The Quantum Issue: Letter From The Editor

Quantum this, quantum that…who put a stupid cat on-chain!?

Ahem. 

Alright, let’s be serious. The threat that a viable, actually functioning, quantum computer would pose to Bitcoin if it were to be built is very serious. It is the concrete example of an existential threat, in every sense of the word. 

One of the bedrock foundations that Bitcoin rests upon is the assumption of a functioning cryptographic system that can be used to produce unforgeable signatures, i.e. that if you follow that system’s protocol properly when signing things, there is no way that anyone but a bitcoin’s rightful owner could produce a signature needed to spend it unless the rightful owner failed to secure their private key from theft. 

Quantum computers toss that right out the window. There goes the integrity of the entire mechanism that is used for owners of bitcoin to authenticate their ownership for the protocol to process their legitimately authorized transactions, and ONLY their legitimately authorized transactions. There’s no way for anyone to actually own anything in the context of the Bitcoin protocol if that assumption breaks. 

Bitcoin breaks if that assumption breaks. 

Thankfully, there are many different cryptographic systems that exist, and not all of them rest on assumptions that a quantum computer breaks. That’s the good news. The bad news is that its all a set of tradeoffs, none of them are ideal, and there are going to be some hard choices that have to be made.