcoin nodes won't accept blocks with a timestamp too far in the future.
    – theymos
    Commented Jan 22, 2013 at 5:03
  1. In the future buy private key(s) that had balances in the past.

  2. In the past listen to a noisy data source tied to hardware random number generator.

  3. In the future use time travel powers to alter the 'noise' your past self listened to by encoding the 'noise' with the private key(s) purchased in step 1.

You could also use your time-travel-information-channel to mine blocks, but this would limit you to 300 BTC/hr.

Happy time traveling. :)

  • 300BTC/hr would net me enough for the phone in 1 hour, so that is fine. But if I now have private keys that have had balance in the past, surely they collide with someone else who already has the keys?
    – Paul
    Commented Jul 28, 2012 at 23:06
  • It is true that if you steal from the private keys that it will be detected. In a sense you are stealing from the miner as well, they just won't notice. Commented Jul 30, 2012 at 16:58

In the future you can also buy some 'vintage' coins that would be in the blockchain in 2013 and send those to your Galaxy Note.


My future self, having invented time-travel would then send a Terminator (in the form of a CAT5/USB-toting R2D2) back in time to the beginning of Bitcoin. Not only would the "R2-Terminator" create a wallet and start mining, but would also follow programmed trading tasks to take advantage of market fluctuations. Unbeknownst to me this is all currently occurring.

Tomorrow at 9.46am GMT my modest Wallet is going to receive the culmination of R2's hard work.

Would you like some for your phone?

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