Digital information can be replicated at zero cost. This is desirable in general, for productivity gains, but not for digital money (money printing, fraud) — money needs to be scarce.

Double-spending is akin to printing money, and strictly speaking, Bitcoin does not solve the DSP, it mitigates it with PoW.

Why can I share my profile pic with millions and still have my own copy, but my #bitcoin with only one person and then not have it anymore?

As soon as I authorize my #btc to by sent to another person’s address, millions of entities across the globe see what I did and save a copy of my action, thus confirming that it’s not in my possession anymore.

If I try to send/spend that same amount later their will be unanimous agreement that I do not have it on my address and therefore can not double spend my previously owned #bitcoin.

To make this possible, all #bitcoin transactions have to be stored in a structured chronological list called a blockchain and the entire blockchain can be saved on any hard drive by anyone.

This fixes the ‘double-spend problem’ 🔐