If quantum computing can reduce previous calculation times of decades down to seconds, then what does that spell for current military, government, and corporate technologies that rely on encryption algorithms? The current idea is that encryption isn’t unbreakable, it’s just not practical because by the time the message is encrypted, it’s no longer relevant and most likely the encryption key (or even mechanism) has changed. With Quantum computing, this all goes out the window, as now brute force decryption could theoretically be done in real time. This terrifies everyone, and rightfully so.
What about Blockchain? Under the bitcoin blockchain algorithm concept, the encryption difficulty is adjusted after every 2016 blocks are mined. This is typically an incremental increase or decrease as more or fewer hardware resources are thrown at mining bitcoin. Thus, if you added a super quantum computer (or cluster of quantum computers), the difficulty would proportionally (and drastically) increase with the number of blocks that were mined (just in a much shorter time frame).
On October 23, 2019, Bitcoin’s price fell from around $8200 per bitcoin to under $7400 in a matter of minutes, because Google announced that Sycamore, its quantum computing platform, had achieved “quantum supremacy” and passed an impossible test. The premise is that it completed a test calculation in 200 seconds that would take the world’s most powerful supercomputer 10,000 years to finish. While the claim is somewhat questionable, there is no doubt that quantum computing has taken a foothold and will only advance from here.
The problem here is that someone trying to break the encryption isn’t likely to be actively participating in the blockchain. They’re just going to be trying to decrypt packets or streams, or whatever they are intercepting and trying to decrypt. So unless the encrypted blockchain communications platform changed the encryption difficulty to a level that it couldn’t actively mine itself (thus defeating the point of encryption to begin with), the communications would always be deciphered by the quantum computer. Thus… all encrypted communications would have to be done with quantum computers. It’s another round of keeping up with the bad guys, and technology has to step up to meet the challenge.
The downside is that this is financially well outside the possibility for most businesses and private individuals, meaning we are back to the equivalent of clear text passwords and messages as well as unencrypted financial transactions. This would be disastrous for the financial and credit industries, as well as creating havoc in terms of privacy act enforcement, worldwide (think GDPR).
How this plays out is anybody’s guess right now and the technology isn’t quite there, but in the mean time, all one can do is hope that Google really means it when they say “Don’t Be Evil”.